Merge branch 'master' into stdenv-updates

Conflicts:
	pkgs/top-level/all-packages.nix

lib/attrsets.nix

@@ -29,9 +29,8 @@ rec {
      ["x" "y"] applied with some value v returns `x.y = v;' */
   setAttrByPath = attrPath: value:
     if attrPath == [] then value
-    else listToAttrs [(
+    else listToAttrs
-      nameValuePair (head attrPath) (setAttrByPath (tail attrPath) value)
+      [ { name = head attrPath; value = setAttrByPath (tail attrPath) value; } ];
-    )];
 
 
   getAttrFromPath = attrPath: set:
@@ -133,7 +132,7 @@ rec {
        => { x = "x-foo"; y = "y-bar"; }
   */
   mapAttrs = f: set:
-    listToAttrs (map (attr: nameValuePair attr (f attr (getAttr attr set))) (attrNames set));
+    listToAttrs (map (attr: { name = attr; value = f attr (getAttr attr set); }) (attrNames set));
 
 
   /* Like `mapAttrs', but allows the name of each attribute to be
@@ -240,7 +239,7 @@ rec {
   # names, hopefully this does not affect the system because the maximal
   # laziness avoid computing twice the same expression and listToAttrs does
   # not care about duplicated attribute names.
-  zipAttrsWith = f: sets: zipWithNames (concatMap attrNames sets) f sets;
+  zipAttrsWith = f: sets: zipAttrsWithNames (concatMap attrNames sets) f sets;
 
   zipAttrs = zipAttrsWith (name: values: values);
 

lib/default.nix

@@ -8,7 +8,6 @@ let
   sources = import ./sources.nix;
   modules = import ./modules.nix;
   options = import ./options.nix;
-  properties = import ./properties.nix;
   types = import ./types.nix;
   meta = import ./meta.nix;
   debug = import ./debug.nix;
@@ -21,13 +20,13 @@ let
 
 in
   { inherit trivial lists strings stringsWithDeps attrsets sources options
-      properties modules types meta debug maintainers licenses platforms systems;
+      modules types meta debug maintainers licenses platforms systems;
     # Pull in some builtins not included elsewhere.
     inherit (builtins) pathExists readFile;
   }
   # !!! don't include everything at top-level; perhaps only the most
   # commonly used functions.
   // trivial // lists // strings // stringsWithDeps // attrsets // sources
-  // properties // options // types // meta // debug // misc // modules
+  // options // types // meta // debug // misc // modules
   // systems
   // customisation

lib/lists.nix

@@ -118,6 +118,11 @@ in rec {
   all = pred: fold (x: y: if pred x then y else false) true;
 
 
+  # Count how many times function `pred' returns true for the elements
+  # of `list'.
+  count = pred: fold (x: c: if pred x then inc c else c) 0;
+
+
   # Return a singleton list or an empty list, depending on a boolean
   # value.  Useful when building lists with optional elements
   # (e.g. `++ optional (system == "i686-linux") flashplayer').
@@ -165,10 +170,11 @@ in rec {
 
   zipLists = zipListsWith (fst: snd: { inherit fst snd; });
 
-  
+
-  # Reverse the order of the elements of a list.
+  # Reverse the order of the elements of a list.  FIXME: O(n^2)!
   reverseList = fold (e: acc: acc ++ [ e ]) [];
 
+
   # Sort a list based on a comparator function which compares two
   # elements and returns true if the first argument is strictly below
   # the second argument.  The returned list is sorted in an increasing

lib/modules.nix

@@ -1,379 +1,312 @@
-# NixOS module handling.
-
-let lib = import ./default.nix; in
-
-with { inherit (builtins) head; };
-with import ./trivial.nix;
 with import ./lists.nix;
-with import ./misc.nix;
+with import ./trivial.nix;
 with import ./attrsets.nix;
 with import ./options.nix;
-with import ./properties.nix;
+with import ./debug.nix;
+with import ./types.nix;
 
 rec {
 
-  # Unfortunately this can also be a string.
+  /* Evaluate a set of modules.  The result is a set of two
-  isPath = x: !(
+     attributes: ‘options’: the nested set of all option declarations,
-     builtins.isFunction x
+     and ‘config’: the nested set of all option values. */
-  || builtins.isAttrs x
+  evalModules = { modules, prefix ? [], args ? {}, check ? true }:
-  || builtins.isInt x
-  || builtins.isBool x
-  || builtins.isList x
-  );
-
-
-  importIfPath = path:
-    if isPath path then
-      import path
-    else
-      path;
-
-
-  applyIfFunction = f: arg:
-    if builtins.isFunction f then
-      f arg
-    else
-      f;
-
-
-  isModule = m:
-       (m ? config && isAttrs m.config && ! isOption m.config)
-    || (m ? options && isAttrs m.options && ! isOption m.options);
-
-
-  # Convert module to a set which has imports / options and config
-  # attributes.
-  unifyModuleSyntax = m:
     let
-      delayedModule = delayProperties m;
+      args' = args // result;
-
+      closed = closeModules modules args';
-      getImports =
+      # Note: the list of modules is reversed to maintain backward
-        toList (rmProperties (delayedModule.require or []));
+      # compatibility with the old module system.  Not sure if this is
-      getImportedPaths = filter isPath getImports;
+      # the most sensible policy.
-      getImportedSets = filter (x: !isPath x) getImports;
+      options = mergeModules prefix (reverseList closed);
-
+      # Traverse options and extract the option values into the final
-      getConfig =
+      # config set.  At the same time, check whether all option
-        removeAttrs delayedModule ["require" "key" "imports"];
+      # definitions have matching declarations.
+      config = yieldConfig prefix options;
+      yieldConfig = prefix: set:
+        let res = removeAttrs (mapAttrs (n: v:
+          if isOption v then v.value
+          else yieldConfig (prefix ++ [n]) v) set) ["_definedNames"];
+        in
+        if check && set ? _definedNames then
+          fold (m: res:
+            fold (name: res:
+              if hasAttr name set then res else throw "The option `${showOption (prefix ++ [name])}' defined in `${m.file}' does not exist.")
+              res m.names)
+            res set._definedNames
+        else
+          res;
+      result = { inherit options config; };
+    in result;
 
+  /* Close a set of modules under the ‘imports’ relation. */
+  closeModules = modules: args:
+    let
+      toClosureList = file: parentKey: imap (n: x:
+        if isAttrs x || builtins.isFunction x then
+          unifyModuleSyntax file "${parentKey}:anon-${toString n}" (applyIfFunction x args)
+        else
+          unifyModuleSyntax (toString x) (toString x) (applyIfFunction (import x) args));
     in
-      if isModule m then
+      builtins.genericClosure {
-        { key = "<unknown location>"; } // m
+        startSet = toClosureList unknownModule "" modules;
+        operator = m: toClosureList m.file m.key m.imports;
+      };
+
+  /* Massage a module into canonical form, that is, a set consisting
+     of ‘options’, ‘config’ and ‘imports’ attributes. */
+  unifyModuleSyntax = file: key: m:
+    if m ? config || m ? options then
+      let badAttrs = removeAttrs m ["imports" "options" "config" "key" "_file"]; in
+      if badAttrs != {} then
+        throw "Module `${key}' has an unsupported attribute `${head (attrNames badAttrs)}'."
       else
-        { key = "<unknown location>";
+        { file = m._file or file;
-          imports = (m.imports or []) ++ getImportedPaths;
+          key = toString m.key or key;
-          config = getConfig;
+          imports = m.imports or [];
-        } // (
+          options = m.options or {};
-          if getImportedSets != [] then
+          config = m.config or {};
-            assert length getImportedSets == 1;
+        }
-            { options = head getImportedSets; }
+    else
+      { file = m._file or file;
+        key = toString m.key or key;
+        imports = m.require or [] ++ m.imports or [];
+        options = {};
+        config = removeAttrs m ["key" "_file" "require" "imports"];
+      };
+
+  applyIfFunction = f: arg: if builtins.isFunction f then f arg else f;
+
+  /* Merge a list of modules.  This will recurse over the option
+     declarations in all modules, combining them into a single set.
+     At the same time, for each option declaration, it will merge the
+     corresponding option definitions in all machines, returning them
+     in the ‘value’ attribute of each option. */
+  mergeModules = prefix: modules:
+    mergeModules' prefix modules
+      (concatMap (m: map (config: { inherit (m) file; inherit config; }) (pushDownProperties m.config)) modules);
+
+  mergeModules' = prefix: options: configs:
+    listToAttrs (map (name: {
+      # We're descending into attribute ‘name’.
+      inherit name;
+      value =
+        let
+          loc = prefix ++ [name];
+          # Get all submodules that declare ‘name’.
+          decls = concatLists (map (m:
+            if hasAttr name m.options
+              then [ { inherit (m) file; options = getAttr name m.options; } ]
+              else []
+            ) options);
+          # Get all submodules that define ‘name’.
+          defns = concatLists (map (m:
+            if hasAttr name m.config
+              then map (config: { inherit (m) file; inherit config; })
+                (pushDownProperties (getAttr name m.config))
+              else []
+            ) configs);
+          nrOptions = count (m: isOption m.options) decls;
+          # Process mkMerge and mkIf properties.
+          defns' = concatMap (m:
+            if hasAttr name m.config
+              then map (m': { inherit (m) file; value = m'; }) (dischargeProperties (getAttr name m.config))
+              else []
+            ) configs;
+        in
+          if nrOptions == length decls then
+            let opt = fixupOptionType loc (mergeOptionDecls loc decls);
+            in evalOptionValue loc opt defns'
+          else if nrOptions != 0 then
+            let
+              firstOption = findFirst (m: isOption m.options) "" decls;
+              firstNonOption = findFirst (m: !isOption m.options) "" decls;
+            in
+              throw "The option `${showOption loc}' in `${firstOption.file}' is a prefix of options in `${firstNonOption.file}'."
           else
-            {}
+            mergeModules' loc decls defns;
-        );
+    }) (concatMap (m: attrNames m.options) options))
+    // { _definedNames = map (m: { inherit (m) file; names = attrNames m.config; }) configs; };
 
+  /* Merge multiple option declarations into a single declaration.  In
+     general, there should be only one declaration of each option.
+     The exception is the ‘options’ attribute, which specifies
+     sub-options.  These can be specified multiple times to allow one
+     module to add sub-options to an option declared somewhere else
+     (e.g. multiple modules define sub-options for ‘fileSystems’). */
+  mergeOptionDecls = loc: opts:
+    fold (opt: res:
+      if opt.options ? default && res ? default ||
+         opt.options ? example && res ? example ||
+         opt.options ? description && res ? description ||
+         opt.options ? apply && res ? apply ||
+         opt.options ? type && res ? type
+      then
+        throw "The option `${showOption loc}' in `${opt.file}' is already declared in ${showFiles res.declarations}."
+      else
+        opt.options // res //
+          { declarations = [opt.file] ++ res.declarations;
+            options = if opt.options ? options then [(toList opt.options.options ++ res.options)] else [];
+          }
+    ) { inherit loc; declarations = []; options = []; } opts;
 
-  unifyOptionModule = {key ? "<unknown location>"}: name: index: m: (args:
+  /* Merge all the definitions of an option to produce the final
+     config value. */
+  evalOptionValue = loc: opt: defs:
     let
-      module = lib.applyIfFunction m args;
+      # Process mkOverride properties, adding in the default
-      key_ = rec {
+      # value specified in the option declaration (if any).
-        file = key;
+      defsFinal = filterOverrides
-        option = name;
+        ((if opt ? default then [{ file = head opt.declarations; value = mkOptionDefault opt.default; }] else []) ++ defs);
-        number = index;
+      files = map (def: def.file) defsFinal;
-        outPath = key;
+      # Type-check the remaining definitions, and merge them if
-      };
+      # possible.
-    in if lib.isModule module then
+      merged =
-      { key = key_; } // module
+        if defsFinal == [] then
-    else
+          throw "The option `${showOption loc}' is used but not defined."
-      { key = key_; options = module; }
+        else
-  );
+          fold (def: res:
-
+            if opt.type.check def.value then res
-
+            else throw "The option value `${showOption loc}' in `${def.file}' is not a ${opt.type.name}.")
-  moduleClosure = initModules: args:
+            (opt.type.merge loc defsFinal) defsFinal;
-    let
+      # Finally, apply the ‘apply’ function to the merged
-      moduleImport = origin: index: m:
+      # value.  This allows options to yield a value computed
-        let m' = applyIfFunction (importIfPath m) args;
+      # from the definitions.
-        in (unifyModuleSyntax m') // {
+      value = (opt.apply or id) merged;
-          # used by generic closure to avoid duplicated imports.
+    in opt //
-          key =
+      { value = addErrorContext "while evaluating the option `${showOption loc}':" value;
-            if isPath m then m
+        definitions = map (def: def.value) defsFinal;
-            else m'.key or (newModuleName origin index);
+        isDefined = defsFinal != [];
-        };
+        inherit files;
-
-      getImports = m: m.imports or [];
-
-      newModuleName = origin: index:
-        "${origin.key}:<import-${toString index}>";
-
-      topLevel = {
-        key = "<top-level>";
       };
 
-    in
+  /* Given a config set, expand mkMerge properties, and push down the
-      (lazyGenericClosure {
+     mkIf properties into the children.  The result is a list of
-        startSet = imap (moduleImport topLevel) initModules;
+     config sets that do not have properties at top-level.  For
-        operator = m: imap (moduleImport m) (getImports m);
+     example,
-      });
 
+       mkMerge [ { boot = set1; } (mkIf cond { boot = set2; services = set3; }) ]
 
-  moduleApply = funs: module:
+     is transformed into
-    lib.mapAttrs (name: value:
+
-      if builtins.hasAttr name funs then
+       [ { boot = set1; } { boot = mkIf cond set2; services mkIf cond set3; } ].
-        let fun = lib.getAttr name funs; in
+
-        fun value
+     This transform is the critical step that allows mkIf conditions
+     to refer to the full configuration without creating an infinite
+     recursion.
+  */
+  pushDownProperties = cfg:
+    if cfg._type or "" == "merge" then
+      concatMap pushDownProperties cfg.contents
+    else if cfg._type or "" == "if" then
+      map (mapAttrs (n: v: mkIf cfg.condition v)) (pushDownProperties cfg.content)
+    else if cfg._type or "" == "override" then
+      map (mapAttrs (n: v: mkOverride cfg.priority v)) (pushDownProperties cfg.content)
+    else
+      [ cfg ];
+
+  /* Given a config value, expand mkMerge properties, and discharge
+     any mkIf conditions.  That is, this is the place where mkIf
+     conditions are actually evaluated.  The result is a list of
+     config values.  For example, ‘mkIf false x’ yields ‘[]’,
+     ‘mkIf true x’ yields ‘[x]’, and
+
+       mkMerge [ 1 (mkIf true 2) (mkIf true (mkIf false 3)) ]
+
+     yields ‘[ 1 2 ]’.
+  */
+  dischargeProperties = def:
+    if def._type or "" == "merge" then
+      concatMap dischargeProperties def.contents
+    else if def._type or "" == "if" then
+      if def.condition then
+        dischargeProperties def.content
       else
-        value
+        [ ]
-    ) module;
-
-
-  # Handle mkMerge function left behind after a delay property.
-  moduleFlattenMerge = module:
-    if module ? config &&
-       isProperty module.config &&
-       isMerge module.config.property
-    then
-      (map (cfg: { key = module.key; config = cfg; }) module.config.content)
-      ++ [ (module // { config = {}; }) ]
     else
-      [ module ];
+      [ def ];
 
+  /* Given a list of config values, process the mkOverride properties,
+     that is, return the values that have the highest (that is,
+     numerically lowest) priority, and strip the mkOverride
+     properties.  For example,
 
-  # Handle mkMerge attributes which are left behind by previous delay
+       [ { file = "/1"; value = mkOverride 10 "a"; }
-  # properties and convert them into a list of modules. Delay properties
+         { file = "/2"; value = mkOverride 20 "b"; }
-  # inside the config attribute of a module and create a second module if a
+         { file = "/3"; value = "z"; }
-  # mkMerge attribute was left behind.
+         { file = "/4"; value = mkOverride 10 "d"; }
-  #
+       ]
-  # Module -> [ Module ]
-  delayModule = module:
-    map (moduleApply { config = delayProperties; }) (moduleFlattenMerge module);
 
+     yields
 
-  evalDefinitions = opt: values:
+       [ { file = "/1"; value = "a"; }
-    if opt.type.delayOnGlobalEval or false then
+         { file = "/4"; value = "d"; }
-      map (delayPropertiesWithIter opt.type.iter opt.name)
+       ]
-        (evalLocalProperties values)
-    else
-      evalProperties values;
 
-
+     Note that "z" has the default priority 100.
-  selectModule = name: m:
+  */
-    { inherit (m) key;
+  filterOverrides = defs:
-    } // (
-      if m ? options && builtins.hasAttr name m.options then
-        { options = lib.getAttr name m.options; }
-      else {}
-    ) // (
-      if m ? config && builtins.hasAttr name m.config then
-        { config = lib.getAttr name m.config; }
-      else {}
-    );
-
-  filterModules = name: modules:
-    filter (m: m ? config || m ? options) (
-      map (selectModule name) modules
-    );
-
-
-  modulesNames = modules:
-    lib.concatMap (m: []
-    ++ optionals (m ? options) (lib.attrNames m.options)
-    ++ optionals (m ? config) (lib.attrNames m.config)
-    ) modules;
-
-
-  moduleZip = funs: modules:
-    lib.mapAttrs (name: fun:
-      fun (catAttrs name modules)
-    ) funs;
-
-
-  moduleMerge = path: modules_:
     let
-      addName = name:
+      defaultPrio = 100;
-        if path == "" then name else path + "." + name;
+      getPrio = def: if def.value._type or "" == "override" then def.value.priority else defaultPrio;
+      min = x: y: if builtins.lessThan x y then x else y;
+      highestPrio = fold (def: prio: min (getPrio def) prio) 9999 defs;
+      strip = def: if def.value._type or "" == "override" then def // { value = def.value.content; } else def;
+    in concatMap (def: if getPrio def == highestPrio then [(strip def)] else []) defs;
 
-      modules = concatLists (map delayModule modules_);
+  /* Hack for backward compatibility: convert options of type
-
+     optionSet to configOf.  FIXME: remove eventually. */
-      modulesOf = name: filterModules name modules;
+  fixupOptionType = loc: opt:
-      declarationsOf = name: filter (m: m ? options) (modulesOf name);
-      definitionsOf  = name: filter (m: m ? config ) (modulesOf name);
-
-      recurseInto = name:
-        moduleMerge (addName name) (modulesOf name);
-
-      recurseForOption = name: modules: args:
-        moduleMerge name (
-          moduleClosure modules args
-        );
-
-      errorSource = modules:
-        "The error may come from the following files:\n" + (
-          lib.concatStringsSep "\n" (
-            map (m:
-              if m ? key then toString m.key else "<unknown location>"
-            ) modules
-          )
-        );
-
-      eol = "\n";
-
-      allNames = modulesNames modules;
-
-      getResults = m:
-        let fetchResult = s: mapAttrs (n: v: v.result) s; in {
-          options = fetchResult m.options;
-          config = fetchResult m.config;
-        };
-
-      endRecursion =  { options = {}; config = {}; };
-
-    in if modules == [] then endRecursion else
-      getResults (fix (crossResults: moduleZip {
-        options = lib.zipWithNames allNames (name: values: rec {
-          config = lib.getAttr name crossResults.config;
-
-          declarations = declarationsOf name;
-          declarationSources =
-            map (m: {
-              source = m.key;
-            }) declarations;
-
-          hasOptions = values != [];
-          isOption = any lib.isOption values;
-
-          decls = # add location to sub-module options.
-            map (m:
-              mapSubOptions
-                (unifyOptionModule {inherit (m) key;} name)
-                m.options
-            ) declarations;
-
-          decl =
-            lib.addErrorContext "${eol
-              }while enhancing option `${addName name}':${eol
-              }${errorSource declarations}${eol
-            }" (
-              addOptionMakeUp
-                { name = addName name; recurseInto = recurseForOption; }
-                (mergeOptionDecls decls)
-            );
-
-          value = decl // (with config; {
-            inherit (config) isNotDefined;
-            isDefined = ! isNotDefined;
-            declarations = declarationSources;
-            definitions = definitionSources;
-            config = strictResult;
-          });
-
-          recurse = (recurseInto name).options;
-
-          result =
-            if isOption then value
-            else if !hasOptions then {}
-            else if all isAttrs values then recurse
-            else
-              throw "${eol
-                }Unexpected type where option declarations are expected.${eol
-                }${errorSource declarations}${eol
-              }";
-
-        });
-
-        config = lib.zipWithNames allNames (name: values_: rec {
-          option = lib.getAttr name crossResults.options;
-
-          definitions = definitionsOf name;
-          definitionSources =
-            map (m: {
-              source = m.key;
-              value = m.config;
-            }) definitions;
-
-          values = values_ ++
-            optionals (option.isOption && option.decl ? extraConfigs)
-              option.decl.extraConfigs;
-
-          defs = evalDefinitions option.decl values;
-
-          isNotDefined = defs == [];
-
-          value =
-            lib.addErrorContext "${eol
-              }while evaluating the option `${addName name}':${eol
-              }${errorSource (modulesOf name)}${eol
-            }" (
-              let opt = option.decl; in
-              opt.apply (
-                if isNotDefined then
-                  opt.default or (throw "Option `${addName name}' not defined and does not have a default value.")
-                else opt.merge defs
-              )
-            );
-
-          strictResult = builtins.tryEval (builtins.toXML value);
-
-          recurse = (recurseInto name).config;
-
-          configIsAnOption = v: isOption (rmProperties v);
-          errConfigIsAnOption =
-            let badModules = filter (m: configIsAnOption m.config) definitions; in
-            "${eol
-              }Option ${addName name} is defined in the configuration section.${eol
-              }${errorSource badModules}${eol
-            }";
-
-          errDefinedWithoutDeclaration =
-            let badModules = definitions; in
-            "${eol
-              }Option '${addName name}' defined without option declaration.${eol
-              }${errorSource badModules}${eol
-            }";
-
-          result =
-            if option.isOption then value
-            else if !option.hasOptions then throw errDefinedWithoutDeclaration
-            else if any configIsAnOption values then throw errConfigIsAnOption
-            else if all isAttrs values then recurse
-            # plain value during the traversal
-            else throw errDefinedWithoutDeclaration;
-
-        });
-      } modules));
-
-
-  fixMergeModules = initModules: {...}@args:
-    lib.fix (result:
-      # This trick avoids an infinite loop because names of attribute
-      # are know and it is not required to evaluate the result of
-      # moduleMerge to know which attributes are present as arguments.
-      let module = { inherit (result) options config; }; in
-      moduleMerge "" (
-        moduleClosure initModules (module // args)
-      )
-    );
-
-
-  # Visit all definitions to raise errors related to undeclared options.
-  checkModule = path: {config, options, ...}@m:
     let
-      eol = "\n";
+      options' = opt.options or
-      addName = name:
+        (throw "Option `${showOption loc'}' has type optionSet but has no option attribute.");
-        if path == "" then name else path + "." + name;
+      coerce = x:
-    in
+        if builtins.isFunction x then x
-    if lib.isOption options then
+        else { config, ... }: { options = x; };
-      if options ? options then
+      options = map coerce (flatten options');
-        options.type.fold
+      f = tp:
-          (cfg: res: res && checkModule (options.type.docPath path) cfg._args)
+        if tp.name == "option set" then types.submodule options
-          true config
+        else if tp.name == "attribute set of option sets" then types.attrsOf (types.submodule options)
-      else
+        else if tp.name == "list or attribute set of option sets" then types.loaOf (types.submodule options)
-        true
+        else if tp.name == "list of option sets" then types.listOf (types.submodule options)
-    else if isAttrs options && lib.attrNames m.options != [] then
+        else if tp.name == "null or option set" then types.nullOr (types.submodule options)
-      all (name:
+        else tp;
-        lib.addErrorContext "${eol
+    in opt // { type = f (opt.type or types.unspecified); };
-          }while checking the attribute `${addName name}':${eol
+
-        }" (checkModule (addName name) (selectModule name m))
+
-      ) (lib.attrNames m.config)
+  /* Properties. */
-    else
+
-      builtins.trace "try to evaluate config ${lib.showVal config}."
+  mkIf = condition: content:
-      false;
+    { _type = "if";
+      inherit condition content;
+    };
+
+  mkAssert = assertion: message: content:
+    mkIf
+      (if assertion then true else throw "\nFailed assertion: ${message}")
+      content;
+
+  mkMerge = contents:
+    { _type = "merge";
+      inherit contents;
+    };
+
+  mkOverride = priority: content:
+    { _type = "override";
+      inherit priority content;
+    };
+
+  mkOptionDefault = mkOverride 1001; # priority of option defaults
+  mkDefault = mkOverride 1000; # used in config sections of non-user modules to set a default
+  mkForce = mkOverride 50;
+  mkVMOverride = mkOverride 10; # used by ‘nixos-rebuild build-vm’
+
+  mkFixStrictness = id; # obsolete, no-op
+
+  # FIXME: Add mkOrder back in. It's not currently used anywhere in
+  # NixOS, but it should be useful.
+
+
+  /* Compatibility. */
+  fixMergeModules = modules: args: evalModules { inherit modules args; check = false; };
 
 }

lib/options.nix

@@ -2,28 +2,27 @@
 
 let lib = import ./default.nix; in
 
-with { inherit (builtins) head length; };
 with import ./trivial.nix;
 with import ./lists.nix;
 with import ./misc.nix;
 with import ./attrsets.nix;
-with import ./properties.nix;
+with import ./strings.nix;
 
 rec {
 
   isOption = lib.isType "option";
-  mkOption = attrs: attrs // {
+  mkOption =
-    _type = "option";
+    { default ? null # Default value used when no definition is given in the configuration.
-    # name (this is the name of the attributem it is automatically generated by the traversal)
+    , defaultText ? null # Textual representation of the default, for in the manual.
-    # default (value used when no definition exists)
+    , example ? null # Example value used in the manual.
-    # example (documentation)
+    , description ? null # String describing the option.
-    # description (documentation)
+    , type ? null # Option type, providing type-checking and value merging.
-    # type (option type, provide a default merge function and ensure type correctness)
+    , apply ? null # Function that converts the option value to something else.
-    # merge (function used to merge definitions into one definition: [ /type/ ] -> /type/)
+    , internal ? null # Whether the option is for NixOS developers only.
-    # apply (convert the option value to ease the manipulation of the option result)
+    , visible ? null # Whether the option shows up in the manual.
-    # options (set of sub-options declarations & definitions)
+    , options ? null # Obsolete, used by types.optionSet.
-    # extraConfigs (list of possible configurations)
+    } @ attrs:
-  };
+    attrs // { _type = "option"; };
 
   mkEnableOption = name: mkOption {
     default = false;
@@ -32,261 +31,65 @@ rec {
     type = lib.types.bool;
   };
 
-  mapSubOptions = f: opt:
+  mergeDefaultOption = loc: defs:
-    if opt ? options then
+    let list = getValues defs; in
-      opt // {
-        options = imap f (toList opt.options);
-      }
-    else
-      opt;
-
-  # Make the option declaration more user-friendly by adding default
-  # settings and some verifications based on the declaration content (like
-  # type correctness).
-  addOptionMakeUp = {name, recurseInto}: decl:
-    let
-      init = {
-        inherit name;
-        merge = mergeDefaultOption;
-        apply = lib.id;
-      };
-
-      functionsFromType = opt:
-        opt // (builtins.intersectAttrs { merge = 1; check = 1; } (decl.type or {})); 
-
-      addDeclaration = opt: opt // decl;
-
-      ensureMergeInputType = opt:
-        if opt ? check then
-          opt // {
-            merge = list:
-              if all opt.check list then
-                opt.merge list
-              else
-                throw "A value of the option `${name}' has a bad type.";
-          }
-        else opt;
-
-      checkDefault = opt:
-        if opt ? check && opt ? default then
-          opt // {
-            default =
-              if opt.check opt.default then
-                opt.default
-              else
-                throw "The default value of the option `${name}' has a bad type.";
-          }
-        else opt;
-
-      handleOptionSets = opt:
-        if opt ? type && opt.type.hasOptions then
-          let
-            # Evaluate sub-modules.
-            subModuleMerge = path: vals:
-              lib.fix (args:
-                let
-                  result = recurseInto path (opt.options ++ imap (index: v: args: {
-                    key = rec {
-                      #!!! Would be nice if we had the file the val was from
-                      option = path;
-                      number = index;
-                      outPath = "option ${option} config number ${toString number}";
-                    };
-                  } // (lib.applyIfFunction v args)) (toList vals)) args;
-                  name = lib.removePrefix (opt.name + ".") path;
-                  extraArgs = opt.extraArgs or {};
-                  individualExtraArgs = opt.individualExtraArgs or {};
-                in {
-                  inherit (result) config options;
-                  inherit name;
-                } //
-                  (opt.extraArgs or {}) //
-                  (if hasAttr name individualExtraArgs then getAttr name individualExtraArgs else {})
-              );
-
-            # Add _options in sub-modules to make it viewable from other
-            # modules.
-            subModuleMergeConfig = path: vals:
-              let result = subModuleMerge path vals; in
-                { _args = result; } // result.config;
-
-          in
-            opt // {
-              merge = list:
-                opt.type.iter
-                  subModuleMergeConfig
-                  opt.name
-                  (opt.merge list);
-              options =
-                let path = opt.type.docPath opt.name; in
-                  (subModuleMerge path []).options;
-            }
-        else
-          opt;
-    in
-      foldl (opt: f: f opt) init [
-        # default settings
-        functionsFromType
-
-        # user settings
-        addDeclaration
-
-        # override settings
-        ensureMergeInputType
-        checkDefault
-        handleOptionSets
-      ];
-
-  # Merge a list of options containning different field.  This is useful to
-  # separate the merge & apply fields from the interface.
-  mergeOptionDecls = opts:
-    if opts == [] then {}
-    else if length opts == 1 then
-      let opt = head opts; in
-      if opt ? options then
-        opt // { options = toList opt.options; }
-      else
-        opt
-    else
-      fold (opt1: opt2:
-        lib.addErrorContext "opt1 = ${lib.showVal opt1}\nopt2 = ${lib.showVal opt2}" (
-        # You cannot merge if two options have the same field.
-        assert opt1 ? default -> ! opt2 ? default;
-        assert opt1 ? example -> ! opt2 ? example;
-        assert opt1 ? description -> ! opt2 ? description;
-        assert opt1 ? merge -> ! opt2 ? merge;
-        assert opt1 ? apply -> ! opt2 ? apply;
-        assert opt1 ? type -> ! opt2 ? type;
-        opt1 // opt2
-        // optionalAttrs (opt1 ? options || opt2 ? options) {
-            options =
-               (toList (opt1.options or []))
-            ++ (toList (opt2.options or []));
-          }
-        // optionalAttrs (opt1 ? extraConfigs || opt2 ? extraConfigs) {
-            extraConfigs = opt1.extraConfigs or [] ++ opt2.extraConfigs or [];
-          }
-        // optionalAttrs (opt1 ? extraArgs || opt2 ? extraArgs) {
-            extraArgs = opt1.extraArgs or {} // opt2.extraArgs or {};
-          }
-        // optionalAttrs (opt1 ? individualExtraArgs || opt2 ? individualExtraArgs) {
-            individualExtraArgs = zipAttrsWith (name: values:
-              if length values == 1 then head values else (head values // (head (tail values)))
-            ) [ (opt1.individualExtraArgs or {}) (opt2.individualExtraArgs or {}) ];
-          }
-      )) {} opts;
-
-  
-  # !!! This function will be removed because this can be done with the
-  # multiple option declarations.
-  addDefaultOptionValues = defs: opts: opts //
-    builtins.listToAttrs (map (defName:
-      { name = defName;
-        value = 
-          let
-            defValue = builtins.getAttr defName defs;
-            optValue = builtins.getAttr defName opts;
-          in
-          if isOption defValue
-          then
-            # `defValue' is an option.
-            if hasAttr defName opts
-            then builtins.getAttr defName opts
-            else defValue.default
-          else
-            # `defValue' is an attribute set containing options.
-            # So recurse.
-            if hasAttr defName opts && isAttrs optValue 
-            then addDefaultOptionValues defValue optValue
-            else addDefaultOptionValues defValue {};
-      }
-    ) (attrNames defs));
-
-  mergeDefaultOption = list:
     if length list == 1 then head list
-    else if all builtins.isFunction list then x: mergeDefaultOption (map (f: f x) list)
+    else if all builtins.isFunction list then x: mergeDefaultOption loc (map (f: f x) list)
     else if all isList list then concatLists list
     else if all isAttrs list then fold lib.mergeAttrs {} list
     else if all builtins.isBool list then fold lib.or false list
     else if all builtins.isString list then lib.concatStrings list
-    else if all builtins.isInt list && all (x: x == head list) list
+    else if all builtins.isInt list && all (x: x == head list) list then head list
-         then head list
+    else throw "Cannot merge definitions of `${showOption loc}' given in ${showFiles (getFiles defs)}.";
-    else throw "Cannot merge values.";
 
-  mergeTypedOption = typeName: predicate: merge: list:
+  /* Obsolete, will remove soon.  Specify an option type or apply
-    if all predicate list then merge list
+     function instead.  */
-    else throw "Expect a ${typeName}.";
+  mergeTypedOption = typeName: predicate: merge: loc: list:
+    let list' = map (x: x.value) list; in
+    if all predicate list then merge list'
+    else throw "Expected a ${typeName}.";
 
   mergeEnableOption = mergeTypedOption "boolean"
     (x: true == x || false == x) (fold lib.or false);
 
   mergeListOption = mergeTypedOption "list" isList concatLists;
 
-  mergeStringOption = mergeTypedOption "string"
+  mergeStringOption = mergeTypedOption "string" builtins.isString lib.concatStrings;
-    (x: if builtins ? isString then builtins.isString x else x + "")
-    lib.concatStrings;
 
-  mergeOneOption = list:
+  mergeOneOption = loc: defs:
-    if list == [] then abort "This case should never happen."
+    if defs == [] then abort "This case should never happen."
-    else if length list != 1 then throw "Multiple definitions. Only one is allowed for this option."
+    else if length defs != 1 then
-    else head list;
+      throw "The unique option `${showOption loc}' is defined multiple times, in ${showFiles (getFiles defs)}."
+    else (head defs).value;
 
-
+  getValues = map (x: x.value);
-  fixableMergeFun = merge: f: config:
+  getFiles = map (x: x.file);
-    merge (
-      # generate the list of option sets.
-      f config
-    );
-
-  fixableMergeModules = merge: initModules: {...}@args: config:
-    fixableMergeFun merge (config:
-      lib.moduleClosure initModules (args // { inherit config; })
-    ) config;
-
-
-  fixableDefinitionsOf = initModules: {...}@args:
-    fixableMergeModules (modules: (lib.moduleMerge "" modules).config) initModules args;
-
-  fixableDeclarationsOf = initModules: {...}@args:
-    fixableMergeModules (modules: (lib.moduleMerge "" modules).options) initModules args;
-
-  definitionsOf = initModules: {...}@args:
-    (lib.fix (module:
-      fixableMergeModules (lib.moduleMerge "") initModules args module.config
-    )).config;
-
-  declarationsOf = initModules: {...}@args:
-    (lib.fix (module:
-      fixableMergeModules (lib.moduleMerge "") initModules args module.config
-    )).options;
 
 
   # Generate documentation template from the list of option declaration like
   # the set generated with filterOptionSets.
-  optionAttrSetToDocList = attrs:
+  optionAttrSetToDocList = optionAttrSetToDocList' [];
-    let options = collect isOption attrs; in
-      fold (opt: rest:
-        let
-          docOption = {
-            inherit (opt) name;
-            description = opt.description or (throw "Option ${opt.name}: No description.");
-            declarations = map (x: toString x.source) opt.declarations;
-            #definitions = map (x: toString x.source) opt.definitions;
-            internal = opt.internal or false;
-            visible = opt.visible or true;
-          }
-          // optionalAttrs (opt ? example) { example = scrubOptionValue opt.example; }
-          // optionalAttrs (opt ? default) { default = scrubOptionValue opt.default; }
-          // optionalAttrs (opt ? defaultText) { default = opt.defaultText; };
 
-          subOptions =
+  optionAttrSetToDocList' = prefix: options:
-            if opt ? options then
+    fold (opt: rest:
-              optionAttrSetToDocList opt.options
+      let
-            else
+        docOption = rec {
-              [];
+          name = showOption opt.loc;
-        in
+          description = opt.description or (throw "Option `${name}' has no description.");
-          [ docOption ] ++ subOptions ++ rest
+          declarations = filter (x: x != unknownModule) opt.declarations;
-      ) [] options;
+          internal = opt.internal or false;
+          visible = opt.visible or true;
+        }
+        // optionalAttrs (opt ? example) { example = scrubOptionValue opt.example; }
+        // optionalAttrs (opt ? default) { default = scrubOptionValue opt.default; }
+        // optionalAttrs (opt ? defaultText) { default = opt.defaultText; };
+
+        subOptions =
+          let ss = opt.type.getSubOptions opt.loc;
+          in if ss != {} then optionAttrSetToDocList' opt.loc ss else [];
+      in
+        # FIXME: expensive, O(n^2)
+        [ docOption ] ++ subOptions ++ rest) [] (collect isOption options);
 
 
   /* This function recursively removes all derivation attributes from
@@ -295,7 +98,8 @@ rec {
      representation of derivations is very large (on the order of
      megabytes) and is not actually used by the manual generator. */
   scrubOptionValue = x:
-    if isDerivation x then { type = "derivation"; drvPath = x.name; outPath = x.name; name = x.name; }
+    if isDerivation x then
+      { type = "derivation"; drvPath = x.name; outPath = x.name; name = x.name; }
     else if isList x then map scrubOptionValue x
     else if isAttrs x then mapAttrs (n: v: scrubOptionValue v) (removeAttrs x ["_args"])
     else x;
@@ -308,4 +112,9 @@ rec {
   literalExample = text: { _type = "literalExample"; inherit text; };
 
 
+  /* Helper functions. */
+  showOption = concatStringsSep ".";
+  showFiles = files: concatStringsSep " and " (map (f: "`${f}'") files);
+  unknownModule = "<unknown-file>";
+
 }

lib/properties.nix

@@ -1,464 +0,0 @@
-# Nixpkgs/NixOS properties.  Generalize the problem of delayable (not yet
-# evaluable) properties like mkIf.
-
-let lib = import ./default.nix; in
-
-with { inherit (builtins) head tail; };
-with import ./trivial.nix;
-with import ./lists.nix;
-with import ./misc.nix;
-with import ./attrsets.nix;
-
-rec {
-
-  inherit (lib) isType;
-
-  # Tell that nothing is defined.  When properties are evaluated, this type
-  # is used to remove an entry.  Thus if your property evaluation semantic
-  # implies that you have to mute the content of an attribute, then your
-  # property should produce this value.
-  isNotdef = isType "notdef";
-  mkNotdef = {_type = "notdef";};
-
-  # General property type, it has a property attribute and a content
-  # attribute.  The property attribute refers to an attribute set which
-  # contains a _type attribute and a list of functions which are used to
-  # evaluate this property.  The content attribute is used to stack properties
-  # on top of each other.
-  #
-  # The optional functions which may be contained in the property attribute
-  # are:
-  #  - onDelay: run on a copied property.
-  #  - onGlobalDelay: run on all copied properties.
-  #  - onEval: run on an evaluated property.
-  #  - onGlobalEval: run on a list of property stack on top of their values.
-  isProperty = isType "property";
-  mkProperty = p@{property, content, ...}: p // {
-    _type = "property";
-  };
-
-  # Go through the stack of properties and apply the function `op' on all
-  # property and call the function `nul' on the final value which is not a
-  # property.  The stack is traversed in reversed order.  The `op' function
-  # should expect a property with a content which have been modified.
-  #
-  # Warning: The `op' function expects only one argument in order to avoid
-  # calls to mkProperties as the argument is already a valid property which
-  # contains the result of the folding inside the content attribute.
-  foldProperty = op: nul: attrs:
-    if isProperty attrs then
-      op (attrs // {
-        content = foldProperty op nul attrs.content;
-      })
-    else
-      nul attrs;
-
-  # Simple function which can be used as the `op' argument of the
-  # foldProperty function.  Properties that you don't want to handle can be
-  # ignored with the `id' function.  `isSearched' is a function which should
-  # check the type of a property and return a boolean value.  `thenFun' and
-  # `elseFun' are functions which behave as the `op' argument of the
-  # foldProperty function.
-  foldFilter = isSearched: thenFun: elseFun: attrs:
-    if isSearched attrs.property then
-      thenFun attrs
-    else
-      elseFun attrs;
-
-
-  # Move properties from the current attribute set to the attribute
-  # contained in this attribute set.  This trigger property handlers called
-  # `onDelay' and `onGlobalDelay'.
-  delayPropertiesWithIter = iter: path: attrs:
-    let cleanAttrs = rmProperties attrs; in
-    if isProperty attrs then
-      iter (a: v:
-        lib.addErrorContext "while moving properties on the attribute `${a}':" (
-          triggerPropertiesGlobalDelay a (
-            triggerPropertiesDelay a (
-              copyProperties attrs v
-      )))) path cleanAttrs
-    else
-      attrs;
-
-  delayProperties = # implicit attrs argument.
-    let
-      # mapAttrs except that it also recurse into potential mkMerge
-      # functions.  This may cause a strictness issue because looking the
-      # type of a string implies evaluating it.
-      iter = fun: path: value:
-        lib.mapAttrs (attr: val:
-          if isProperty val && isMerge val.property then
-            val // { content = map (fun attr) val.content; }
-          else
-            fun attr val
-        ) value;
-    in
-      delayPropertiesWithIter iter "";
-
-  # Call onDelay functions.
-  triggerPropertiesDelay = name: attrs:
-    let
-      callOnDelay = p@{property, ...}:
-        if property ? onDelay then
-          property.onDelay name p
-        else
-          p;
-    in
-      foldProperty callOnDelay id attrs;
-
-  # Call onGlobalDelay functions.
-  triggerPropertiesGlobalDelay = name: attrs:
-    let
-      globalDelayFuns = uniqListExt {
-        getter = property: property._type;
-        inputList = foldProperty (p@{property, content, ...}:
-          if property ? onGlobalDelay then
-            [ property ] ++ content
-          else
-            content
-        ) (a: []) attrs;
-      };
-
-      callOnGlobalDelay = property: content:
-        property.onGlobalDelay name content;
-    in
-      fold callOnGlobalDelay attrs globalDelayFuns;
-
-  # Expect a list of values which may have properties and return the same
-  # list of values where all properties have been evaluated and where all
-  # ignored values are removed.  This trigger property handlers called
-  # `onEval' and `onGlobalEval'.
-  evalProperties = valList:
-    if valList != [] then
-      filter (x: !isNotdef x) (
-        triggerPropertiesGlobalEval (
-          evalLocalProperties valList
-        )
-      )
-    else
-      valList;
-
-  evalLocalProperties = valList:
-    filter (x: !isNotdef x) (
-      map triggerPropertiesEval valList
-    );
-
-  # Call onEval function
-  triggerPropertiesEval = val:
-    foldProperty (p@{property, ...}:
-      if property ? onEval then
-        property.onEval p
-      else
-        p
-    ) id val;
-
-  # Call onGlobalEval function
-  triggerPropertiesGlobalEval = valList:
-    let
-      globalEvalFuns = uniqListExt {
-        getter = property: property._type;
-        inputList =
-          fold (attrs: list:
-            foldProperty (p@{property, content, ...}:
-              if property ? onGlobalEval then
-                [ property ] ++ content
-              else
-                content
-            ) (a: list) attrs
-          ) [] valList;
-      };
-
-      callOnGlobalEval = property: valList: property.onGlobalEval valList;
-    in
-      fold callOnGlobalEval valList globalEvalFuns;
-
-  # Remove all properties on top of a value and return the value.
-  rmProperties =
-    foldProperty (p@{content, ...}: content) id;
-
-  # Copy properties defined on a value on another value.
-  copyProperties = attrs: newAttrs:
-    foldProperty id (x: newAttrs) attrs;
-
-  /* Merge. */
-
-  # Create "merge" statement which is skipped by the delayProperty function
-  # and interpreted by the underlying system using properties (modules).
-
-  # Create a "Merge" property which only contains a condition.
-  isMerge = isType "merge";
-  mkMerge = content: mkProperty {
-    property = {
-      _type = "merge";
-      onDelay = name: val: throw "mkMerge is not the first of the list of properties.";
-      onEval = val: throw "mkMerge is not allowed on option definitions.";
-    };
-    inherit content;
-  };
-
-  /* If. ThenElse. Always. */
-
-  # create "if" statement that can be delayed on sets until a "then-else" or
-  # "always" set is reached.  When an always set is reached the condition
-  # is ignore.
-
-  # Create a "If" property which only contains a condition.
-  isIf = isType "if";
-  mkIf = condition: content: mkProperty {
-    property = {
-      _type = "if";
-      onGlobalDelay = onIfGlobalDelay;
-      onEval = onIfEval;
-      inherit condition;
-    };
-    inherit content;
-  };
-
-  mkAssert = assertion: message: content:
-    mkIf
-      (if assertion then true else throw "\nFailed assertion: ${message}")
-      content;
-
-  # Evaluate the "If" statements when either "ThenElse" or "Always"
-  # statement is encountered.  Otherwise it removes multiple If statements and
-  # replaces them by one "If" statement where the condition is the list of all
-  # conditions joined with a "and" operation.
-  onIfGlobalDelay = name: content:
-    let
-      # extract if statements and non-if statements and repectively put them
-      # in the attribute list and attrs.
-      ifProps =
-        foldProperty
-          (foldFilter (p: isIf p)
-            # then, push the condition inside the list list
-            (p@{property, content, ...}:
-              { inherit (content) attrs;
-                list = [property] ++ content.list;
-              }
-            )
-            # otherwise, add the propertie.
-            (p@{property, content, ...}:
-              { inherit (content) list;
-                attrs = p // { content = content.attrs; };
-              }
-            )
-          )
-          (attrs: { list = []; inherit attrs; })
-          content;
-
-      # compute the list of if statements.
-      evalIf = content: condition: list:
-        if list == [] then
-          mkIf condition content
-        else
-          let p = head list; in
-          evalIf content (condition && p.condition) (tail list);
-    in
-      evalIf ifProps.attrs true ifProps.list;
-
-  # Evaluate the condition of the "If" statement to either get the value or
-  # to ignore the value.
-  onIfEval = p@{property, content, ...}:
-    if property.condition then
-      content
-    else
-      mkNotdef;
-
-  /* mkOverride */
-
-  # Create an "Override" statement which allow the user to define
-  # priorities between values.  The default priority is 100. The lowest
-  # priorities are kept.  The template argument must reproduce the same
-  # attribute set hierarchy to override leaves of the hierarchy.
-  isOverride = isType "override";
-  mkOverrideTemplate = priority: template: content: mkProperty {
-    property = {
-      _type = "override";
-      onDelay = onOverrideDelay;
-      onGlobalEval = onOverrideGlobalEval;
-      inherit priority template;
-    };
-    inherit content;
-  };
-
-  # Like mkOverrideTemplate, but without the template argument.
-  mkOverride = priority: content: mkOverrideTemplate priority {} content;
-
-  # Sugar to override the default value of the option by making a new
-  # default value based on the configuration.
-  mkDefaultValue = mkOverride 1000;
-  mkDefault = mkOverride 1000;
-  mkForce = mkOverride 50;
-  mkStrict = mkOverride 0;
-
-  # Make the template traversal in function of the property traversal.  If
-  # the template define a non-empty attribute set, then the property is
-  # copied only on all mentionned attributes inside the template.
-  # Otherwise, the property is kept on all sub-attribute definitions.
-  onOverrideDelay = name: p@{property, content, ...}:
-    let inherit (property) template; in
-    if isAttrs template && template != {} then
-      if hasAttr name template then
-        p // {
-          property = p.property // {
-            template = builtins.getAttr name template;
-          };
-        }
-      # Do not override the attribute \name\
-      else
-        content
-    # Override values defined inside the attribute \name\.
-    else
-      p;
-
-  # Keep values having lowest priority numbers only throwing away those having
-  # a higher priority assigned.
-  onOverrideGlobalEval = valList:
-    let
-      defaultPrio = 100;
-
-      inherit (builtins) lessThan;
-
-      getPrioVal =
-        foldProperty
-          (foldFilter isOverride
-            (p@{property, content, ...}:
-              if content ? priority && lessThan content.priority property.priority then
-                content
-              else
-                content // {
-                  inherit (property) priority;
-                }
-            )
-            (p@{property, content, ...}:
-              content // {
-                value = p // { content = content.value; };
-              }
-            )
-          ) (value: { inherit value; });
-
-      addDefaultPrio = x:
-        if x ? priority then x
-        else x // { priority = defaultPrio; };
-
-      prioValList = map (x: addDefaultPrio (getPrioVal x)) valList;
-
-      higherPrio =
-        if prioValList == [] then
-          defaultPrio
-        else
-          fold (x: min:
-            if lessThan x.priority min then
-              x.priority
-            else
-              min
-          ) (head prioValList).priority (tail prioValList);
-    in
-      map (x:
-        if x.priority == higherPrio then
-          x.value
-        else
-          mkNotdef
-      ) prioValList;
-
-  /* mkOrder */
-
-  # Order definitions based on there index value.  This property is useful
-  # when the result of the merge function depends on the order on the
-  # initial list.  (e.g. concatStrings) Definitions are ordered based on
-  # their rank.  The lowest ranked definition would be the first to element
-  # of the list used by the merge function.  And the highest ranked
-  # definition would be the last.  Definitions which does not have any rank
-  # value have the default rank of 100.
-  isOrder = isType "order";
-  mkOrder = rank: content: mkProperty {
-    property = {
-      _type = "order";
-      onGlobalEval = onOrderGlobalEval;
-      inherit rank;
-    };
-    inherit content;
-  };
-
-  mkHeader = mkOrder 10;
-  mkFooter = mkOrder 1000;
-
-  # Fetch the rank of each definition (add the default rank is none) and
-  # sort them based on their ranking.
-  onOrderGlobalEval = valList:
-    let
-      defaultRank = 100;
-
-      inherit (builtins) lessThan;
-
-      getRankVal =
-        foldProperty
-          (foldFilter isOrder
-            (p@{property, content, ...}:
-              if content ? rank then
-                content
-              else
-                content // {
-                  inherit (property) rank;
-                }
-            )
-            (p@{property, content, ...}:
-              content // {
-                value = p // { content = content.value; };
-              }
-            )
-          ) (value: { inherit value; });
-
-      addDefaultRank = x:
-        if x ? rank then x
-        else x // { rank = defaultRank; };
-
-      rankValList = map (x: addDefaultRank (getRankVal x)) valList;
-
-      cmp = x: y:
-        builtins.lessThan x.rank y.rank;
-    in
-      map (x: x.value) (sort cmp rankValList);
-
-  /* mkFixStrictness */
-
-  # This is a hack used to restore laziness on some option definitions.
-  # Some option definitions are evaluated when they are not used.  This
-  # error is caused by the strictness of type checking builtins.  Builtins
-  # like 'isAttrs' are too strict because they have to evaluate their
-  # arguments to check if the type is correct.  This evaluation, cause the
-  # strictness of properties.
-  #
-  # Properties can be stacked on top of each other.  The stackability of
-  # properties on top of the option definition is nice for user manipulation
-  # but require to check if the content of the property is not another
-  # property.  Such testing implies to verify if this is an attribute set
-  # and if it possess the type 'property'. (see isProperty & typeOf/isType)
-  #
-  # To avoid strict evaluation of option definitions, 'mkFixStrictness' is
-  # introduced.  This property protects an option definition by replacing
-  # the base of the stack of properties by 'mkNotDef', when this property is
-  # evaluated it returns the original definition.
-  #
-  # This property is useful over any elements which depends on options which
-  # are raising errors when they get evaluated without the proper settings.
-  #
-  # Plain list and attribute set are lazy structures, which means that the
-  # container gets evaluated but not the content.  Thus, using this property
-  # on top of plain list or attribute set is pointless.
-  #
-  # This is a Hack, you should avoid it!
-
-  # This property has a long name because you should avoid it.
-  isFixStrictness = attrs: (typeOf attrs) == "fix-strictness";
-  mkFixStrictness = value:
-    mkProperty {
-      property = {
-        _type = "fix-strictness";
-        onEval = p: value;
-      };
-      content = mkNotdef;
-    };
-
-}

lib/systems.nix

@@ -22,7 +22,7 @@ rec {
   };
 
 
-  isCpuType = x: typeOf x == "cpu-type"
+  isCpuType = x: isType "cpu-type" x
     && elem x.bits [8 16 32 64 128]
     && (builtins.lessThan 8 x.bits -> isSignificantByte x.significantByte);
 
@@ -69,7 +69,7 @@ rec {
   };
 
 
-  isSystem = x: typeOf x == "system"
+  isSystem = x: isType "system" x
     && isCpuType x.cpu
     && isArchitecture x.arch
     && isKernel x.kernel;

lib/types.nix

@@ -1,17 +1,15 @@
 # Definitions related to run-time type checking.  Used in particular
 # to type-check NixOS configurations.
 
-let lib = import ./default.nix; in
-
 with import ./lists.nix;
 with import ./attrsets.nix;
 with import ./options.nix;
 with import ./trivial.nix;
+with import ./strings.nix;
 
 rec {
 
   isType = type: x: (x._type or "") == type;
-  hasType = x: isAttrs x && x ? _type;
   typeOf = x: x._type or "";
 
   setType = typeName: value: value // {
@@ -19,208 +17,194 @@ rec {
   };
 
 
-  # name (name of the type)
-  # check (check the config value. Before returning false it should trace the bad value eg using traceValIfNot)
-  # merge (default merge function)
-  # iter (iterate on all elements contained in this type)
-  # fold (fold all elements contained in this type)
-  # hasOptions (boolean: whatever this option contains an option set)
-  # delayOnGlobalEval (boolean: should properties go through the evaluation of this option)
-  # docPath (path concatenated to the option name contained in the option set)
   isOptionType = isType "option-type";
   mkOptionType =
-    { name
+    { # Human-readable representation of the type.
-    , check ? (x: true)
+      name
-    , merge ? mergeDefaultOption
+    , # Function applied to each definition that should return true if
-    # Handle complex structure types.
+      # its type-correct, false otherwise.
-    , iter ? (f: path: v: f path v)
+      check ? (x: true)
-    , fold ? (op: nul: v: op v nul)
+    , # Merge a list of definitions together into a single value.
-    , docPath ? lib.id
+      # This function is called with two arguments: the location of
-    # If the type can contains option sets.
+      # the option in the configuration as a list of strings
-    , hasOptions ? false
+      # (e.g. ["boot" "loader "grub" "enable"]), and a list of
-    , delayOnGlobalEval ? false
+      # definition values and locations (e.g. [ { file = "/foo.nix";
+      # value = 1; } { file = "/bar.nix"; value = 2 } ]).
+      merge ? mergeDefaultOption
+    , # Return a flat list of sub-options.  Used to generate
+      # documentation.
+      getSubOptions ? prefix: {}
     }:
-
     { _type = "option-type";
-      inherit name check merge iter fold docPath hasOptions delayOnGlobalEval;
+      inherit name check merge getSubOptions;
     };
 
 
   types = rec {
 
+    unspecified = mkOptionType {
+      name = "unspecified";
+    };
+
     bool = mkOptionType {
       name = "boolean";
-      check = lib.traceValIfNot builtins.isBool;
+      check = builtins.isBool;
-      merge = fold lib.or false;
+      merge = loc: fold (x: y: x.value || y) false;
     };
 
     int = mkOptionType {
       name = "integer";
-      check = lib.traceValIfNot builtins.isInt;
+      check = builtins.isInt;
+      merge = mergeOneOption;
     };
 
-    string = mkOptionType {
+    str = mkOptionType {
       name = "string";
-      check = lib.traceValIfNot builtins.isString;
+      check = builtins.isString;
-      merge = lib.concatStrings;
+      merge = mergeOneOption;
     };
 
-    # Like ‘string’, but add newlines between every value.  Useful for
+    # Merge multiple definitions by concatenating them (with the given
-    # configuration file contents.
+    # separator between the values).
-    lines = mkOptionType {
+    separatedString = sep: mkOptionType {
       name = "string";
-      check = lib.traceValIfNot builtins.isString;
+      check = builtins.isString;
-      merge = lib.concatStringsSep "\n";
+      merge = loc: defs: concatStringsSep sep (getValues defs);
     };
 
-    envVar = mkOptionType {
+    lines = separatedString "\n";
-      name = "environment variable";
+    commas = separatedString ",";
-      inherit (string) check;
+    envVar = separatedString ":";
-      merge = lib.concatStringsSep ":";
+
-    };
+    # Deprecated; should not be used because it quietly concatenates
+    # strings, which is usually not what you want.
+    string = separatedString "";
 
     attrs = mkOptionType {
       name = "attribute set";
-      check = lib.traceValIfNot isAttrs;
+      check = isAttrs;
-      merge = fold lib.mergeAttrs {};
+      merge = loc: fold (def: mergeAttrs def.value) {};
     };
 
     # derivation is a reserved keyword.
     package = mkOptionType {
       name = "derivation";
-      check = lib.traceValIfNot isDerivation;
+      check = isDerivation;
+      merge = mergeOneOption;
     };
 
     path = mkOptionType {
       name = "path";
       # Hacky: there is no ‘isPath’ primop.
-      check = lib.traceValIfNot (x: builtins.unsafeDiscardStringContext (builtins.substring 0 1 (toString x)) == "/");
+      check = x: builtins.unsafeDiscardStringContext (builtins.substring 0 1 (toString x)) == "/";
+      merge = mergeOneOption;
     };
 
     # drop this in the future:
-    list = builtins.trace "types.list is deprecated, use types.listOf instead" types.listOf;
+    list = builtins.trace "`types.list' is deprecated; use `types.listOf' instead" types.listOf;
 
-    listOf = elemType: mkOptionType { 
+    listOf = elemType: mkOptionType {
       name = "list of ${elemType.name}s";
-      check = value: lib.traceValIfNot isList value && all elemType.check value;
+      check = value: isList value && all elemType.check value;
-      merge = concatLists;
+      merge = loc: defs:
-      iter = f: path: list: map (elemType.iter f (path + ".*")) list;
+        concatLists (imap (n: def: imap (m: def':
-      fold = op: nul: list: lib.fold (e: l: elemType.fold op l e) nul list;
+          elemType.merge (loc ++ ["[${toString n}-${toString m}]"])
-      docPath = path: elemType.docPath (path + ".*");
+            [{ inherit (def) file; value = def'; }]) def.value) defs);
-      inherit (elemType) hasOptions;
+      getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
-
-      # You cannot define multiple configurations of one entity, therefore
-      # no reason justify to delay properties inside list elements.
-      delayOnGlobalEval = false;
     };
 
     attrsOf = elemType: mkOptionType {
       name = "attribute set of ${elemType.name}s";
-      check = x: lib.traceValIfNot isAttrs x
+      check = x: isAttrs x && all elemType.check (attrValues x);
-        && all elemType.check (lib.attrValues x); 
+      merge = loc: defs:
-      merge = lib.zipAttrsWith (name: elemType.merge);
+        zipAttrsWith (name: elemType.merge (loc ++ [name]))
-      iter = f: path: set: lib.mapAttrs (name: elemType.iter f (path + "." + name)) set;
+          # Push down position info.
-      fold = op: nul: set: fold (e: l: elemType.fold op l e) nul (lib.attrValues set);
+          (map (def: listToAttrs (mapAttrsToList (n: def':
-      docPath = path: elemType.docPath (path + ".<name>");
+            { name = n; value = { inherit (def) file; value = def'; }; }) def.value)) defs);
-      inherit (elemType) hasOptions delayOnGlobalEval;
+      getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
     };
 
     # List or attribute set of ...
     loaOf = elemType:
       let
         convertIfList = defIdx: def:
-          if isList def then
+          if isList def.value then
-            listToAttrs (
+            { inherit (def) file;
-              flip imap def (elemIdx: elem:
+              value = listToAttrs (
-                nameValuePair "unnamed-${toString defIdx}.${toString elemIdx}" elem))
+                imap (elemIdx: elem:
+                  { name = "unnamed-${toString defIdx}.${toString elemIdx}";
+                    value = elem;
+                  }) def.value);
+            }
           else
             def;
         listOnly = listOf elemType;
         attrOnly = attrsOf elemType;
-
       in mkOptionType {
         name = "list or attribute set of ${elemType.name}s";
         check = x:
           if isList x       then listOnly.check x
           else if isAttrs x then attrOnly.check x
-          else lib.traceValIfNot (x: false) x;
+          else false;
-        ## The merge function returns an attribute set
+        merge = loc: defs: attrOnly.merge loc (imap convertIfList defs);
-        merge = defs:
+        getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
-          attrOnly.merge (imap convertIfList defs);
+      };
-        iter = f: path: def:
-          if isList def       then listOnly.iter f path def
-          else if isAttrs def then attrOnly.iter f path def
-          else throw "Unexpected value";
-        fold = op: nul: def:
-          if isList def       then listOnly.fold op nul def
-          else if isAttrs def then attrOnly.fold op nul def
-          else throw "Unexpected value";
-
-        docPath = path: elemType.docPath (path + ".<name?>");
-        inherit (elemType) hasOptions delayOnGlobalEval;
-      }
-    ;
 
     uniq = elemType: mkOptionType {
-      inherit (elemType) name check iter fold docPath hasOptions;
+      inherit (elemType) name check;
-      merge = list:
+      merge = mergeOneOption;
-        if length list == 1 then
+      getSubOptions = elemType.getSubOptions;
-          head list
-        else
-          throw "Multiple definitions of ${elemType.name}. Only one is allowed for this option.";
-    };
-
-    none = elemType: mkOptionType {
-      inherit (elemType) name check iter fold docPath hasOptions;
-      merge = list:
-        throw "No definitions are allowed for this option.";
     };
 
     nullOr = elemType: mkOptionType {
-      inherit (elemType) name merge docPath hasOptions;
+      name = "null or ${elemType.name}";
       check = x: builtins.isNull x || elemType.check x;
-      iter = f: path: v: if v == null then v else elemType.iter f path v;
+      merge = loc: defs:
-      fold = op: nul: v: if v == null then nul else elemType.fold op nul v;
+        let nrNulls = count (def: isNull def.value) defs; in
+        if nrNulls == length defs then null
+        else if nrNulls != 0 then
+          throw "The option `${showOption loc}' is defined both null and not null, in ${showFiles (getFiles defs)}."
+        else elemType.merge loc defs;
+      getSubOptions = elemType.getSubOptions;
     };
 
     functionTo = elemType: mkOptionType {
       name = "function that evaluates to a(n) ${elemType.name}";
-      check = lib.traceValIfNot builtins.isFunction;
+      check = builtins.isFunction;
-      merge = fns:
+      merge = loc: defs:
-        args: elemType.merge (map (fn: fn args) fns);
+        fnArgs: elemType.merge loc (map (fn: { inherit (fn) file; value = fn.value fnArgs; }) defs);
-      # These are guesses, I don't fully understand iter, fold, delayOnGlobalEval
+      getSubOptions = elemType.getSubOptions;
-      iter = f: path: v:
-        args: elemType.iter f path (v args);
-      fold = op: nul: v:
-        args: elemType.fold op nul (v args);
-      inherit (elemType) delayOnGlobalEval;
-      hasOptions = false;
     };
 
-    # usually used with listOf, attrsOf, loaOf like this:
+    submodule = opts:
-    # users = mkOption {
+      let
-    #   type = loaOf optionSet;
+        opts' = toList opts;
-    #
+        inherit (import ./modules.nix) evalModules;
-    #   # you can omit the list if there is one element only
+      in
-    #   options = [ {
+      mkOptionType rec {
-    #     name = mkOption {
+        name = "submodule";
-    #       description = "name of the user"
+        check = x: isAttrs x || builtins.isFunction x;
-    #       ...
+        merge = loc: defs:
-    #     };
+          let
-    #     # more options here
+            coerce = def: if builtins.isFunction def then def else { config = def; };
-    #   } { more options } ];
+            modules = opts' ++ map (def: { _file = def.file; imports = [(coerce def.value)]; }) defs;
-    # }
+          in (evalModules { inherit modules; args.name = last loc; prefix = loc; }).config;
-    # TODO: !!! document passing options as an argument to optionSet,
+        getSubOptions = prefix: (evalModules
-    # deprecate the current approach.
+          { modules = opts'; inherit prefix;
+            # FIXME: hack to get shit to evaluate.
+            args = { name = ""; }; }).options;
+      };
+
+    # Obsolete alternative to configOf.  It takes its option
+    # declarations from the ‘options’ attribute of containing option
+    # declaration.
     optionSet = mkOptionType {
-      name = "option set";
+      name = /* builtins.trace "types.optionSet is deprecated; use types.submodule instead" */ "option set";
-      # merge is done in "options.nix > addOptionMakeUp > handleOptionSets"
-      merge = lib.id;
-      check = x: isAttrs x || builtins.isFunction x;
-      hasOptions = true;
-      delayOnGlobalEval = true;
     };
 
+    # Augment the given type with an additional type check function.
+    addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
+
   };
 
 }

nixos/default.nix

@@ -9,7 +9,7 @@ let
     modules = [ configuration ];
   };
 
-  inherit (eval) config pkgs;
+  inherit (eval) pkgs;
 
   # This is for `nixos-rebuild build-vm'.
   vmConfig = (import ./lib/eval-config.nix {
@@ -30,9 +30,9 @@ let
 in
 
 {
-  inherit eval config;
+  inherit (eval) config options;
 
-  system = config.system.build.toplevel;
+  system = eval.config.system.build.toplevel;
 
   vm = vmConfig.system.build.vm;
 

nixos/doc/manual/configuration.xml

@@ -7,7 +7,7 @@
 <para>This chapter describes how to configure various aspects of a
 NixOS machine through the configuration file
 <filename>/etc/nixos/configuration.nix</filename>.  As described in
-<xref linkend="sec-changing-config" />, changes to that file only take
+<xref linkend="sec-changing-config" />, changes to this file only take
 effect after you run <command>nixos-rebuild</command>.</para>
 
 
@@ -15,7 +15,703 @@ effect after you run <command>nixos-rebuild</command>.</para>
 
 <section xml:id="sec-configuration-syntax"><title>Configuration syntax</title>
 
-<para>TODO</para>
+<section><title>The basics</title>
+
+<para>The NixOS configuration file
+<filename>/etc/nixos/configuration.nix</filename> is actually a
+<emphasis>Nix expression</emphasis>, which is the Nix package
+manager’s purely functional language for describing how to build
+packages and configurations.  This means you have all the expressive
+power of that language at your disposal, including the ability to
+abstract over common patterns, which is very useful when managing
+complex systems.  The syntax and semantics of the Nix language are
+fully described in the <link
+xlink:href="http://nixos.org/nix/manual/#chap-writing-nix-expressions">Nix
+manual</link>, but here we give a short overview of the most important
+constructs useful in NixOS configuration files.</para>
+
+<para>The NixOS configuration file generally looks like this:
+
+<programlisting>
+{ config, pkgs, ... }:
+
+{ <replaceable>option definitions</replaceable>
+}
+</programlisting>
+
+The first line (<literal>{ config, pkgs, ... }:</literal>) denotes
+that this is actually a function that takes at least the two arguments
+ <varname>config</varname> and <varname>pkgs</varname>.  (These are
+explained later.)  The function returns a <emphasis>set</emphasis> of
+option definitions (<literal>{ <replaceable>...</replaceable> }</literal>).  These definitions have the
+form <literal><replaceable>name</replaceable> =
+<replaceable>value</replaceable></literal>, where
+<replaceable>name</replaceable> is the name of an option and
+<replaceable>value</replaceable> is its value.  For example,
+
+<programlisting>
+{ config, pkgs, ... }:
+
+{ services.httpd.enable = true;
+  services.httpd.adminAddr = "alice@example.org";
+  services.httpd.documentRoot = "/webroot";
+}
+</programlisting>
+
+defines a configuration with three option definitions that together
+enable the Apache HTTP Server with <filename>/webroot</filename> as
+the document root.</para>
+
+<para>Sets can be nested, and in fact dots in option names are
+shorthand for defining a set containing another set.  For instance,
+<option>services.httpd.enable</option> defines a set named
+<varname>services</varname> that contains a set named
+<varname>httpd</varname>, which in turn contains an option definition
+named <varname>enable</varname> with value <literal>true</literal>.
+This means that the example above can also be written as:
+
+<programlisting>
+{ config, pkgs, ... }:
+
+{ services = {
+    httpd = {
+      enable = true;
+      adminAddr = "alice@example.org";
+      documentRoot = "/webroot";
+    };
+  };
+}
+</programlisting>
+
+which may be more convenient if you have lots of option definitions
+that share the same prefix (such as
+<literal>services.httpd</literal>).</para>
+
+<para>NixOS checks your option definitions for correctness.  For
+instance, if you try to define an option that doesn’t exist (that is,
+doesn’t have a corresponding <emphasis>option declaration</emphasis>),
+<command>nixos-rebuild</command> will give an error like:
+<screen>
+The option `services.httpd.enabl' defined in `/etc/nixos/configuration.nix' does not exist.
+</screen>
+Likewise, values in option definitions must have a correct type.  For
+instance, <option>services.httpd.enable</option> must be a Boolean
+(<literal>true</literal> or <literal>false</literal>).  Trying to give
+it a value of another type, such as a string, will cause an error:
+<screen>
+The option value `services.httpd.enable' in `/etc/nixos/configuration.nix' is not a boolean.
+</screen>
+
+</para>
+
+<para>Options have various types of values.  The most important are:
+
+<variablelist>
+  <varlistentry>
+    <term>Strings</term>
+    <listitem>
+      <para>Strings are enclosed in double quotes, e.g.
+
+<programlisting>
+networking.hostName = "dexter";
+</programlisting>
+
+      Special characters can be escaped by prefixing them with a
+      backslash (e.g. <literal>\"</literal>).</para>
+
+      <para>Multi-line strings can be enclosed in <emphasis>double
+      single quotes</emphasis>, e.g.
+
+<programlisting>
+networking.extraHosts =
+  ''
+    127.0.0.2 other-localhost
+    10.0.0.1 server
+  '';
+</programlisting>
+
+      The main difference is that preceding whitespace is
+      automatically stripped from each line, and that characters like
+      <literal>"</literal> and <literal>\</literal> are not special
+      (making it more convenient for including things like shell
+      code).</para>
+    </listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term>Booleans</term>
+    <listitem>
+      <para>These can be <literal>true</literal> or
+      <literal>false</literal>, e.g.
+
+<programlisting>
+networking.firewall.enable = true;
+networking.firewall.allowPing = false;
+</programlisting>
+      </para>
+    </listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term>Integers</term>
+    <listitem>
+      <para>For example,
+
+<programlisting>
+boot.kernel.sysctl."net.ipv4.tcp_keepalive_time" = 60;
+</programlisting>
+
+      (Note that here the attribute name
+      <literal>net.ipv4.tcp_keepalive_time</literal> is enclosed in
+      quotes to prevent it from being interpreted as a set named
+      <literal>net</literal> containing a set named
+      <literal>ipv4</literal>, and so on.  This is because it’s not a
+      NixOS option but the literal name of a Linux kernel
+      setting.)</para>
+    </listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term>Sets</term>
+    <listitem>
+      <para>Sets were introduced above.  They are name/value pairs
+      enclosed in braces, as in the option definition
+
+<programlisting>
+fileSystems."/boot" =
+  { device = "/dev/sda1";
+    fsType = "ext4";
+    options = "rw,data=ordered,relatime";
+  };
+</programlisting>
+      </para>
+    </listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term>Lists</term>
+    <listitem>
+      <para>The important thing to note about lists is that list
+      elements are separated by whitespace, like this:
+
+<programlisting>
+boot.kernelModules = [ "fuse" "kvm-intel" "coretemp" ];
+</programlisting>
+
+      List elements can be any other type, e.g. sets:
+
+<programlisting>
+swapDevices = [ { device = "/dev/disk/by-label/swap"; } ];
+</programlisting>
+      </para>
+    </listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term>Packages</term>
+    <listitem>
+      <para>Usually, the packages you need are already part of the Nix
+      Packages collection, which is a set that can be accessed through
+      the function argument <varname>pkgs</varname>.  Typical uses:
+
+<programlisting>
+environment.systemPackages =
+  [ pkgs.thunderbird
+    pkgs.emacs
+  ];
+
+postgresql.package = pkgs.postgresql90;
+</programlisting>
+
+      The latter option definition changes the default PostgreSQL
+      package used by NixOS’s PostgreSQL service to 9.0.  For more
+      information on packages, including how to add new ones, see
+      <xref linkend="sec-custom-packages"/>.</para>
+    </listitem>
+  </varlistentry>
+
+</variablelist>
+
+</para>
+
+</section>
+
+
+<section><title>Abstractions</title>
+
+<para>If you find yourself repeating yourself over and over, it’s time
+to abstract.  Take, for instance, this Apache HTTP Server configuration:
+
+<programlisting>
+{
+  services.httpd.virtualHosts =
+    [ { hostName = "example.org";
+        documentRoot = "/webroot";
+        adminAddr = "alice@example.org";
+        enableUserDir = true;
+      }
+      { hostName = "example.org";
+        documentRoot = "/webroot";
+        adminAddr = "alice@example.org";
+        enableUserDir = true;
+        enableSSL = true;
+        sslServerCert = "/root/ssl-example-org.crt";
+        sslServerKey = "/root/ssl-example-org.key";
+      }
+    ];
+}
+</programlisting>
+
+It defines two virtual hosts with nearly identical configuration; the
+only difference is that the second one has SSL enabled.  To prevent
+this duplication, we can use a <literal>let</literal>:
+
+<programlisting>
+let
+  exampleOrgCommon =
+    { hostName = "example.org";
+      documentRoot = "/webroot";
+      adminAddr = "alice@example.org";
+      enableUserDir = true;
+    };
+in
+{
+  services.httpd.virtualHosts =
+    [ exampleOrgCommon
+      (exampleOrgCommon // {
+        enableSSL = true;
+        sslServerCert = "/root/ssl-example-org.crt";
+        sslServerKey = "/root/ssl-example-org.key";
+      })
+    ];
+}
+</programlisting>
+
+The <literal>let exampleOrgCommon =
+<replaceable>...</replaceable></literal> defines a variable named
+<literal>exampleOrgCommon</literal>.  The <literal>//</literal>
+operator merges two attribute sets, so the configuration of the second
+virtual host is the set <literal>exampleOrgCommon</literal> extended
+with the SSL options.</para>
+
+<para>You can write a <literal>let</literal> wherever an expression is
+allowed.  Thus, you also could have written:
+
+<programlisting>
+{
+  services.httpd.virtualHosts =
+    let exampleOrgCommon = <replaceable>...</replaceable>; in
+    [ exampleOrgCommon
+      (exampleOrgCommon // { <replaceable>...</replaceable> })
+    ];
+}
+</programlisting>
+
+but not <literal>{ let exampleOrgCommon =
+<replaceable>...</replaceable>; in <replaceable>...</replaceable>;
+}</literal> since attributes (as opposed to attribute values) are not
+expressions.</para>
+
+<para><emphasis>Functions</emphasis> provide another method of
+abstraction.  For instance, suppose that we want to generate lots of
+different virtual hosts, all with identical configuration except for
+the host name.  This can be done as follows:
+
+<programlisting>
+{
+  services.httpd.virtualHosts =
+    let
+      makeVirtualHost = name:
+        { hostName = name;
+          documentRoot = "/webroot";
+          adminAddr = "alice@example.org";
+        };
+    in
+      [ (makeVirtualHost "example.org")
+        (makeVirtualHost "example.com")
+        (makeVirtualHost "example.gov")
+        (makeVirtualHost "example.nl")
+      ];
+}
+</programlisting>
+
+Here, <varname>makeVirtualHost</varname> is a function that takes a
+single argument <literal>name</literal> and returns the configuration
+for a virtual host.  That function is then called for several names to
+produce the list of virtual host configurations.</para>
+
+<para>We can further improve on this by using the function
+<varname>map</varname>, which applies another function to every
+element in a list:
+
+<programlisting>
+{
+  services.httpd.virtualHosts =
+    let
+      makeVirtualHost = <replaceable>...</replaceable>;
+    in map makeVirtualHost
+      [ "example.org" "example.com" "example.gov" "example.nl" ];
+}
+</programlisting>
+
+(The function <literal>map</literal> is called a
+<emphasis>higher-order function</emphasis> because it takes another
+function as an argument.)</para>
+
+<para>What if you need more than one argument, for instance, if we
+want to use a different <literal>documentRoot</literal> for each
+virtual host?  Then we can make <varname>makeVirtualHost</varname> a
+function that takes a <emphasis>set</emphasis> as its argument, like this:
+
+<programlisting>
+{
+  services.httpd.virtualHosts =
+    let
+      makeVirtualHost = { name, root }:
+        { hostName = name;
+          documentRoot = root;
+          adminAddr = "alice@example.org";
+        };
+    in map makeVirtualHost
+      [ { name = "example.org"; root = "/sites/example.org"; }
+        { name = "example.com"; root = "/sites/example.com"; }
+        { name = "example.gov"; root = "/sites/example.gov"; }
+        { name = "example.nl"; root = "/sites/example.nl"; }
+      ];
+}
+</programlisting>
+
+But in this case (where every root is a subdirectory of
+<filename>/sites</filename> named after the virtual host), it would
+have been shorter to define <varname>makeVirtualHost</varname> as
+<programlisting>
+makeVirtualHost = name:
+  { hostName = name;
+    documentRoot = "/sites/${name}";
+    adminAddr = "alice@example.org";
+  };
+</programlisting>
+
+Here, the construct
+<literal>${<replaceable>...</replaceable>}</literal> allows the result
+of an expression to be spliced into a string.</para>
+
+</section>
+
+
+<section><title>Modularity</title>
+
+<para>The NixOS configuration mechanism is modular.  If your
+<filename>configuration.nix</filename> becomes too big, you can split
+it into multiple files.  Likewise, if you have multiple NixOS
+configurations (e.g. for different computers) with some commonality,
+you can move the common configuration into a shared file.</para>
+
+<para>Modules have exactly the same syntax as
+<filename>configuration.nix</filename>.  In fact,
+<filename>configuration.nix</filename> is itself a module.  You can
+use other modules by including them from
+<filename>configuration.nix</filename>, e.g.:
+
+<programlisting>
+{ config, pkgs, ... }:
+
+{ imports = [ ./vpn.nix ./kde.nix ];
+  services.httpd.enable = true;
+  environment.systemPackages = [ pkgs.emacs ];
+  <replaceable>...</replaceable>
+}
+</programlisting>
+
+Here, we include two modules from the same directory,
+<filename>vpn.nix</filename> and <filename>kde.nix</filename>.  The
+latter might look like this:
+
+<programlisting>
+{ config, pkgs, ... }:
+
+{ services.xserver.enable = true;
+  services.xserver.displayManager.kdm.enable = true;
+  services.xserver.desktopManager.kde4.enable = true;
+  environment.systemPackages = [ pkgs.kde4.kscreensaver ];
+}
+</programlisting>
+
+Note that both <filename>configuration.nix</filename> and
+<filename>kde.nix</filename> define the option
+<option>environment.systemPackages</option>.  When multiple modules
+define an option, NixOS will try to <emphasis>merge</emphasis> the
+definitions.  In the case of
+<option>environment.systemPackages</option>, that’s easy: the lists of
+packages can simply be concatenated.  For other types of options, a
+merge may not be possible: for instance, if two modules define
+<option>services.httpd.adminAddr</option>,
+<command>nixos-rebuild</command> will give an error:
+
+<screen>
+The unique option `services.httpd.adminAddr' is defined multiple times, in `/etc/nixos/httpd.nix' and `/etc/nixos/configuration.nix'.
+</screen>
+
+When that happens, it’s possible to force one definition take
+precedence over the others:
+
+<programlisting>
+services.httpd.adminAddr = pkgs.lib.mkForce "bob@example.org";
+</programlisting>
+
+</para>
+
+<para>When using multiple modules, you may need to access
+configuration values defined in other modules.  This is what the
+<varname>config</varname> function argument is for: it contains the
+complete, merged system configuration.  That is,
+<varname>config</varname> is the result of combining the
+configurations returned by every module<footnote><para>If you’re
+wondering how it’s possible that the (indirect)
+<emphasis>result</emphasis> of a function is passed as an
+<emphasis>input</emphasis> to that same function: that’s because Nix
+is a “lazy” language — it only computes values when they are needed.
+This works as long as no individual configuration value depends on
+itself.</para></footnote>.  For example, here is a module that adds
+some packages to <option>environment.systemPackages</option> only if
+<option>services.xserver.enable</option> is set to
+<literal>true</literal> somewhere else:
+
+<programlisting>
+{ config, pkgs, ... }:
+
+{ environment.systemPackages =
+    if config.services.xserver.enable then
+      [ pkgs.firefox
+        pkgs.thunderbird
+      ]
+    else
+      [ ];
+}
+</programlisting>
+
+</para>
+
+<para>With multiple modules, it may not be obvious what the final
+value of a configuration option is.  The command
+<option>nixos-option</option> allows you to find out:
+
+<screen>
+$ nixos-option services.xserver.enable
+true
+
+$ nixos-option boot.kernelModules
+[ "tun" "ipv6" "loop" <replaceable>...</replaceable> ]
+</screen>
+
+Interactive exploration of the configuration is possible using
+<command
+xlink:href="https://github.com/edolstra/nix-repl">nix-repl</command>,
+a read-eval-print loop for Nix expressions.  It’s not installed by
+default; run <literal>nix-env -i nix-repl</literal> to get it.  A
+typical use:
+
+<screen>
+$ nix-repl '&lt;nixos>'
+
+nix-repl> config.networking.hostName
+"mandark"
+
+nix-repl> map (x: x.hostName) config.services.httpd.virtualHosts
+[ "example.org" "example.gov" ]
+</screen>
+
+</para>
+
+</section>
+
+
+<section><title>Syntax summary</title>
+
+<para>Below is a summary of the most important syntactic constructs in
+the Nix expression language.  It’s not complete.  In particular, there
+are many other built-in functions.  See the <link
+xlink:href="http://nixos.org/nix/manual/#chap-writing-nix-expressions">Nix
+manual</link> for the rest.</para>
+
+<informaltable frame='none'>
+  <tgroup cols='2'>
+    <colspec colname='c1' rowsep='1' colsep='1' />
+    <colspec colname='c2' rowsep='1' />
+    <thead>
+      <row>
+        <entry>Example</entry>
+        <entry>Description</entry>
+      </row>
+    </thead>
+    <tbody>
+
+      <row>
+        <entry namest="c1" nameend="c2"><emphasis>Basic values</emphasis></entry>
+      </row>
+      <row>
+        <entry><literal>"Hello world"</literal></entry>
+        <entry>A string</entry>
+      </row>
+      <row>
+        <entry><literal>"${pkgs.bash}/bin/sh"</literal></entry>
+        <entry>A string containing an expression (expands to <literal>"/nix/store/<replaceable>hash</replaceable>-bash-<replaceable>version</replaceable>/bin/sh"</literal>)</entry>
+      </row>
+      <row>
+        <entry><literal>true</literal>, <literal>false</literal></entry>
+        <entry>Booleans</entry>
+      </row>
+      <row>
+        <entry><literal>123</literal></entry>
+        <entry>An integer</entry>
+      </row>
+      <row>
+        <entry><literal>./foo.png</literal></entry>
+        <entry>A path (relative to the containing Nix expression)</entry>
+      </row>
+
+      <row>
+        <entry namest="c1" nameend="c2"><emphasis>Compound values</emphasis></entry>
+      </row>
+      <row>
+        <entry><literal>{ x = 1; y = 2; }</literal></entry>
+        <entry>An set with attributes names <literal>x</literal> and <literal>y</literal></entry>
+      </row>
+      <row>
+        <entry><literal>{ foo.bar = 1; }</literal></entry>
+        <entry>A nested set, equivalent to <literal>{ foo = { bar = 1; }; }</literal></entry>
+      </row>
+      <row>
+        <entry><literal>rec { x = "bla"; y = x + "bar"; }</literal></entry>
+        <entry>A recursive set, equivalent to <literal>{ x = "foo"; y = "foobar"; }</literal></entry>
+      </row>
+      <row>
+        <entry><literal>[ "foo" "bar" ]</literal></entry>
+        <entry>A list with two elements</entry>
+      </row>
+
+      <row>
+        <entry namest="c1" nameend="c2"><emphasis>Operators</emphasis></entry>
+      </row>
+      <row>
+        <entry><literal>"foo" + "bar"</literal></entry>
+        <entry>String concatenation</entry>
+      </row>
+      <row>
+        <entry><literal>1 + 2</literal></entry>
+        <entry>Integer addition</entry>
+      </row>
+      <row>
+        <entry><literal>"foo" == "f" + "oo"</literal></entry>
+        <entry>Equality test (evaluates to <literal>true</literal>)</entry>
+      </row>
+      <row>
+        <entry><literal>"foo" != "bar"</literal></entry>
+        <entry>Inequality test (evaluates to <literal>true</literal>)</entry>
+      </row>
+      <row>
+        <entry><literal>!true</literal></entry>
+        <entry>Boolean negation</entry>
+      </row>
+      <row>
+        <entry><literal>{ x = 1; y = 2; }.x</literal></entry>
+        <entry>Attribute selection (evaluates to <literal>1</literal>)</entry>
+      </row>
+      <row>
+        <entry><literal>{ x = 1; y = 2; }.z or 3</literal></entry>
+        <entry>Attribute selection with default (evaluates to <literal>3</literal>)</entry>
+      </row>
+      <row>
+        <entry><literal>{ x = 1; y = 2; } // { z = 3; }</literal></entry>
+        <entry>Merge two sets (attributes in the right-hand set taking precedence)</entry>
+      </row>
+
+      <row>
+        <entry namest="c1" nameend="c2"><emphasis>Control structures</emphasis></entry>
+      </row>
+      <row>
+        <entry><literal>if 1 + 1 == 2 then "yes!" else "no!"</literal></entry>
+        <entry>Conditional expression</entry>
+      </row>
+      <row>
+        <entry><literal>assert 1 + 1 == 2; "yes!"</literal></entry>
+        <entry>Assertion check (evaluates to <literal>"yes!"</literal>)</entry>
+      </row>
+      <row>
+        <entry><literal>let x = "foo"; y = "bar"; in x + y</literal></entry>
+        <entry>Variable definition</entry>
+      </row>
+      <row>
+        <entry><literal>with pkgs.lib; head [ 1 2 3 ]</literal></entry>
+        <entry>Add all attributes from the given set to the scope
+        (evaluates to <literal>1</literal>)</entry>
+      </row>
+
+      <row>
+        <entry namest="c1" nameend="c2"><emphasis>Functions (lambdas)</emphasis></entry>
+      </row>
+      <row>
+        <entry><literal>x: x + 1</literal></entry>
+        <entry>A function that expects an integer and returns it increased by 1</entry>
+      </row>
+      <row>
+        <entry><literal>(x: x + 1) 100</literal></entry>
+        <entry>A function call (evaluates to 101)</entry>
+      </row>
+      <row>
+        <entry><literal>let inc = x: x + 1; in inc (inc (inc 100))</literal></entry>
+        <entry>A function bound to a variable and subsequently called by name (evaluates to 103)</entry>
+      </row>
+      <row>
+        <entry><literal>{ x, y }: x + y</literal></entry>
+        <entry>A function that expects a set with required attributes
+        <literal>x</literal> and <literal>y</literal> and concatenates
+        them</entry>
+      </row>
+      <row>
+        <entry><literal>{ x, y ? "bar" }: x + y</literal></entry>
+        <entry>A function that expects a set with required attribute
+        <literal>x</literal> and optional <literal>y</literal>, using
+        <literal>"bar"</literal> as default value for
+        <literal>y</literal></entry>
+      </row>
+      <row>
+        <entry><literal>{ x, y, ... }: x + y</literal></entry>
+        <entry>A function that expects a set with required attributes
+        <literal>x</literal> and <literal>y</literal> and ignores any
+        other attributes</entry>
+      </row>
+      <row>
+        <entry><literal>{ x, y } @ args: x + y</literal></entry>
+        <entry>A function that expects a set with required attributes
+        <literal>x</literal> and <literal>y</literal>, and binds the
+        whole set to <literal>args</literal></entry>
+      </row>
+
+      <row>
+        <entry namest="c1" nameend="c2"><emphasis>Built-in functions</emphasis></entry>
+      </row>
+      <row>
+        <entry><literal>import ./foo.nix</literal></entry>
+        <entry>Load and return Nix expression in given file</entry>
+      </row>
+      <row>
+        <entry><literal>map (x: x + x) [ 1 2 3 ]</literal></entry>
+        <entry>Apply a function to every element of a list (evaluates to <literal>[ 2 4 6 ]</literal>)</entry>
+      </row>
+      <!--
+      <row>
+        <entry><literal>throw "Urgh"</literal></entry>
+        <entry>Raise an error condition</entry>
+      </row>
+      -->
+
+    </tbody>
+  </tgroup>
+</informaltable>
+
+</section>
+
 
 </section>
 
@@ -170,7 +866,7 @@ recursion.)</para>
 
 </section>
 
-<section><title>Adding custom packages</title>
+<section xml:id="sec-custom-packages"><title>Adding custom packages</title>
 
 <para>It’s possible that a package you need is not available in NixOS.
 In that case, you can do two things.  First, you can clone the Nixpkgs
@@ -316,7 +1012,7 @@ manpage or the Nix manual.</para>
 
 <!--===============================================================-->
 
-<section><title>User management</title>
+<section xml:id="sec-user-management"><title>User management</title>
 
 <para>NixOS supports both declarative and imperative styles of user
 management.  In the declarative style, users are specified in

nixos/doc/manual/installation.xml

@@ -18,6 +18,33 @@ details, see the <link
 xlink:href="https://nixos.org/wiki/Installing_NixOS_from_a_USB_stick">NixOS
 Wiki</link>.</para>
 
+<para>As an alternative to installing NixOS yourself, you can get a
+running NixOS system through several other means:
+
+<itemizedlist>
+  <listitem>
+    <para>Using virtual appliances in Open Virtualization Format (OVF)
+    that can be imported into VirtualBox.  These are available from
+    the <link xlink:href="http://nixos.org/nixos/download.html">NixOS
+    homepage</link>.</para>
+  </listitem>
+  <listitem>
+    <para>Using AMIs for Amazon’s EC2.  To find one for your region
+    and instance type, please refer to the <link
+    xlink:href="https://github.com/NixOS/nixops/blob/master/nix/ec2-amis.nix">list
+    of most recent AMIs</link>.</para>
+  </listitem>
+  <listitem>
+    <para>Using NixOps, the NixOS-based cloud deployment tool, which
+    allows you to provision VirtualBox and EC2 NixOS instances from
+    declarative specifications.  Check out the <link
+    xlink:href="https://github.com/NixOS/nixops">NixOps
+    homepage</link> for details.</para>
+  </listitem>
+</itemizedlist>
+
+</para>
+
 </section>
 
 
@@ -62,9 +89,14 @@ Wiki</link>.</para>
     <listitem><para>For initialising Ext4 partitions:
     <command>mkfs.ext4</command>.  It is recommended that you assign a
     unique symbolic label to the file system using the option
-    <option>-L <replaceable>label</replaceable></option>.  This will
+    <option>-L <replaceable>label</replaceable></option>, since this
-    make the file system configuration independent from device
+    makes the file system configuration independent from device
-    changes.</para></listitem>
+    changes.  For example:
+
+<screen>
+$ mkfs.ext4 -L nixos /dev/sda1</screen>
+
+    </para></listitem>
 
     <listitem><para>For creating swap partitions:
     <command>mkswap</command>.  Again it’s recommended to assign a
@@ -97,6 +129,12 @@ $ mount /dev/disk/by-label/nixos /mnt
 
   </para></listitem>
 
+  <listitem><para>If your machine has a limited amount of memory, you
+  may want to activate swap devices now (<command>swapon
+  <replaceable>device</replaceable></command>).  The installer (or
+  rather, the build actions that it may spawn) may need quite a bit of
+  RAM, depending on your configuration.</para></listitem>
+
   <listitem>
 
     <para>You now need to create a file
@@ -161,28 +199,16 @@ $ nano /mnt/etc/nixos/configuration.nix
 
   </listitem>
 
-  <listitem><para>If your machine has a limited amount of memory, you
-  may want to activate swap devices now (<command>swapon
-  <replaceable>device</replaceable></command>).  The installer (or
-  rather, the build actions that it may spawn) may need quite a bit of
-  RAM, depending on your configuration.</para></listitem>
-
-  <!--
-  <listitem><para>Optionally, you can run
-
-<screen>
-$ nixos-checkout</screen>
-
-  to make the installer use the latest NixOS/Nixpkgs sources from the
-  Git repository, rather than the sources on CD.</para></listitem>
-  -->
-
   <listitem><para>Do the installation:
 
 <screen>
 $ nixos-install</screen>
 
-    Cross fingers.</para></listitem>
+    Cross fingers.  If this fails due to a temporary problem (such as
+    a network issue while downloading binaries from the NixOS binary
+    cache), you can just re-run <command>nixos-install</command>.
+    Otherwise, fix your <filename>configuration.nix</filename> and
+    then re-run <command>nixos-install</command>.</para></listitem>
 
   <listitem><para>If everything went well:
 
@@ -194,7 +220,7 @@ $ reboot</screen>
   <listitem>
 
     <para>You should now be able to boot into the installed NixOS.
-    The Grub boot menu shows a list of <emphasis>available
+    The GRUB boot menu shows a list of <emphasis>available
     configurations</emphasis> (initially just one).  Every time you
     change the NixOS configuration (see <xref
     linkend="sec-changing-config" />), a new item appears in the menu.
@@ -229,26 +255,28 @@ $ nix-env -i w3m</screen>
 
 </orderedlist>
 
-<para><xref linkend="ex-install-sequence" /> shows a typical sequence
+<para>To summarise, <xref linkend="ex-install-sequence" /> shows a
-of commands for installing NixOS on an empty hard drive (here
+typical sequence of commands for installing NixOS on an empty hard
-<filename>/dev/sda</filename>).  <xref linkend="ex-config" /> shows a
+drive (here <filename>/dev/sda</filename>).  <xref linkend="ex-config"
-corresponding configuration Nix expression.</para>
+/> shows a corresponding configuration Nix expression.</para>
 
 <example xml:id='ex-install-sequence'><title>Commands for installing NixOS on <filename>/dev/sda</filename></title>
 <screen>
-$ fdisk /dev/sda <lineannotation>(or whatever device you want to install on)</lineannotation>
+$ fdisk /dev/sda # <lineannotation>(or whatever device you want to install on)</lineannotation>
-$ mkfs.ext4 -L nixos /dev/sda1 <lineannotation>(idem)</lineannotation>
+$ mkfs.ext4 -L nixos /dev/sda1
-$ mkswap -L swap /dev/sda2 <lineannotation>(idem)</lineannotation>
+$ mkswap -L swap /dev/sda2
-$ mount LABEL=nixos /mnt
+$ swapon /dev/sda2
-$ nixos-generate-config
+$ mount /dev/disk/by-label/nixos /mnt
+$ nixos-generate-config --root /mnt
 $ nano /mnt/etc/nixos/configuration.nix
-<lineannotation>(in particular, set the fileSystems and swapDevices options)</lineannotation>
 $ nixos-install
 $ reboot</screen>
 </example>
 
 <example xml:id='ex-config'><title>NixOS configuration</title>
 <screen>
+{ config, pkgs, ... }:
+
 {
   imports =
     [ # Include the results of the hardware scan.
@@ -257,14 +285,12 @@ $ reboot</screen>
 
   boot.loader.grub.device = "/dev/sda";
 
-  # Note: setting fileSystems and swapDevices is generally not
+  # Note: setting fileSystems is generally not
-  # necessary, since nixos-generate-config has set them automatically
+  # necessary, since nixos-generate-config figures them out
-  # in hardware-configuration.nix.
+  # automatically in hardware-configuration.nix.
-  fileSystems."/".device = "/dev/disk/by-label/nixos";
+  #fileSystems."/".device = "/dev/disk/by-label/nixos";
-
-  swapDevices =
-    [ { device = "/dev/disk/by-label/swap"; } ];
 
+  # Enable the OpenSSH server.
   services.sshd.enable = true;
 }</screen>
 </example>
@@ -290,6 +316,10 @@ to build the new configuration, make it the default configuration for
 booting, and try to realise the configuration in the running system
 (e.g., by restarting system services).</para>
 
+<warning><para>These commands must be executed as root, so you should
+either run them from a root shell or by prefixing them with
+<literal>sudo -i</literal>.</para></warning>
+
 <para>You can also do
 
 <screen>
@@ -309,6 +339,18 @@ to build the configuration and make it the boot default, but not
 switch to it now (so it will only take effect after the next
 reboot).</para>
 
+<para>You can make your configuration show up in a different submenu
+of the GRUB 2 boot screen by giving it a different <emphasis>profile
+name</emphasis>, e.g.
+
+<screen>
+$ nixos-rebuild switch -p test </screen>
+
+which causes the new configuration (and previous ones created using
+<literal>-p test</literal>) to show up in the GRUB submenu “NixOS -
+Profile 'test'”.  This can be useful to separate test configurations
+from “stable” configurations.</para>
+
 <para>Finally, you can do
 
 <screen>
@@ -319,7 +361,7 @@ whether everything compiles cleanly.</para>
 
 <para>If you have a machine that supports hardware virtualisation, you
 can also test the new configuration in a sandbox by building and
-running a <emphasis>virtual machine</emphasis> that contains the
+running a QEMU <emphasis>virtual machine</emphasis> that contains the
 desired configuration.  Just do
 
 <screen>
@@ -334,7 +376,6 @@ available.</para>
 </section>
 
 
-
 <!--===============================================================-->
 
 <section xml:id="sec-upgrading">
@@ -342,28 +383,86 @@ available.</para>
 <title>Upgrading NixOS</title>
 
 <para>The best way to keep your NixOS installation up to date is to
-use the <literal>nixos-unstable</literal> channel.  (A channel is a
+use one of the NixOS <emphasis>channels</emphasis>.  A channel is a
 Nix mechanism for distributing Nix expressions and associated
-binaries.)  The NixOS channel is updated automatically from NixOS’s
+binaries.  The NixOS channels are updated automatically from NixOS’s
-Git repository after running certain tests and building most
+Git repository after certain tests have passed and all packages have
-packages.</para>
+been built.  These channels are:
 
-<para>NixOS automatically subscribes you to the NixOS channel.  If for
+<itemizedlist>
-some reason this is not the case, just do
+  <listitem>
+    <para>Stable channels, such as <literal
+    xlink:href="http://nixos.org/channels/nixos-13.10">nixos-13.10</literal>.
+    These only get conservative bug fixes and package upgrades.  For
+    instance, a channel update may cause the Linux kernel on your
+    system to be upgraded from 3.4.66 to 3.4.67 (a minor bug fix), but
+    not from 3.4.<replaceable>x</replaceable> to
+    3.11.<replaceable>x</replaceable> (a major change that has the
+    potential to break things).  Stable channels are generally
+    maintained until the next stable branch is created.</para>
+  </listitem>
+  <listitem>
+    <para>The unstable channel, <literal
+    xlink:href="http://nixos.org/channels/nixos-unstable">nixos-unstable</literal>.
+    This corresponds to NixOS’s main development branch, and may thus
+    see radical changes between channel updates.  It’s not recommended
+    for production systems.</para>
+  </listitem>
+</itemizedlist>
+
+To see what channels are available, go to <link
+xlink:href="http://nixos.org/channels"/>.  (Note that the URIs of the
+various channels redirect to a directory that contains the channel’s
+latest version and includes ISO images and VirtualBox
+appliances.)</para>
+
+<para>When you first install NixOS, you’re automatically subscribed to
+the NixOS channel that corresponds to your installation source.   For
+instance, if you installed from a 13.10 ISO, you will be subscribed to
+the <literal>nixos-13.10</literal> channel.  To see which NixOS
+channel you’re subscribed to, run the following as root:
 
 <screen>
-$ nix-channel --add http://nixos.org/channels/nixos-unstable
+$ nix-channel --list | grep nixos
+nixos https://nixos.org/channels/nixos-unstable
 </screen>
 
-You can then upgrade NixOS to the latest version in the channel by
+To switch to a different NixOS channel, do
-running
 
 <screen>
-$ nix-channel --update nixos
+$ nix-channel --add http://nixos.org/channels/<replaceable>channel-name</replaceable> nixos
 </screen>
 
-and running the <command>nixos-rebuild</command> command as described
+(Be sure to include the <literal>nixos</literal> parameter at the
-in <xref linkend="sec-changing-config"/>.</para>
+end.)  For instance, to use the NixOS 13.10 stable channel:
+
+<screen>
+$ nix-channel --add http://nixos.org/channels/nixos-13.10 nixos
+</screen>
+
+But it you want to live on the bleeding edge:
+
+<screen>
+$ nix-channel --add http://nixos.org/channels/nixos-unstable nixos
+</screen>
+
+</para>
+
+<para>You can then upgrade NixOS to the latest version in your chosen
+channel by running
+
+<screen>
+$ nixos-rebuild switch --upgrade
+</screen>
+
+which is equivalent to the more verbose <literal>nix-channel --update
+nixos; nixos-rebuild switch</literal>.</para>
+
+<warning><para>It is generally safe to switch back and forth between
+channels.  The only exception is that a newer NixOS may also have a
+newer Nix version, which may involve an upgrade of Nix’s database
+schema.  This cannot be undone easily, so in that case you will not be
+able to go back to your original channel.</para></warning>
 
 </section>
 

nixos/doc/manual/options-to-docbook.xsl

@@ -36,23 +36,15 @@
                                select="attr[@name = 'description']/string/@value" />
                </para>
 
-               <para>
+               <xsl:if test="attr[@name = 'default']">
-                 <emphasis>Default:</emphasis>
+                 <para>
-                 <xsl:text> </xsl:text>
+                   <emphasis>Default:</emphasis>
-                 <xsl:choose>
+                   <xsl:text> </xsl:text>
-                   <xsl:when test="attr[@name = 'default']">
+                   <xsl:apply-templates select="attr[@name = 'default']" mode="top" />
-                     <literal>
+                 </para>
-                       <xsl:apply-templates select="attr[@name = 'default']" />
+               </xsl:if>
-                     </literal>
-                   </xsl:when>
-                   <xsl:otherwise>
-                     none
-                   </xsl:otherwise>
-                 </xsl:choose>
-               </para>
 
                <xsl:if test="attr[@name = 'example']">
-
                  <para>
                    <emphasis>Example:</emphasis>
                    <xsl:text> </xsl:text>
@@ -61,9 +53,7 @@
                        <programlisting><xsl:value-of select="attr[@name = 'example']/attrs/attr[@name = 'text']/string/@value" /></programlisting>
                      </xsl:when>
                      <xsl:otherwise>
-                       <literal>
+                       <xsl:apply-templates select="attr[@name = 'example']" mode="top" />
-                         <xsl:apply-templates select="attr[@name = 'example']" />
-                       </literal>
                      </xsl:otherwise>
                    </xsl:choose>
                  </para>
@@ -94,9 +84,34 @@
   </xsl:template>
 
 
+  <xsl:template match="*" mode="top">
+    <xsl:choose>
+      <xsl:when test="string[contains(@value, '&#010;')]">
+<programlisting>
+<xsl:text>''
+</xsl:text><xsl:value-of select='str:replace(string/@value, "${", "&apos;&apos;${")' /><xsl:text>''</xsl:text></programlisting>
+      </xsl:when>
+      <xsl:otherwise>
+        <literal><xsl:apply-templates /></literal>
+      </xsl:otherwise>
+    </xsl:choose>
+  </xsl:template>
+
+
+  <xsl:template match="null">
+    <xsl:text>null</xsl:text>
+  </xsl:template>
+
+
   <xsl:template match="string">
-    <!-- !!! escaping -->
+    <xsl:choose>
-    <xsl:text>"</xsl:text><xsl:value-of select="str:replace(str:replace(str:replace(@value, '\', '\\'), '&quot;', '\&quot;'), '&#010;', '\n')" /><xsl:text>"</xsl:text>
+      <xsl:when test="(contains(@value, '&quot;') or contains(@value, '\')) and not(contains(@value, '&#010;'))">
+        <xsl:text>''</xsl:text><xsl:value-of select='str:replace(@value, "${", "&apos;&apos;${")' /><xsl:text>''</xsl:text>
+      </xsl:when>
+      <xsl:otherwise>
+        <xsl:text>"</xsl:text><xsl:value-of select="str:replace(str:replace(str:replace(str:replace(@value, '\', '\\'), '&quot;', '\&quot;'), '&#010;', '\n'), '$', '\$')" /><xsl:text>"</xsl:text>
+      </xsl:otherwise>
+    </xsl:choose>
   </xsl:template>
 
 
@@ -142,14 +157,7 @@
 
 
   <xsl:template match="derivation">
-    <xsl:choose>
+    <replaceable>(build of <xsl:value-of select="attr[@name = 'name']/string/@value" />)</replaceable>
-      <xsl:when test="attr[@name = 'url']/string/@value">
-        <replaceable>(download of <xsl:value-of select="attr[@name = 'url']/string/@value" />)</replaceable>
-      </xsl:when>
-      <xsl:otherwise>
-        <replaceable>(build of <xsl:value-of select="attr[@name = 'name']/string/@value" />)</replaceable>
-      </xsl:otherwise>
-    </xsl:choose>
   </xsl:template>
 
   <xsl:template match="attr[@name = 'declarations' or @name = 'definitions']">

nixos/lib/eval-config.nix

@@ -7,23 +7,20 @@
 , baseModules ? import ../modules/module-list.nix
 , extraArgs ? {}
 , modules
+, check ? true
 }:
 
 let extraArgs_ = extraArgs; pkgs_ = pkgs; system_ = system; in
 
 rec {
 
-  # These are the NixOS modules that constitute the system configuration.
-  configComponents = modules ++ baseModules;
-
   # Merge the option definitions in all modules, forming the full
-  # system configuration.  It's not checked for undeclared options.
+  # system configuration.
-  systemModule =
+  inherit (pkgs.lib.evalModules {
-    pkgs.lib.fixMergeModules configComponents extraArgs;
+    modules = modules ++ baseModules;
-
+    args = extraArgs;
-  optionDefinitions = systemModule.config;
+    check = check && options.environment.checkConfigurationOptions.value;
-  optionDeclarations = systemModule.options;
+  }) config options;
-  inherit (systemModule) options;
 
   # These are the extra arguments passed to every module.  In
   # particular, Nixpkgs is passed through the "pkgs" argument.
@@ -56,16 +53,12 @@ rec {
           # define nixpkgs.config, so it's pointless to evaluate them.
           baseModules = [ ../modules/misc/nixpkgs.nix ];
           pkgs = import ./nixpkgs.nix { system = system_; config = {}; };
-        }).optionDefinitions.nixpkgs;
+          check = false;
+        }).config.nixpkgs;
       in
       {
         inherit system;
         inherit (nixpkgsOptions) config;
       });
 
-  # Optionally check wether all config values have corresponding
-  # option declarations.
-  config =
-    assert optionDefinitions.environment.checkConfigurationOptions -> pkgs.lib.checkModule "" systemModule;
-    systemModule.config;
 }

nixos/modules/config/fonts/fontconfig.nix

@@ -9,6 +9,7 @@ with pkgs.lib;
     fonts = {
 
       enableFontConfig = mkOption { # !!! should be enableFontconfig
+        type = types.bool;
         default = true;
         description = ''
           If enabled, a Fontconfig configuration file will be built

nixos/modules/config/gnu.nix

@@ -5,6 +5,7 @@ with pkgs.lib;
 {
   options = {
     gnu = mkOption {
+      type = types.bool;
       default = false;
       description =
         '' When enabled, GNU software is chosen by default whenever a there is

nixos/modules/config/i18n.nix

@@ -18,16 +18,18 @@ in
 
     i18n = {
       defaultLocale = mkOption {
+        type = types.str;
         default = "en_US.UTF-8";
         example = "nl_NL.UTF-8";
-        description = "
+        description = ''
           The default locale.  It determines the language for program
           messages, the format for dates and times, sort order, and so on.
           It also determines the character set, such as UTF-8.
-        ";
+        '';
       };
 
       supportedLocales = mkOption {
+        type = types.listOf types.str;
         default = ["all"];
         example = ["en_US.UTF-8/UTF-8" "nl_NL.UTF-8/UTF-8" "nl_NL/ISO-8859-1"];
         description = ''
@@ -40,22 +42,23 @@ in
       };
 
       consoleFont = mkOption {
+        type = types.str;
         default = "lat9w-16";
         example = "LatArCyrHeb-16";
-        description = "
+        description = ''
           The font used for the virtual consoles.  Leave empty to use
           whatever the <command>setfont</command> program considers the
           default font.
-        ";
+        '';
       };
 
       consoleKeyMap = mkOption {
+        type = types.str;
         default = "us";
         example = "fr";
-        description = "
+        description = ''
           The keyboard mapping table for the virtual consoles.
-        ";
+        '';
-        type = types.uniq types.string;
       };
 
     };

nixos/modules/config/networking.nix

@@ -15,6 +15,7 @@ in
   options = {
 
     networking.extraHosts = pkgs.lib.mkOption {
+      type = types.lines;
       default = "";
       example = "192.168.0.1 lanlocalhost";
       description = ''
@@ -23,6 +24,7 @@ in
     };
 
     networking.dnsSingleRequest = pkgs.lib.mkOption {
+      type = types.bool;
       default = false;
       description = ''
         Recent versions of glibc will issue both ipv4 (A) and ipv6 (AAAA)

nixos/modules/config/no-x-libs.nix

@@ -1,10 +1,12 @@
 { config, pkgs, ... }:
 
+with pkgs.lib;
+
 {
   options = {
-    environment.noXlibs = pkgs.lib.mkOption {
+    environment.noXlibs = mkOption {
+      type = types.bool;
       default = false;
-      example = true;
       description = ''
         Switch off the options in the default configuration that require X libraries.
         Currently this includes: ssh X11 forwarding, dbus, fonts.enableCoreFonts,
@@ -13,7 +15,7 @@
     };
   };
 
-  config = pkgs.lib.mkIf config.environment.noXlibs {
+  config = mkIf config.environment.noXlibs {
     programs.ssh.setXAuthLocation = false;
     fonts = {
       enableCoreFonts = false;

nixos/modules/config/nsswitch.nix

@@ -16,6 +16,7 @@ in
 
     # NSS modules.  Hacky!
     system.nssModules = mkOption {
+      type = types.listOf types.path;
       internal = true;
       default = [];
       description = ''
@@ -23,7 +24,6 @@ in
         several DNS resolution methods to be specified via
         <filename>/etc/nsswitch.conf</filename>.
       '';
-      merge = mergeListOption;
       apply = list:
         {
           inherit list;

nixos/modules/config/power-management.nix

@@ -17,6 +17,7 @@ in
     powerManagement = {
 
       enable = mkOption {
+        type = types.bool;
         default = true;
         description =
           ''
@@ -26,11 +27,13 @@ in
       };
 
       resumeCommands = mkOption {
+        type = types.lines;
         default = "";
         description = "Commands executed after the system resumes from suspend-to-RAM.";
       };
 
       powerUpCommands = mkOption {
+        type = types.lines;
         default = "";
         example = "${pkgs.hdparm}/sbin/hdparm -B 255 /dev/sda";
         description =
@@ -42,6 +45,7 @@ in
       };
 
       powerDownCommands = mkOption {
+        type = types.lines;
         default = "";
         example = "${pkgs.hdparm}/sbin/hdparm -B 255 /dev/sda";
         description =

nixos/modules/config/pulseaudio.nix

@@ -46,6 +46,7 @@ in {
 
     hardware.pulseaudio = {
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to enable the PulseAudio sound server.
@@ -72,12 +73,13 @@ in {
           The path to the configuration the PulseAudio server
           should use. By default, the "default.pa" configuration
           from the PulseAudio distribution is used.
-        ''; 
+        '';
       };
-  
+
       package = mkOption {
+        type = types.path;
         default = pulseaudio;
-        example = "pulseaudio.override { jackaudioSupport = true; }";
+        example = literalExample "pulseaudio.override { jackaudioSupport = true; }";
         description = ''
           The PulseAudio derivation to use.  This can be used to enable
           features (such as JACK support) that are not enabled in the
@@ -125,9 +127,9 @@ in {
         description = "PulseAudio system service user";
         home = pulseRuntimePath;
       };
-  
+
       users.extraGroups.pulse.gid = gid;
-  
+
       systemd.services.pulseaudio = {
         description = "PulseAudio system-wide server";
         wantedBy = [ "sound.target" ];

nixos/modules/config/shells-environment.nix

@@ -25,12 +25,17 @@ in
       '';
       type = types.attrsOf (mkOptionType {
         name = "a string or a list of strings";
-        merge = xs:
+        merge = loc: defs:
-          let xs' = evalProperties xs; in
+          let
-          if isList (head xs') then concatLists xs'
+            defs' = filterOverrides defs;
-          else if builtins.lessThan 1 (length xs') then abort "variable in ‘environment.variables’ has multiple values"
+            res = (head defs').value;
-          else if !builtins.isString (head xs') then abort "variable in ‘environment.variables’ does not have a string value"
+          in
-          else head xs';
+          if isList res then concatLists (getValues defs')
+          else if builtins.lessThan 1 (length defs') then
+            throw "The option `${showOption loc}' is defined multiple times, in ${showFiles (getFiles defs)}."
+          else if !builtins.isString res then
+            throw "The option `${showOption loc}' does not have a string value, in ${showFiles (getFiles defs)}."
+          else res;
       });
       apply = mapAttrs (n: v: if isList v then concatStringsSep ":" v else v);
     };

nixos/modules/config/swap.nix

@@ -34,13 +34,13 @@ with utils;
 
           device = mkOption {
             example = "/dev/sda3";
-            type = types.uniq types.string;
+            type = types.str;
             description = "Path of the device.";
           };
 
           label = mkOption {
             example = "swap";
-            type = types.uniq types.string;
+            type = types.str;
             description = ''
               Label of the device.  Can be used instead of <varname>device</varname>.
             '';
@@ -72,11 +72,8 @@ with utils;
         };
 
         config = {
-          device =
+          device = mkIf options.label.isDefined
-            if options.label.isDefined then
+            "/dev/disk/by-label/${config.label}";
-              "/dev/disk/by-label/${config.label}"
-            else
-              mkNotdef;
         };
 
       };

nixos/modules/config/sysctl.nix

@@ -7,7 +7,7 @@ let
   sysctlOption = mkOptionType {
     name = "sysctl option value";
     check = x: builtins.isBool x || builtins.isString x || builtins.isInt x;
-    merge = xs: last xs; # FIXME: hacky way to allow overriding in configuration.nix.
+    merge = args: defs: (last defs).value; # FIXME: hacky way to allow overriding in configuration.nix.
   };
 
 in

nixos/modules/config/system-path.nix

@@ -14,7 +14,7 @@ let
     '';
 
   requiredPackages =
-    [ config.environment.nix
+    [ config.nix.package
       pkgs.acl
       pkgs.attr
       pkgs.bashInteractive # bash with ncurses support
@@ -60,6 +60,7 @@ in
     environment = {
 
       systemPackages = mkOption {
+        type = types.listOf types.path;
         default = [];
         example = "[ pkgs.icecat3 pkgs.thunderbird ]";
         description = ''
@@ -74,6 +75,7 @@ in
       };
 
       pathsToLink = mkOption {
+        type = types.listOf types.str;
         # Note: We need `/lib' to be among `pathsToLink' for NSS modules
         # to work.
         default = [];
@@ -122,7 +124,7 @@ in
       postBuild =
         ''
           if [ -x $out/bin/update-mime-database -a -w $out/share/mime/packages ]; then
-              $out/bin/update-mime-database -V $out/share/mime
+              XDG_DATA_DIRS=$out/share $out/bin/update-mime-database -V $out/share/mime > /dev/null
           fi
 
           if [ -x $out/bin/gtk-update-icon-cache -a -f $out/share/icons/hicolor/index.theme ]; then

nixos/modules/config/timezone.nix

@@ -9,7 +9,7 @@ with pkgs.lib;
 
       timeZone = mkOption {
         default = "CET";
-        type = with types; uniq string;
+        type = types.str;
         example = "America/New_York";
         description = "The time zone used when displaying times and dates.";
       };

nixos/modules/config/users-groups.nix

@@ -12,14 +12,19 @@ let
     options = {
 
       name = mkOption {
-        type = with types; uniq string;
+        type = types.str;
         description = "The name of the user account. If undefined, the name of the attribute set will be used.";
       };
 
       description = mkOption {
-        type = with types; uniq string;
+        type = types.str;
         default = "";
-        description = "A short description of the user account.";
+        example = "Alice Q. User";
+        description = ''
+          A short description of the user account, typically the
+          user's full name.  This is actually the “GECOS” or “comment”
+          field in <filename>/etc/passwd</filename>.
+        '';
       };
 
       uid = mkOption {
@@ -29,25 +34,25 @@ let
       };
 
       group = mkOption {
-        type = with types; uniq string;
+        type = types.str;
         default = "nogroup";
         description = "The user's primary group.";
       };
 
       extraGroups = mkOption {
-        type = types.listOf types.string;
+        type = types.listOf types.str;
         default = [];
         description = "The user's auxiliary groups.";
       };
 
       home = mkOption {
-        type = with types; uniq string;
+        type = types.str;
         default = "/var/empty";
         description = "The user's home directory.";
       };
 
       shell = mkOption {
-        type = with types; uniq string;
+        type = types.str;
         default = "/run/current-system/sw/sbin/nologin";
         description = "The path to the user's shell.";
       };
@@ -65,9 +70,15 @@ let
       };
 
       password = mkOption {
-        type = with types; uniq (nullOr string);
+        type = with types; uniq (nullOr str);
         default = null;
-        description = "The user's password. If undefined, no password is set for the user.  Warning: do not set confidential information here because this data would be readable by all.  This option should only be used for public account such as guest.";
+        description = ''
+          The user's password. If undefined, no password is set for
+          the user.  Warning: do not set confidential information here
+          because it is world-readable in the Nix store.  This option
+          should only be used for public accounts such as
+          <literal>guest</literal>.
+        '';
       };
 
       isSystemUser = mkOption {
@@ -79,11 +90,11 @@ let
       createUser = mkOption {
         type = types.bool;
         default = true;
-        description = "
+        description = ''
           Indicates if the user should be created automatically as a local user.
           Set this to false if the user for instance is an LDAP user. NixOS will
           then not modify any of the basic properties for the user account.
-        ";
+        '';
       };
 
       isAlias = mkOption {
@@ -107,7 +118,7 @@ let
     options = {
 
       name = mkOption {
-        type = with types; uniq string;
+        type = types.str;
         description = "The name of the group. If undefined, the name of the attribute set will be used.";
       };
 
@@ -149,13 +160,12 @@ in
       example = {
         alice = {
           uid = 1234;
-          description = "Alice";
+          description = "Alice Q. User";
           home = "/home/alice";
           createHome = true;
           group = "users";
           extraGroups = ["wheel"];
           shell = "/bin/sh";
-          password = "foobar";
         };
       };
       description = ''

nixos/modules/hardware/all-firmware.nix

@@ -1,4 +1,6 @@
-{pkgs, config, ...}:
+{ config, pkgs, ... }:
+
+with pkgs.lib;
 
 {
 
@@ -6,9 +8,9 @@
 
   options = {
 
-    hardware.enableAllFirmware = pkgs.lib.mkOption {
+    hardware.enableAllFirmware = mkOption {
       default = false;
-      type = pkgs.lib.types.bool;
+      type = types.bool;
       description = ''
         Turn on this option if you want to enable all the firmware shipped with Debian/Ubuntu.
       '';
@@ -19,7 +21,7 @@
 
   ###### implementation
 
-  config = pkgs.lib.mkIf config.hardware.enableAllFirmware {
+  config = mkIf config.hardware.enableAllFirmware {
     hardware.firmware = [ "${pkgs.firmwareLinuxNonfree}/lib/firmware" ];
   };
 

nixos/modules/hardware/pcmcia.nix

@@ -18,16 +18,16 @@ in
 
     hardware.pcmcia = {
       enable = mkOption {
+        type = types.bool;
         default = false;
-        merge = mergeEnableOption;
         description = ''
           Enable this option to support PCMCIA card.
         '';
       };
 
       firmware = mkOption {
+        type = types.listOf types.path;
         default = [];
-        merge = mergeListOption;
         description = ''
           List of firmware used to handle specific PCMCIA card.
         '';
@@ -36,7 +36,7 @@ in
       config = mkOption {
         default = null;
         description = ''
-          Path to the configuration file which map the memory, irq
+          Path to the configuration file which maps the memory, IRQs
           and ports used by the PCMCIA hardware.
         '';
       };

nixos/modules/installer/cd-dvd/channel.nix

@@ -33,7 +33,7 @@ in
       if ! [ -e /var/lib/nixos/did-channel-init ]; then
         echo "unpacking the NixOS/Nixpkgs sources..."
         mkdir -p /nix/var/nix/profiles/per-user/root
-        ${config.environment.nix}/bin/nix-env -p /nix/var/nix/profiles/per-user/root/channels \
+        ${config.nix.package}/bin/nix-env -p /nix/var/nix/profiles/per-user/root/channels \
           -i ${channelSources} --quiet --option use-substitutes false
         mkdir -m 0700 -p /root/.nix-defexpr
         ln -s /nix/var/nix/profiles/per-user/root/channels /root/.nix-defexpr/channels

nixos/modules/installer/cd-dvd/iso-image.nix

@@ -298,12 +298,12 @@ in
       ''
         # After booting, register the contents of the Nix store on the
         # CD in the Nix database in the tmpfs.
-        ${config.environment.nix}/bin/nix-store --load-db < /nix/store/nix-path-registration
+        ${config.nix.package}/bin/nix-store --load-db < /nix/store/nix-path-registration
 
         # nixos-rebuild also requires a "system" profile and an
         # /etc/NIXOS tag.
         touch /etc/NIXOS
-        ${config.environment.nix}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system
+        ${config.nix.package}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system
       '';
 
     # Add vfat support to the initrd to enable people to copy the

nixos/modules/installer/cd-dvd/live-dvd.nix

@@ -1,78 +0,0 @@
-{ config, pkgs, ... }:
-
-{
-  imports = [ ./installation-cd-base.nix ];
-
-  # Build the build-time dependencies of this configuration on the DVD
-  # to speed up installation.
-  isoImage.storeContents = [ config.system.build.toplevel.drvPath ];
-
-  # Include lots of packages.
-  environment.systemPackages =
-    [ pkgs.utillinuxCurses
-      pkgs.upstartJobControl
-      pkgs.iproute
-      pkgs.bc
-      pkgs.fuse
-      pkgs.zsh
-      pkgs.sqlite
-      pkgs.gnupg
-      pkgs.manpages
-      pkgs.pinentry
-      pkgs.screen
-      pkgs.patch
-      pkgs.which
-      pkgs.diffutils
-      pkgs.file
-      pkgs.irssi
-      pkgs.mcabber
-      pkgs.mutt
-      pkgs.emacs
-      pkgs.vimHugeX
-      pkgs.bvi
-      pkgs.ddrescue
-      pkgs.cdrkit
-      pkgs.btrfsProgs
-      pkgs.xfsprogs
-      pkgs.jfsutils
-      pkgs.jfsrec
-      pkgs.ntfs3g
-      pkgs.subversion16
-      pkgs.monotone
-      pkgs.git
-      pkgs.darcs
-      pkgs.mercurial
-      pkgs.bazaar
-      pkgs.cvs
-      pkgs.pciutils
-      pkgs.hddtemp
-      pkgs.sdparm
-      pkgs.hdparm
-      pkgs.usbutils
-      pkgs.openssh
-      pkgs.lftp
-      pkgs.w3m
-      pkgs.openssl
-      pkgs.ncat
-      pkgs.lynx
-      pkgs.wget
-      pkgs.elinks
-      pkgs.socat
-      pkgs.squid
-      pkgs.unrar
-      pkgs.zip
-      pkgs.unzip
-      pkgs.lzma
-      pkgs.cabextract
-      pkgs.cpio
-      pkgs.lsof
-      pkgs.ltrace
-      pkgs.perl
-      pkgs.python
-      pkgs.ruby
-      pkgs.guile
-      pkgs.clisp
-      pkgs.tcl
-    ];
-
-}

nixos/modules/installer/cd-dvd/system-tarball-fuloong2f.nix

@@ -152,7 +152,7 @@ in
   # default root password is empty.
   services.openssh.enable = true;
 
-  jobs.openssh.startOn = pkgs.lib.mkOverrideTemplate 50 {} "";
+  jobs.openssh.startOn = pkgs.lib.mkOverride 50 "";
 
   boot.loader.grub.enable = false;
   boot.loader.generationsDir.enable = false;

nixos/modules/installer/cd-dvd/system-tarball-pc.nix

@@ -109,7 +109,7 @@ in
   # not be started by default on the installation CD because the
   # default root password is empty.
   services.openssh.enable = true;
-  jobs.openssh.startOn = pkgs.lib.mkOverrideTemplate 50 {} "";
+  jobs.openssh.startOn = pkgs.lib.mkOverride 50 "";
 
   # To be able to use the systemTarball to catch troubles.
   boot.crashDump = {

nixos/modules/installer/cd-dvd/system-tarball-sheevaplug.nix

@@ -165,7 +165,7 @@ in
   # not be started by default on the installation CD because the
   # default root password is empty.
   services.openssh.enable = true;
-  jobs.openssh.startOn = pkgs.lib.mkOverrideTemplate 50 {} "";
+  jobs.openssh.startOn = pkgs.lib.mkOverride 50 "";
 
   # cpufrequtils fails to build on non-pc
   powerManagement.enable = false;

nixos/modules/installer/cd-dvd/system-tarball.nix

@@ -77,14 +77,14 @@ in
         # After booting, register the contents of the Nix store on the
         # CD in the Nix database in the tmpfs.
         if [ -f /nix-path-registration ]; then
-          ${config.environment.nix}/bin/nix-store --load-db < /nix-path-registration &&
+          ${config.nix.package}/bin/nix-store --load-db < /nix-path-registration &&
           rm /nix-path-registration
         fi
 
         # nixos-rebuild also requires a "system" profile and an
         # /etc/NIXOS tag.
         touch /etc/NIXOS
-        ${config.environment.nix}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system
+        ${config.nix.package}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system
       '';
 
   };

nixos/modules/installer/tools/nixos-option.sh

@@ -1,5 +1,7 @@
 #! @shell@ -e
 
+# FIXME: rewrite this in a more suitable language.
+
 usage () {
     exec man nixos-option
     exit 1
@@ -90,24 +92,25 @@ evalNix(){
 }
 
 evalAttr(){
-  local prefix=$1
+  local prefix="$1"
-  local suffix=$2
+  local strict="$2"
-  local strict=$3
+  local suffix="$3"
   echo "(import <nixos> {}).$prefix${option:+.$option}${suffix:+.$suffix}" |
     evalNix ${strict:+--strict}
 }
 
 evalOpt(){
-  evalAttr "eval.options" "$@"
+  evalAttr "options" "" "$@"
 }
 
 evalCfg(){
-  evalAttr "config" "$@"
+  local strict="$1"
+  evalAttr "config" "$strict"
 }
 
 findSources(){
   local suffix=$1
-  echo "builtins.map (f: f.source) (import <nixos> {}).eval.options${option:+.$option}.$suffix" |
+  echo "(import <nixos> {}).options${option:+.$option}.$suffix" |
     evalNix --strict
 }
 
@@ -143,7 +146,7 @@ let
   nixos = import <nixos> {};
   nixpkgs = import <nixpkgs> {};
   sources = builtins.map (f: f.source);
-  opt = reach nixos.eval.options;
+  opt = reach nixos.options;
   cfg = reach nixos.config;
 in
 
@@ -186,7 +189,7 @@ EOF
 fi
 
 if test "$(evalOpt "_type" 2> /dev/null)" = '"option"'; then
-  $value && evalCfg;
+  $value && evalCfg 1
 
   if $desc; then
     $value && echo;
@@ -212,14 +215,14 @@ if test "$(evalOpt "_type" 2> /dev/null)" = '"option"'; then
     nixMap printPath "$(findSources "declarations")"
     echo ""
     echo "Defined by:"
-    nixMap printPath "$(findSources "definitions")"
+    nixMap printPath "$(findSources "files")"
     echo ""
   fi
 
 else
   # echo 1>&2 "Warning: This value is not an option."
 
-  result=$(evalCfg)
+  result=$(evalCfg "")
   if names=$(attrNames "$result" 2> /dev/null); then
     echo 1>&2 "This attribute set contains:"
     escapeQuotes () { eval echo "$1"; }

nixos/modules/installer/tools/nixos-rebuild.sh

@@ -109,7 +109,7 @@ fi
 # more conservative.
 if [ "$action" != dry-run -a -n "$buildNix" ]; then
     echo "building Nix..." >&2
-    if ! nix-build '<nixpkgs/nixos>' -A config.environment.nix -o $tmpDir/nix "${extraBuildFlags[@]}" > /dev/null; then
+    if ! nix-build '<nixpkgs/nixos>' -A config.nix.package -o $tmpDir/nix "${extraBuildFlags[@]}" > /dev/null; then
         if ! nix-build '<nixpkgs/nixos>' -A nixFallback -o $tmpDir/nix "${extraBuildFlags[@]}" > /dev/null; then
             nix-build '<nixpkgs>' -A nixUnstable -o $tmpDir/nix "${extraBuildFlags[@]}" > /dev/null
         fi
@@ -121,7 +121,7 @@ fi
 # Update the version suffix if we're building from Git (so that
 # nixos-version shows something useful).
 if nixpkgs=$(nix-instantiate --find-file nixpkgs "${extraBuildFlags[@]}"); then
-    suffix=$(@shell@ $nixpkgs/nixos/modules/installer/tools/get-version-suffix "${extraBuildFlags[@]}")
+    suffix=$(@shell@ $nixpkgs/nixos/modules/installer/tools/get-version-suffix "${extraBuildFlags[@]}" || true)
     if [ -n "$suffix" ]; then
         echo -n "$suffix" > "$nixpkgs/.version-suffix" || true
     fi

nixos/modules/installer/tools/tools.nix

@@ -22,10 +22,10 @@ let
     src = ./nixos-install.sh;
 
     inherit (pkgs) perl pathsFromGraph;
-    nix = config.environment.nix;
+    nix = config.nix.package;
 
     nixClosure = pkgs.runCommand "closure"
-      { exportReferencesGraph = ["refs" config.environment.nix]; }
+      { exportReferencesGraph = ["refs" config.nix.package]; }
       "cp refs $out";
   };
 
@@ -52,6 +52,7 @@ let
     inherit (config.system) nixosVersion nixosCodeName;
   };
 
+  /*
   nixos-gui = pkgs.xulrunnerWrapper {
     launcher = "nixos-gui";
     application = pkgs.stdenv.mkDerivation {
@@ -71,10 +72,12 @@ let
       };
     };
   };
+  */
 
 in
 
 {
+  /*
   options = {
 
     installer.enableGraphicalTools = pkgs.lib.mkOption {
@@ -87,6 +90,7 @@ in
     };
 
   };
+  */
 
   config = {
     environment.systemPackages =
@@ -96,10 +100,10 @@ in
         nixos-generate-config
         nixos-option
         nixos-version
-      ] ++ pkgs.lib.optional cfg.enableGraphicalTools nixos-gui;
+      ];
 
     system.build = {
-      inherit nixos-install nixos-generate-config nixos-option;
+      inherit nixos-install nixos-generate-config nixos-option nixos-rebuild;
     };
   };
 }

nixos/modules/misc/assertions.nix

@@ -15,10 +15,10 @@ in
   options = {
 
     assertions = mkOption {
+      type = types.listOf types.unspecified;
       internal = true;
       default = [];
       example = [ { assertion = false; message = "you can't enable this for that reason"; } ];
-      merge = pkgs.lib.mergeListOption;
       description = ''
         This option allows modules to express conditions that must
         hold for the evaluation of the system configuration to

nixos/modules/misc/check-config.nix

@@ -1,10 +1,12 @@
-{pkgs, ...}:
+{ pkgs, ... }:
+
+with pkgs.lib;
 
 {
   options = {
-    environment.checkConfigurationOptions = pkgs.lib.mkOption {
+    environment.checkConfigurationOptions = mkOption {
+      type = types.bool;
       default = true;
-      example = false;
       description = ''
         Whether to check the validity of the entire configuration.
       '';

nixos/modules/misc/crashdump.nix

@@ -14,8 +14,8 @@ in
     boot = {
       crashDump = {
         enable = mkOption {
+          type = types.bool;
           default = false;
-          example = true;
           description = ''
             If enabled, NixOS will set up a kernel that will
             boot on crash, and leave the user to a stage1 debug1devices
@@ -35,6 +35,7 @@ in
           '';
         };
         kernelParams = mkOption {
+          type = types.listOf types.str;
           default = [ "debug1devices" ];
           description = ''
             Parameters that will be passed to the kernel kexec-ed on crash.

nixos/modules/misc/ids.nix

@@ -7,12 +7,14 @@
   options = {
 
     ids.uids = pkgs.lib.mkOption {
+      internal = true;
       description = ''
         The user IDs used in NixOS.
       '';
     };
 
     ids.gids = pkgs.lib.mkOption {
+      internal = true;
       description = ''
         The group IDs used in NixOS.
       '';
@@ -102,6 +104,8 @@
       tcpcryptd = 93; # tcpcryptd uses a hard-coded uid. We patch it in Nixpkgs to match this choice.
       zope2 = 94;
       firebird = 95;
+      redis = 96;
+      haproxy = 97;
 
       # When adding a uid, make sure it doesn't match an existing gid.
 
@@ -188,6 +192,7 @@
       quassel = 89;
       amule = 90;
       minidlna = 91;
+      haproxy = 92;
 
       # When adding a gid, make sure it doesn't match an existing uid.
 

nixos/modules/misc/locate.nix

@@ -17,8 +17,8 @@ in
     services.locate = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
-        example = true;
         description = ''
           If enabled, NixOS will periodically update the database of
           files used by the <command>locate</command> command.
@@ -26,11 +26,12 @@ in
       };
 
       period = mkOption {
+        type = types.str;
         default = "15 02 * * *";
         description = ''
           This option defines (in the format used by cron) when the
           locate database is updated.
-          The default is to update at 02:15 (at night) every day.
+          The default is to update at 02:15 at night every day.
         '';
       };
 

nixos/modules/misc/nixpkgs.nix

@@ -26,7 +26,7 @@ let
   configType = mkOptionType {
     name = "nixpkgs config";
     check = traceValIfNot isConfig;
-    merge = fold mergeConfig {};
+    merge = args: fold (def: mergeConfig def.value) {};
   };
 
 in
@@ -59,7 +59,7 @@ in
     };
 
     nixpkgs.system = mkOption {
-      default = pkgs.stdenv.system;
+      type = types.str;
       description = ''
         Specifies the Nix platform type for which NixOS should be built.
         If unset, it defaults to the platform type of your host system
@@ -70,4 +70,8 @@ in
     };
 
   };
+
+  config = {
+    nixpkgs.system = mkDefault pkgs.stdenv.system;
+  };
 }

nixos/modules/misc/passthru.nix

@@ -6,6 +6,7 @@
 {
   options = {
     passthru = pkgs.lib.mkOption {
+      visible = false;
       description = ''
         This attribute set will be exported as a system attribute.
         You can put whatever you want here.

nixos/modules/misc/version.nix

@@ -8,31 +8,31 @@ with pkgs.lib;
 
     system.nixosVersion = mkOption {
       internal = true;
-      type = types.uniq types.string;
+      type = types.str;
       description = "NixOS version.";
     };
 
     system.nixosVersionSuffix = mkOption {
       internal = true;
-      type = types.uniq types.string;
+      type = types.str;
       description = "NixOS version suffix.";
     };
 
     system.nixosRevision = mkOption {
       internal = true;
-      type = types.uniq types.string;
+      type = types.str;
       description = "NixOS Git revision hash.";
     };
 
     system.nixosCodeName = mkOption {
       internal = true;
-      type = types.uniq types.string;
+      type = types.str;
       description = "NixOS release code name.";
     };
 
     system.defaultChannel = mkOption {
       internal = true;
-      type = types.uniq types.string;
+      type = types.str;
       default = https://nixos.org/channels/nixos-unstable;
       description = "Default NixOS channel to which the root user is subscribed.";
     };
@@ -58,18 +58,15 @@ with pkgs.lib;
     # Generate /etc/os-release.  See
     # http://0pointer.de/public/systemd-man/os-release.html for the
     # format.
-    environment.etc = singleton
+    environment.etc."os-release".text =
-      { source = pkgs.writeText "os-release"
+      ''
-          ''
+        NAME=NixOS
-            NAME=NixOS
+        ID=nixos
-            ID=nixos
+        VERSION="${config.system.nixosVersion} (${config.system.nixosCodeName})"
-            VERSION="${config.system.nixosVersion} (${config.system.nixosCodeName})"
+        VERSION_ID="${config.system.nixosVersion}"
-            VERSION_ID="${config.system.nixosVersion}"
+        PRETTY_NAME="NixOS ${config.system.nixosVersion} (${config.system.nixosCodeName})"
-            PRETTY_NAME="NixOS ${config.system.nixosVersion} (${config.system.nixosCodeName})"
+        HOME_URL="http://nixos.org/"
-            HOME_URL="http://nixos.org/"
+      '';
-          '';
-        target = "os-release";
-      };
 
   };
 

nixos/modules/module-list.nix

@@ -150,12 +150,12 @@
   ./services/networking/cntlm.nix
   ./services/networking/chrony.nix
   ./services/networking/ddclient.nix
-  #./services/networking/dhclient.nix
   ./services/networking/dhcpcd.nix
   ./services/networking/dhcpd.nix
   ./services/networking/dnsmasq.nix
   ./services/networking/ejabberd.nix
   ./services/networking/firewall.nix
+  ./services/networking/haproxy.nix
   ./services/networking/tcpcrypt.nix
   ./services/networking/flashpolicyd.nix
   ./services/networking/freenet.nix
@@ -276,7 +276,7 @@
   ./tasks/scsi-link-power-management.nix
   ./tasks/swraid.nix
   ./virtualisation/libvirtd.nix
-  ./virtualisation/nova.nix
+  #./virtualisation/nova.nix
   ./virtualisation/virtualbox-guest.nix
   ./virtualisation/xen-dom0.nix
 ]

nixos/modules/profiles/clone-config.nix

@@ -16,7 +16,8 @@ let
   # cannot serialized attribute set given in the list of modules (that's why
   # you should use files).
   moduleFiles =
-    filter isPath modules;
+    # FIXME: use typeOf (Nix 1.6.1).
+    filter (x: !isAttrs x && !builtins.isFunction x) modules;
 
   # Partition module files because between NixOS and non-NixOS files.  NixOS
   # files may change if the repository is updated.

nixos/modules/programs/shadow.nix

@@ -48,7 +48,7 @@ in
         Rather, it should be the path of a symlink that points to the
         actual shell in the Nix store.
       '';
-      type = types.uniq types.path;
+      type = types.path;
     };
 
   };

nixos/modules/programs/ssh.nix

@@ -16,6 +16,7 @@ in
     programs.ssh = {
 
       forwardX11 = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to request X11 forwarding on outgoing connections by default.
@@ -29,18 +30,21 @@ in
       };
 
       setXAuthLocation = mkOption {
+        type = types.bool;
         default = true;
         description = ''
           Whether to set the path to <command>xauth</command> for X11-forwarded connections.
-          Pulls in X11 dependency.
+          This causes a dependency on X11 packages.
         '';
       };
 
       extraConfig = mkOption {
+        type = types.lines;
         default = "";
         description = ''
           Extra configuration text appended to <filename>ssh_config</filename>.
-          See the ssh_config(5) man page for help.
+          See <citerefentry><refentrytitle>ssh_config</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+          for help.
         '';
       };
     };

nixos/modules/rename.nix

@@ -32,7 +32,6 @@ let
     zipAttrsWith (n: v:
       if tail v != [] then
         if n == "_type" then (head v)
-        else if n == "extraConfigs" then concatLists v
         else if n == "warnings" then concatLists v
         else if n == "description" || n == "apply" then
           abort "Cannot rename an option to multiple options."
@@ -55,12 +54,7 @@ let
             inherit visible;
           });
         }
-        { options = setTo (mkOption {
+        { config = setTo (mkIf (fromOf options).isDefined (define (mkMerge (fromOf options).definitions)));
-            extraConfigs =
-              let externalDefs = (fromOf options).definitions; in
-              if externalDefs == [] then []
-              else map (def: def.value) (define externalDefs);
-          });
         }
       ];
 
@@ -75,10 +69,9 @@ let
 
 in zipModules ([]
 
-# usage example:
+++ obsolete [ "environment" "x11Packages" ] [ "environment" "systemPackages" ]
-# ++ alias [ "services" "xserver" "slim" "theme" ] [ "services" "xserver" "displayManager" "slim" "theme" ]
-++ obsolete [ "environment" "extraPackages" ] [ "environment" "systemPackages" ]
 ++ obsolete [ "environment" "enableBashCompletion" ] [ "programs" "bash" "enableCompletion" ]
+++ obsolete [ "environment" "nix" ] [ "nix" "package" ]
 
 ++ obsolete [ "security" "extraSetuidPrograms" ] [ "security" "setuidPrograms" ]
 ++ obsolete [ "networking" "enableWLAN" ] [ "networking" "wireless" "enable" ]
@@ -98,6 +91,7 @@ in zipModules ([]
 ++ obsolete [ "boot" "grubSplashImage" ] [ "boot" "loader" "grub" "splashImage" ]
 
 ++ obsolete [ "boot" "initrd" "extraKernelModules" ] [ "boot" "initrd" "kernelModules" ]
+++ obsolete [ "boot" "extraKernelParams" ] [ "boot" "kernelParams" ]
 
 # OpenSSH
 ++ obsolete [ "services" "sshd" "ports" ] [ "services" "openssh" "ports" ]

nixos/modules/security/apparmor.nix

@@ -15,6 +15,7 @@ with pkgs.lib;
     security.apparmor = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Enable AppArmor application security system. Enable only if
@@ -23,8 +24,8 @@ with pkgs.lib;
       };
 
       profiles = mkOption {
+        type = types.listOf types.path;
         default = [];
-        merge = mergeListOption;
         description = ''
           List of file names of AppArmor profiles.
         '';

nixos/modules/security/pam.nix

@@ -13,7 +13,7 @@ let
 
       name = mkOption {
         example = "sshd";
-        type = types.uniq types.string;
+        type = types.str;
         description = "Name of the PAM service.";
       };
 
@@ -133,7 +133,7 @@ let
       };
 
       text = mkOption {
-        type = types.nullOr types.string;
+        type = types.nullOr types.lines;
         description = "Contents of the PAM service file.";
       };
 

nixos/modules/security/pam_usb.nix

@@ -17,6 +17,7 @@ in
 
     security.pam.usb = {
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Enable USB login for all login systems that support it.  For

nixos/modules/security/polkit.nix

@@ -13,11 +13,13 @@ in
   options = {
 
     security.polkit.enable = mkOption {
+      type = types.bool;
       default = true;
       description = "Whether to enable PolKit.";
     };
 
     security.polkit.permissions = mkOption {
+      type = types.lines;
       default = "";
       example =
         ''
@@ -49,6 +51,7 @@ in
     };
 
     security.polkit.adminIdentities = mkOption {
+      type = types.str;
       default = "unix-user:0;unix-group:wheel";
       example = "";
       description =

nixos/modules/security/rngd.nix

@@ -5,6 +5,7 @@ with pkgs.lib;
 {
   options = {
     security.rngd.enable = mkOption {
+      type = types.bool;
       default = true;
       description = ''
         Whether to enable the rng daemon, which adds entropy from

nixos/modules/security/rtkit.nix

@@ -10,6 +10,7 @@ with pkgs.lib;
   options = {
 
     security.rtkit.enable = mkOption {
+      type = types.bool;
       default = false;
       description = ''
         Whether to enable the RealtimeKit system service, which hands

nixos/modules/security/setuid-wrappers.nix

@@ -25,7 +25,9 @@ in
   options = {
 
     security.setuidPrograms = mkOption {
+      type = types.listOf types.str;
       default = [];
+      example = ["passwd"];
       description = ''
         The Nix store cannot contain setuid/setgid programs directly.
         For this reason, NixOS can automatically generate wrapper
@@ -36,6 +38,7 @@ in
     };
 
     security.setuidOwners = mkOption {
+      type = types.listOf types.attrs;
       default = [];
       example =
         [ { program = "sendmail";
@@ -53,6 +56,8 @@ in
     };
 
     security.wrapperDir = mkOption {
+      internal = true;
+      type = types.path;
       default = "/var/setuid-wrappers";
       description = ''
         This option defines the path to the setuid wrappers.  It

nixos/modules/security/sudo.nix

@@ -17,6 +17,7 @@ in
   options = {
 
     security.sudo.enable = mkOption {
+      type = types.bool;
       default = true;
       description =
         ''
@@ -26,6 +27,7 @@ in
     };
 
     security.sudo.wheelNeedsPassword = mkOption {
+      type = types.bool;
       default = true;
       description =
         ''
@@ -35,6 +37,7 @@ in
       };
 
     security.sudo.configFile = mkOption {
+      type = types.lines;
       # Note: if syntax errors are detected in this file, the NixOS
       # configuration will fail to build.
       description =

nixos/modules/services/audio/alsa.nix

@@ -20,14 +20,15 @@ in
     sound = {
 
       enable = mkOption {
+        type = types.bool;
         default = true;
         description = ''
           Whether to enable ALSA sound.
         '';
-        merge = mergeEnableOption;
       };
 
       enableOSSEmulation = mkOption {
+        type = types.bool;
         default = true;
         description = ''
           Whether to enable ALSA OSS emulation (with certain cards sound mixing may not work!).

nixos/modules/services/audio/fuppes.nix

@@ -21,7 +21,7 @@ with pkgs.lib;
 
       name = mkOption {
         example = "Media Center";
-        type = with types; uniq string;
+        type = types.str;
         description = ''
           Enables Fuppes (UPnP A/V Media Server).  Can be used to watch
           photos, video and listen to music from a phone/tv connected to the
@@ -41,7 +41,7 @@ with pkgs.lib;
 
         file = mkOption {
           default = "/var/log/fuppes.log";
-          type = with types; uniq string;
+          type = types.str;
           description = ''
             File which will contains the log produced by the daemon.
           '';
@@ -50,7 +50,7 @@ with pkgs.lib;
 
       config = mkOption {
         example = "/etc/fuppes/fuppes.cfg";
-        type = with types; uniq string;
+        type = types.str;
         description = ''
           Mutable configuration file which can be edited with the web
           interface.  Due to possible modification, double quote the full
@@ -69,7 +69,7 @@ with pkgs.lib;
 
       database = mkOption {
         default = "/var/lib/fuppes/fuppes.db";
-        type = with types; uniq string;
+        type = types.str;
         description = ''
           Database file which index all shared files.
         '';
@@ -88,7 +88,7 @@ with pkgs.lib;
       user = mkOption {
         default = "root"; # The default is not secure.
         example = "fuppes";
-        type = with types; uniq string;
+        type = types.str;
         description = ''
           Name of the user which own the configuration files and under which
           the fuppes daemon will be executed.

nixos/modules/services/databases/4store-endpoint.nix

@@ -24,12 +24,12 @@ with pkgs.lib;
       };
 
       listenAddress = mkOption {
-	default = null;
+        default = null;
         description = "IP address to listen on.";
       };
 
       port = mkOption {
-	default = 8080;
+        default = 8080;
         description = "port to listen on.";
       };
 
@@ -45,9 +45,12 @@ with pkgs.lib;
 
   ###### implementation
 
-  config = mkIf cfg.enable (
+  config = mkIf cfg.enable {
-    mkAssert (cfg.enable -> cfg.database != "")
+
-      "Must specify database name" {
+    assertions = singleton
+      { assertion = cfg.enable -> cfg.database != "";
+        message = "Must specify 4Store database name";
+      };
 
     users.extraUsers = singleton
       { name = endpointUser;
@@ -63,10 +66,10 @@ with pkgs.lib;
       startOn = "filesystem";
 
       exec = ''
-	${run} '${pkgs.rdf4store}/bin/4s-httpd -D ${cfg.options} ${if cfg.listenAddress!=null then "-H ${cfg.listenAddress}" else "" } -p ${toString cfg.port} ${cfg.database}'
+        ${run} '${pkgs.rdf4store}/bin/4s-httpd -D ${cfg.options} ${if cfg.listenAddress!=null then "-H ${cfg.listenAddress}" else "" } -p ${toString cfg.port} ${cfg.database}'
       '';
     };
 
-  });
+  };
 
 }

nixos/modules/services/databases/4store.nix

@@ -36,9 +36,12 @@ with pkgs.lib;
 
   ###### implementation
 
-  config = mkIf cfg.enable (
+  config = mkIf cfg.enable {
-    mkAssert (cfg.enable -> cfg.database != "")
+
-      "Must specify database name" {
+    assertions = singleton
+      { assertion = cfg.enable -> cfg.database != "";
+        message = "Must specify 4Store database name.";
+      };
 
     users.extraUsers = singleton
       { name = fourStoreUser;
@@ -56,16 +59,16 @@ with pkgs.lib;
       preStart = ''
         mkdir -p ${stateDir}/
         chown ${fourStoreUser} ${stateDir}
-	if ! test -e "${stateDir}/${cfg.database}"; then
+        if ! test -e "${stateDir}/${cfg.database}"; then
-	  ${run} -c '${pkgs.rdf4store}/bin/4s-backend-setup ${cfg.database}'
+          ${run} -c '${pkgs.rdf4store}/bin/4s-backend-setup ${cfg.database}'
         fi
       '';
 
       exec = ''
-	${run} -c '${pkgs.rdf4store}/bin/4s-backend -D ${cfg.options} ${cfg.database}'
+        ${run} -c '${pkgs.rdf4store}/bin/4s-backend -D ${cfg.options} ${cfg.database}'
       '';
     };
 
-  });
+  };
 
 }

nixos/modules/services/databases/postgresql.nix

@@ -46,6 +46,7 @@ in
     services.postgresql = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to run PostgreSQL.
@@ -53,6 +54,7 @@ in
       };
 
       package = mkOption {
+        type = types.path;
         example = literalExample "pkgs.postgresql92";
         description = ''
           PostgreSQL package to use.
@@ -60,6 +62,7 @@ in
       };
 
       port = mkOption {
+        type = types.int;
         default = "5432";
         description = ''
           Port for PostgreSQL.
@@ -67,6 +70,7 @@ in
       };
 
       dataDir = mkOption {
+        type = types.path;
         default = "/var/db/postgresql";
         description = ''
           Data directory for PostgreSQL.
@@ -74,6 +78,7 @@ in
       };
 
       authentication = mkOption {
+        type = types.lines;
         default = "";
         description = ''
           Defines how users authenticate themselves to the server.
@@ -81,6 +86,7 @@ in
       };
 
       identMap = mkOption {
+        type = types.lines;
         default = "";
         description = ''
           Defines the mapping from system users to database users.
@@ -88,14 +94,15 @@ in
       };
 
       initialScript = mkOption {
-        default = null;
         type = types.nullOr types.path;
+        default = null;
         description = ''
           A file containing SQL statements to execute on first startup.
         '';
       };
 
       enableTCPIP = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to run PostgreSQL with -i flag to enable TCP/IP connections.
@@ -103,8 +110,9 @@ in
       };
 
       extraPlugins = mkOption {
+        type = types.listOf types.path;
         default = [];
-        example = "pkgs.postgis"; # of course don't use a string here!
+        example = literalExample "pkgs.postgis";
         description = ''
           When this list contains elements a new store path is created.
           PostgreSQL and the elments are symlinked into it. Then pg_config,
@@ -118,15 +126,16 @@ in
       };
 
       extraConfig = mkOption {
+        type = types.lines;
         default = "";
         description = "Additional text to be appended to <filename>postgresql.conf</filename>.";
       };
 
       recoveryConfig = mkOption {
+        type = types.nullOr types.lines;
         default = null;
-        type = types.nullOr types.string;
         description = ''
-          Values to put into recovery.conf file.
+          Contents of the <filename>recovery.conf</filename> file.
         '';
       };
     };

nixos/modules/services/databases/redis.nix

@@ -14,6 +14,7 @@ let
     ${condOption "unixsocket" cfg.unixSocket}
     loglevel ${cfg.logLevel}
     logfile ${cfg.logfile}
+    syslog-enabled ${redisBool cfg.syslog}
     databases ${toString cfg.databases}
     ${concatMapStrings (d: "save ${toString (builtins.elemAt d 0)} ${toString (builtins.elemAt d 1)}\n") cfg.save}
     dbfilename ${cfg.dbFilename}
@@ -82,12 +83,18 @@ in
       };
 
       logfile = mkOption {
-        default = "stdout";
+        default = "/dev/null";
         description = "Specify the log file name. Also 'stdout' can be used to force Redis to log on the standard output.";
         example = "/var/log/redis.log";
         type = with types; string;
       };
 
+      syslog = mkOption {
+        default = true;
+        description = "Enable logging to the system logger.";
+        type = with types; bool;
+      };
+
       databases = mkOption {
         default = 16;
         description = "Set the number of databases.";
@@ -177,8 +184,9 @@ in
 
   config = mkIf config.services.redis.enable {
 
-    users.extraUsers = singleton
+    users.extraUsers.redis =
       { name = cfg.user;
+        uid = config.ids.uids.redis;
         description = "Redis database user";
       };
 

nixos/modules/services/games/ghost-one.nix

@@ -21,7 +21,8 @@ in
 
       language = mkOption {
         default = "English";
-        check = lang: elem lang [ "English" "Spanish" "Russian" "Serbian" "Turkish" ];
+        type = types.addCheck types.str
+          (lang: elem lang [ "English" "Spanish" "Russian" "Serbian" "Turkish" ]);
         description = "The language of bot messages: English, Spanish, Russian, Serbian or Turkish.";
       };
 

nixos/modules/services/hardware/acpid.nix

@@ -66,21 +66,25 @@ in
     services.acpid = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = "Whether to enable the ACPI daemon.";
       };
 
       powerEventCommands = mkOption {
+        type = types.lines;
         default = "";
         description = "Shell commands to execute on a button/power.* event.";
       };
 
       lidEventCommands = mkOption {
+        type = types.lines;
         default = "";
         description = "Shell commands to execute on a button/lid.* event.";
       };
 
       acEventCommands = mkOption {
+        type = types.lines;
         default = "";
         description = "Shell commands to execute on an ac_adapter.* event.";
       };

nixos/modules/services/hardware/bluetooth.nix

@@ -9,6 +9,7 @@ with pkgs.lib;
   options = {
 
     hardware.bluetooth.enable = mkOption {
+      type = types.bool;
       default = false;
       description = "Whether to enable support for Bluetooth.";
     };

nixos/modules/services/hardware/sane.nix

@@ -2,6 +2,12 @@
 
 with pkgs.lib;
 
+let
+
+  pkg = if config.hardware.sane.snapshot then pkgs.saneBackendsGit else pkgs.saneBackends;
+
+in
+
 {
 
   ###### interface
@@ -9,11 +15,13 @@ with pkgs.lib;
   options = {
 
     hardware.sane.enable = mkOption {
+      type = types.bool;
       default = false;
       description = "Enable support for SANE scanners.";
     };
 
     hardware.sane.snapshot = mkOption {
+      type = types.bool;
       default = false;
       description = "Use a development snapshot of SANE scanner drivers.";
     };
@@ -23,18 +31,13 @@ with pkgs.lib;
 
   ###### implementation
 
-    config = let pkg = if config.hardware.sane.snapshot
+  config = mkIf config.hardware.sane.enable {
-                          then pkgs.saneBackendsGit
-                          else pkgs.saneBackends;
-      in mkIf config.hardware.sane.enable {
-           environment.systemPackages = [ pkg ];
-           services.udev.packages = [ pkg ];
-           
-           users.extraGroups = singleton {
-             name = "scanner";
-             gid = config.ids.gids.scanner;
-           };
 
-      };
+    environment.systemPackages = [ pkg ];
+    services.udev.packages = [ pkg ];
+
+    users.extraGroups."scanner".gid = config.ids.gids.scanner;
+
+  };
 
 }

nixos/modules/services/hardware/udev.nix

@@ -114,6 +114,7 @@ in
   options = {
 
     boot.hardwareScan = mkOption {
+      type = types.bool;
       default = true;
       description = ''
         Whether to try to load kernel modules for all detected hardware.
@@ -126,8 +127,8 @@ in
     services.udev = {
 
       packages = mkOption {
+        type = types.listOf types.path;
         default = [];
-        merge = mergeListOption;
         description = ''
           List of packages containing <command>udev</command> rules.
           All files found in
@@ -138,8 +139,8 @@ in
       };
 
       path = mkOption {
+        type = types.listOf types.path;
         default = [];
-        merge = mergeListOption;
         description = ''
           Packages added to the <envar>PATH</envar> environment variable when
           executing programs from Udev rules.
@@ -162,9 +163,9 @@ in
     };
 
     hardware.firmware = mkOption {
+      type = types.listOf types.path;
       default = [];
       example = [ "/root/my-firmware" ];
-      merge = mergeListOption;
       description = ''
         List of directories containing firmware files.  Such files
         will be loaded automatically if the kernel asks for them

nixos/modules/services/hardware/udisks.nix

@@ -13,6 +13,7 @@ with pkgs.lib;
     services.udisks = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to enable Udisks, a DBus service that allows

nixos/modules/services/hardware/udisks2.nix

@@ -13,6 +13,7 @@ with pkgs.lib;
     services.udisks2 = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to enable Udisks, a DBus service that allows

nixos/modules/services/hardware/upower.nix

@@ -13,6 +13,7 @@ with pkgs.lib;
     services.upower = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to enable Upower, a DBus service that provides power

nixos/modules/services/logging/logcheck.nix

@@ -52,7 +52,7 @@ let
 
   levelOption = mkOption {
     default = "server";
-    type = types.uniq types.string;
+    type = types.str;
     description = ''
       Set the logcheck level. Either "workstation", "server", or "paranoid".
     '';
@@ -63,7 +63,7 @@ let
 
     regex = mkOption {
       default = "";
-      type = types.uniq types.string;
+      type = types.str;
       description = ''
         Regex specifying which log lines to ignore.
       '';
@@ -73,7 +73,7 @@ let
   ignoreCronOptions = {
     user = mkOption {
       default = "root";
-      type = types.uniq types.string;
+      type = types.str;
       description = ''
         User that runs the cronjob.
       '';
@@ -81,7 +81,7 @@ let
 
     cmdline = mkOption {
       default = "";
-      type = types.uniq types.string;
+      type = types.str;
       description = ''
         Command line for the cron job. Will be turned into a regex for the logcheck ignore rule.
       '';
@@ -89,7 +89,7 @@ let
 
     timeArgs = mkOption {
       default = null;
-      type = types.nullOr (types.uniq types.string);
+      type = types.nullOr (types.str);
       example = "02 06 * * *";
       description = ''
         "min hr dom mon dow" crontab time args, to auto-create a cronjob too.
@@ -112,7 +112,7 @@ in
 
       user = mkOption {
         default = "logcheck";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           Username for the logcheck user.
         '';
@@ -121,7 +121,7 @@ in
       timeOfDay = mkOption {
         default = "*";
         example = "6";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           Time of day to run logcheck. A logcheck will be scheduled at xx:02 each day.
           Leave default (*) to run every hour. Of course when nothing special was logged,
@@ -132,7 +132,7 @@ in
       mailTo = mkOption {
         default = "root";
         example = "you@domain.com";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           Email address to send reports to.
         '';
@@ -140,7 +140,7 @@ in
 
       level = mkOption {
         default = "server";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           Set the logcheck level. Either "workstation", "server", or "paranoid".
         '';

nixos/modules/services/logging/logstash.nix

@@ -99,7 +99,7 @@ in
           mkHash functions, which take a string representation of a float and an
           attrset, respectively.
         '';
-        merge = mergeConfigs;
+        apply = mergeConfigs;
       };
 
       filterConfig = mkOption {
@@ -109,7 +109,7 @@ in
           representing a logstash configuration's filter section.
           See inputConfig description for details.
         '';
-        merge = mergeConfigs;
+        apply = mergeConfigs;
       };
 
       outputConfig = mkOption {
@@ -119,7 +119,7 @@ in
           representing a logstash configuration's output section.
           See inputConfig description for details.
         '';
-        merge = mergeConfigs;
+        apply = mergeConfigs;
       };
     };
   };

nixos/modules/services/logging/syslogd.nix

@@ -46,7 +46,7 @@ in
       };
 
       tty = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         default = "tty10";
         description = ''
           The tty device on which syslogd will print important log
@@ -55,7 +55,7 @@ in
       };
 
       defaultConfig = mkOption {
-        type = types.string;
+        type = types.lines;
         default = defaultConf;
         description = ''
           The default <filename>syslog.conf</filename> file configures a
@@ -73,7 +73,7 @@ in
       };
 
       extraConfig = mkOption {
-        type = types.string;
+        type = types.lines;
         default = "";
         example = "news.* -/var/log/news";
         description = ''

nixos/modules/services/mail/freepops.nix

@@ -35,7 +35,7 @@ in
 
       bind = mkOption {
         default = "0.0.0.0";
-        type = with types; uniq string;
+        type = types.str;
         description = ''
           Bind over an IPv4 address instead of any.
         '';
@@ -44,7 +44,7 @@ in
       logFile = mkOption {
         default = "/var/log/freepopsd";
         example = "syslog";
-        type = with types; uniq string;
+        type = types.str;
         description = ''
           Filename of the log file or syslog to rely on the logging daemon.
         '';
@@ -53,7 +53,7 @@ in
       suid = {
         user = mkOption {
           default = "nobody";
-          type = with types; uniq string;
+          type = types.str;
           description = ''
             User name under which freepopsd will be after binding the port.
           '';
@@ -61,7 +61,7 @@ in
 
         group = mkOption {
           default = "nogroup";
-          type = with types; uniq string;
+          type = types.str;
           description = ''
             Group under which freepopsd will be after binding the port.
           '';

nixos/modules/services/misc/nix-daemon.nix

@@ -6,7 +6,7 @@ let
 
   cfg = config.nix;
 
-  inherit (config.environment) nix;
+  nix = cfg.package;
 
   makeNixBuildUser = nr:
     { name = "nixbld${toString nr}";
@@ -55,19 +55,20 @@ in
 
   options = {
 
-    environment.nix = mkOption {
-      default = pkgs.nix;
-      merge = mergeOneOption;
-      description = ''
-        This option specifies the Nix package instance to use throughout the system.
-      '';
-    };
-
     nix = {
 
+      package = mkOption {
+        type = types.path;
+        default = pkgs.nix;
+        description = ''
+          This option specifies the Nix package instance to use throughout the system.
+        '';
+      };
+
       maxJobs = mkOption {
+        type = types.int;
         default = 1;
-        example = 2;
+        example = 64;
         description = "
           This option defines the maximum number of jobs that Nix will try
           to build in parallel.  The default is 1.  You should generally
@@ -77,8 +78,8 @@ in
       };
 
       useChroot = mkOption {
+        type = types.bool;
         default = false;
-        example = true;
         description = "
           If set, Nix will perform builds in a chroot-environment that it
           will set up automatically for each build.  This prevents
@@ -88,6 +89,7 @@ in
       };
 
       chrootDirs = mkOption {
+        type = types.listOf types.str;
         default = [];
         example = [ "/dev" "/proc" ];
         description =
@@ -98,15 +100,17 @@ in
       };
 
       extraOptions = mkOption {
+        type = types.lines;
         default = "";
-        example = "
+        example = ''
           gc-keep-outputs = true
           gc-keep-derivations = true
-        ";
+        '';
         description = "Additional text appended to <filename>nix.conf</filename>.";
       };
 
       distributedBuilds = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to distribute builds to the machines listed in
@@ -115,22 +119,25 @@ in
       };
 
       daemonNiceLevel = mkOption {
+        type = types.int;
         default = 0;
-        description = "
+        description = ''
           Nix daemon process priority. This priority propagates to build processes.
           0 is the default Unix process priority, 20 is the lowest.
-        ";
+        '';
       };
 
       daemonIONiceLevel = mkOption {
+        type = types.int;
         default = 0;
-        description = "
+        description = ''
           Nix daemon process I/O priority. This priority propagates to build processes.
           0 is the default Unix process I/O priority, 7 is the lowest.
-        ";
+        '';
       };
 
       buildMachines = mkOption {
+        type = types.listOf types.attrs;
         default = [];
         example = [
           { hostName = "voila.labs.cs.uu.nl";
@@ -160,7 +167,7 @@ in
           user name to be used for the SSH connection
           (<varname>sshUser</varname>), the Nix system type
           (<varname>system</varname>, e.g.,
-          <literal>\"i686-linux\"</literal>), the maximum number of
+          <literal>"i686-linux"</literal>), the maximum number of
           jobs to be run in parallel on that machine
           (<varname>maxJobs</varname>), the path to the SSH private
           key to be used to connect (<varname>sshKey</varname>), a
@@ -176,24 +183,26 @@ in
       };
 
       proxy = mkOption {
+        type = types.str;
         default = "";
-        description = "
+        description = ''
           This option specifies the proxy to use for fetchurl. The real effect
           is just exporting http_proxy, https_proxy and ftp_proxy with that
           value.
-        ";
+        '';
         example = "http://127.0.0.1:3128";
       };
 
       # Environment variables for running Nix.
       envVars = mkOption {
+        type = types.attrs;
         internal = true;
         default = {};
-        type = types.attrs;
         description = "Environment variables used by Nix.";
       };
 
       nrBuildUsers = mkOption {
+        type = types.int;
         default = 10;
         description = ''
           Number of <literal>nixbld</literal> user accounts created to
@@ -204,6 +213,7 @@ in
       };
 
       readOnlyStore = mkOption {
+        type = types.bool;
         default = true;
         description = ''
           If set, NixOS will enforce the immutability of the Nix store
@@ -214,8 +224,8 @@ in
       };
 
       binaryCaches = mkOption {
+        type = types.listOf types.str;
         default = [ http://cache.nixos.org/ ];
-        type = types.listOf types.string;
         description = ''
           List of binary cache URLs used to obtain pre-built binaries
           of Nix packages.
@@ -223,9 +233,9 @@ in
       };
 
       trustedBinaryCaches = mkOption {
+        type = types.listOf types.str;
         default = [ ];
         example = [ http://hydra.nixos.org/ ];
-        type = types.listOf types.string;
         description = ''
           List of binary cache URLs that non-root users can use (in
           addition to those specified using
@@ -302,7 +312,7 @@ in
       }
 
       // optionalAttrs cfg.distributedBuilds {
-        NIX_BUILD_HOOK = "${config.environment.nix}/libexec/nix/build-remote.pl";
+        NIX_BUILD_HOOK = "${nix}/libexec/nix/build-remote.pl";
         NIX_REMOTE_SYSTEMS = "/etc/nix/machines";
         NIX_CURRENT_LOAD = "/run/nix/current-load";
       }

nixos/modules/services/misc/nix-gc.nix

@@ -22,7 +22,7 @@ in
 
       dates = mkOption {
         default = "03:15";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           Specification (in the format described by
           <citerefentry><refentrytitle>systemd.time</refentrytitle>
@@ -34,7 +34,7 @@ in
       options = mkOption {
         default = "";
         example = "--max-freed $((64 * 1024**3))";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           Options given to <filename>nix-collect-garbage</filename> when the
           garbage collector is run automatically.
@@ -52,7 +52,7 @@ in
 
     systemd.services.nix-gc =
       { description = "Nix Garbage Collector";
-        script = "exec ${config.environment.nix}/bin/nix-collect-garbage ${cfg.options}";
+        script = "exec ${config.nix.package}/bin/nix-collect-garbage ${cfg.options}";
         startAt = optionalString cfg.automatic cfg.dates;
       };
 

nixos/modules/services/misc/nixos-manual.nix

@@ -16,13 +16,15 @@ let
       system.nixosRevision = config.system.nixosRevision;
     };
 
+  eval = evalModules {
+    modules = [ versionModule ] ++ baseModules;
+    args = (removeAttrs extraArgs ["config" "options"]) // { modules = [ ]; };
+  };
+
   manual = import ../../../doc/manual {
     inherit pkgs;
     revision = config.system.nixosRevision;
-    options = (fixMergeModules ([ versionModule ] ++ baseModules)
+    options = eval.options;
-      (removeAttrs extraArgs ["config" "options"]) // {
-        modules = [ ];
-      }).options;
   };
 
   entry = "${manual.manual}/share/doc/nixos/manual.html";
@@ -51,14 +53,15 @@ in
   options = {
 
     services.nixosManual.enable = mkOption {
-      default = true;
       type = types.bool;
+      default = true;
       description = ''
         Whether to build the NixOS manual pages.
       '';
     };
 
     services.nixosManual.showManual = mkOption {
+      type = types.bool;
       default = false;
       description = ''
         Whether to show the NixOS manual on one of the virtual
@@ -74,6 +77,7 @@ in
     };
 
     services.nixosManual.browser = mkOption {
+      type = types.path;
       default = "${pkgs.w3m}/bin/w3m";
       description = ''
         Browser used to show the manual.

nixos/modules/services/misc/rogue.nix

@@ -17,6 +17,7 @@ in
   options = {
 
     services.rogue.enable = mkOption {
+      type = types.bool;
       default = false;
       description = ''
         Whether to enable the Rogue game on one of the virtual
@@ -25,6 +26,7 @@ in
     };
 
     services.rogue.tty = mkOption {
+      type = types.str;
       default = "tty9";
       description = ''
         Virtual console on which to run Rogue.

nixos/modules/services/misc/synergy.nix

@@ -22,58 +22,56 @@ in
         enable = mkOption {
           default = false;
           description = "
-            Whether to enable the synergy client (receive keyboard and mouse events from a synergy server)
+            Whether to enable the Synergy client (receive keyboard and mouse events from a Synergy server).
           ";
         };
         screenName = mkOption {
           default = "";
-          description = "
+          description = ''
-            use screen-name instead the hostname to identify
+            Use the given name instead of the hostname to identify
             ourselves to the server.
-            ";
+          '';
         };
         serverAddress = mkOption {
-          description = "
+          description = ''
             The server address is of the form: [hostname][:port].  The
             hostname must be the address or hostname of the server.  The
             port overrides the default port, 24800.
-          ";
+          '';
         };
         autoStart = mkOption {
           default = true;
           type = types.bool;
-          description = "Whether synergy-client should be started automatically.";
+          description = "Whether the Synergy client should be started automatically.";
         };
       };
 
       server = {
         enable = mkOption {
           default = false;
-          description = "
+          description = ''
-            Whether to enable the synergy server (send keyboard and mouse events)
+            Whether to enable the Synergy server (send keyboard and mouse events).
-          ";
+          '';
         };
         configFile = mkOption {
           default = "/etc/synergy-server.conf";
-          description = "
+          description = "The Synergy server configuration file.";
-            The synergy server configuration file. open upstart-jobs/synergy.nix to see an example
-          ";
         };
         screenName = mkOption {
           default = "";
-          description = "
+          description = ''
-            use screen-name instead the hostname to identify
+            Use the given name instead of the hostname to identify
             this screen in the configuration.
-            ";
+          '';
         };
         address = mkOption {
           default = "";
-          description = "listen for clients on the given address";
+          description = "Address on which to listen for clients.";
         };
         autoStart = mkOption {
           default = true;
           type = types.bool;
-          description = "Whether synergy-server should be started automatically.";
+          description = "Whether the Synergy server should be started automatically.";
         };
       };
     };

nixos/modules/services/monitoring/dd-agent.nix

@@ -26,7 +26,7 @@ in {
 
       example = "ae0aa6a8f08efa988ba0a17578f009ab";
 
-      type = types.uniq types.string;
+      type = types.str;
     };
 
     hostname = mkOption {

nixos/modules/services/monitoring/graphite.nix

@@ -8,7 +8,7 @@ let
 
   dataDir = "/var/db/graphite";
   carbonOpts = name: with config.ids; ''
-    --nodaemon --syslog --prefix=${name} \
+    --nodaemon --syslog --prefix=${name} --pidfile /var/run/${name}.pid \
     --uid ${toString uids.graphite} --gid ${toString uids.graphite} ${name}
   '';
   carbonEnv = {
@@ -32,13 +32,13 @@ in {
       host = mkOption {
         description = "Graphite web frontend listen address";
         default = "127.0.0.1";
-        types = type.uniq types.string;
+        type = types.str;
       };
 
       port = mkOption {
         description = "Graphite web frontend port";
         default = "8080";
-        types = type.uniq types.string;
+        type = types.str;
       };
     };
 
@@ -52,8 +52,11 @@ in {
           PICKLE_RECEIVER_INTERFACE = 127.0.0.1
           LINE_RECEIVER_INTERFACE = 127.0.0.1
           CACHE_QUERY_INTERFACE = 127.0.0.1
+          # Do not log every update
+          LOG_UPDATES = False
+          LOG_CACHE_HITS = False
         '';
-        type = types.uniq types.string;
+        type = types.str;
       };
 
       enableCache = mkOption {

nixos/modules/services/monitoring/smartd.nix

@@ -12,16 +12,15 @@ let
 
       device = mkOption {
         example = "/dev/sda";
-        type = types.string;
+        type = types.str;
         description = "Location of the device.";
       };
 
       options = mkOption {
         default = "";
         example = "-d sat";
-        type = types.string;
+        type = types.separatedString " ";
-        merge = pkgs.lib.concatStringsSep " ";
+        description = "Options that determine how smartd monitors the device.";
-        description = "Options that determine how smartd monitors the device";
       };
     };
 

nixos/modules/services/monitoring/statsd.nix

@@ -36,7 +36,7 @@ in
     host = mkOption {
       description = "Address that statsd listens on over UDP";
       default = "127.0.0.1";
-      type = types.uniq types.string;
+      type = types.str;
     };
 
     port = mkOption {
@@ -48,7 +48,7 @@ in
     mgmt_address = mkOption {
       description = "Address to run managment TCP interface on";
       default = "127.0.0.1";
-      type = types.uniq types.string;
+      type = types.str;
     };
 
     mgmt_port = mkOption {
@@ -65,7 +65,7 @@ in
     graphiteHost = mkOption {
       description = "Hostname or IP of Graphite server";
       default = "127.0.0.1";
-      type = types.uniq types.string;
+      type = types.str;
     };
 
     graphitePort = mkOption {
@@ -77,7 +77,7 @@ in
     extraConfig = mkOption {
       default = "";
       description = "Extra configuration options for statsd";
-      type = types.uniq types.string;
+      type = types.str;
     };
 
   };

nixos/modules/services/monitoring/ups.nix

@@ -15,7 +15,7 @@ let
       # This can be infered from the UPS model by looking at
       # /nix/store/nut/share/driver.list
       driver = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           Specify the program to run to talk to this UPS.  apcsmart,
           bestups, and sec are some examples.
@@ -23,7 +23,7 @@ let
       };
 
       port = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           The serial port to which your UPS is connected.  /dev/ttyS0 is
           usually the first port on Linux boxes, for example.
@@ -115,7 +115,7 @@ in
       # This option is not used yet.
       mode = mkOption {
         default = "standalone";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           The MODE determines which part of the NUT is to be started, and
           which configuration files must be modified.
@@ -142,7 +142,7 @@ in
 
       schedulerRules = mkOption {
         example = "/etc/nixos/upssched.conf";
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           File which contains the rules to handle UPS events.
         '';

nixos/modules/services/networking/avahi-daemon.nix

@@ -50,7 +50,7 @@ in
       };
 
       hostName = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         description = ''Host name advertised on the LAN.'';
       };
 

nixos/modules/services/networking/bitlbee.nix

@@ -64,7 +64,7 @@ in
 
       authMode = mkOption {
         default = "Open";
-        check = authModeCheck;
+        type = types.addCheck types.str authModeCheck;
         description = ''
           The following authentication modes are available:
             Open -- Accept connections from anyone, use NickServ for user authentication.

nixos/modules/services/networking/cntlm.nix

@@ -39,7 +39,7 @@ in
       };
 
       netbios_hostname = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         description = ''
           The hostname of your machine.
         '';

nixos/modules/services/networking/dhclient.nix

@@ -1,111 +0,0 @@
-{ config, pkgs, ... }:
-
-with pkgs.lib;
-
-let
-
-  inherit (pkgs) nettools dhcp lib;
-
-  # Don't start dhclient on explicitly configured interfaces or on
-  # interfaces that are part of a bridge.
-  ignoredInterfaces =
-    map (i: i.name) (lib.filter (i: i ? ipAddress && i.ipAddress != "" ) config.networking.interfaces)
-    ++ concatLists (attrValues (mapAttrs (n: v: v.interfaces) config.networking.bridges));
-
-  stateDir = "/var/lib/dhcp"; # Don't use /var/state/dhcp; not FHS-compliant.
-
-  dhclientExitHooks = pkgs.writeText "dhclient-exit-hooks"
-    ''
-      #echo "$reason" >> /tmp/dhcp-exit
-      #echo "$exit_status" >> /tmp/dhcp-exit
-
-      if test "$reason" = BOUND -o "$reason" = REBOOT; then
-          # Restart ntpd.  (The "ip-up" event below will trigger the
-          # restart.)  We need to restart it to make sure that it will
-          # actually do something: if ntpd cannot resolve the server
-          # hostnames in its config file, then it will never do
-          # anything ever again ("couldn't resolve ..., giving up on
-          # it"), so we silently lose time synchronisation.
-          ${config.system.build.upstart}/sbin/initctl stop ntpd
-
-          ${config.system.build.upstart}/sbin/initctl emit -n ip-up
-      fi
-
-      if test "$reason" = EXPIRE -o "$reason" = RELEASE; then
-          ${config.system.build.upstart}/sbin/initctl emit -n ip-down
-      fi
-    '';
-
-in
-
-{
-
-  ###### implementation
-
-  config = mkIf config.networking.useDHCP {
-
-    # dhclient barfs if /proc/net/if_inet6 doesn't exist.
-    boot.kernelModules = [ "ipv6" ];
-
-    jobs.dhclient =
-      { startOn = "started network-interfaces";
-        stopOn = "stopping network-interfaces";
-
-        path = [ dhcp ];
-
-        script =
-          ''
-            # Determine the interface on which to start dhclient.
-            interfaces=
-
-            for i in $(cd /sys/class/net && ls -d *); do
-                # Only run dhclient on interfaces of type ARPHRD_ETHER
-                # (1), i.e. Ethernet.  Ignore peth* devices; on Xen,
-                # they're renamed physical Ethernet cards used for
-                # bridging.  Likewise for vif* and tap* (Xen) and
-                # virbr* and vnet* (libvirt).
-                if [ "$(cat /sys/class/net/$i/type)" = 1 ]; then
-                    if ! for j in ${toString ignoredInterfaces}; do echo $j; done | grep -F -x -q "$i" &&
-                       ! echo "$i" | grep -x -q "peth.*\|vif.*\|tap.*\|virbr.*\|vnet.*";
-		    then
-                        echo "Running dhclient on $i"
-                        interfaces="$interfaces $i"
-                    fi
-                fi
-            done
-
-            if test -z "$interfaces"; then
-                echo 'No interfaces on which to start dhclient!'
-                exit 1
-            fi
-
-            mkdir -m 755 -p ${stateDir}
-
-            exec dhclient -d $interfaces -e "PATH=$PATH" -lf ${stateDir}/dhclient.leases -sf ${dhcp}/sbin/dhclient-script
-          '';
-      };
-
-    environment.systemPackages = [dhcp];
-
-    environment.etc =
-      [ # Dhclient hooks for emitting ip-up/ip-down events.
-        { source = dhclientExitHooks;
-          target = "dhclient-exit-hooks";
-        }
-      ];
-
-    powerManagement.resumeCommands =
-      ''
-        ${config.system.build.upstart}/sbin/restart dhclient
-      '';
-
-    networking.interfaceMonitor.commands =
-      ''
-        if [ "$status" = up ]; then
-          ${config.system.build.upstart}/sbin/restart dhclient
-        fi
-      '';
-
-  };
-
-}

nixos/modules/services/networking/dhcpcd.nix

@@ -6,7 +6,7 @@ let
 
   inherit (pkgs) dhcpcd;
 
-  # Don't start dhclient on explicitly configured interfaces or on
+  # Don't start dhcpcd on explicitly configured interfaces or on
   # interfaces that are part of a bridge.
   ignoredInterfaces =
     map (i: i.name) (filter (i: i.ipAddress != null) (attrValues config.networking.interfaces))

nixos/modules/services/networking/dhcpd.nix

@@ -15,7 +15,7 @@ let
       authoritative;
       ddns-update-style ad-hoc;
       log-facility local1; # see dhcpd.nix
-      
+
       ${cfg.extraConfig}
 
       ${pkgs.lib.concatMapStrings
@@ -30,13 +30,13 @@ let
     '';
 
 in
-  
+
 {
 
   ###### interface
 
   options = {
-  
+
     services.dhcpd = {
 
       enable = mkOption {
@@ -48,16 +48,16 @@ in
 
       extraConfig = mkOption {
         default = "";
-        example = "
+        example = ''
           option subnet-mask 255.255.255.0;
           option broadcast-address 192.168.1.255;
           option routers 192.168.1.5;
           option domain-name-servers 130.161.158.4, 130.161.33.17, 130.161.180.1;
-          option domain-name \"example.org\";
+          option domain-name "example.org";
           subnet 192.168.1.0 netmask 255.255.255.0 {
             range 192.168.1.100 192.168.1.200;
           }
-        ";
+        '';
         description = "
           Extra text to be appended to the DHCP server configuration
           file.  Currently, you almost certainly need to specify
@@ -100,9 +100,9 @@ in
       };
 
     };
-    
+
   };
-  
+
 
   ###### implementation
 
@@ -127,5 +127,5 @@ in
       };
 
   };
-  
+
 }

nixos/modules/services/networking/firewall.nix

@@ -53,6 +53,7 @@ in
   options = {
 
     networking.firewall.enable = mkOption {
+      type = types.bool;
       default = false;
       description =
         ''
@@ -64,6 +65,7 @@ in
     };
 
     networking.firewall.logRefusedConnections = mkOption {
+      type = types.bool;
       default = true;
       description =
         ''
@@ -72,6 +74,7 @@ in
     };
 
     networking.firewall.logRefusedPackets = mkOption {
+      type = types.bool;
       default = false;
       description =
         ''
@@ -82,6 +85,7 @@ in
     };
 
     networking.firewall.logRefusedUnicastsOnly = mkOption {
+      type = types.bool;
       default = true;
       description =
         ''
@@ -93,6 +97,7 @@ in
     };
 
     networking.firewall.rejectPackets = mkOption {
+      type = types.bool;
       default = false;
       description =
         ''
@@ -193,6 +198,7 @@ in
     };
 
     networking.firewall.extraCommands = mkOption {
+      type = types.lines;
       default = "";
       example = "iptables -A INPUT -p icmp -j ACCEPT";
       description =
@@ -209,11 +215,8 @@ in
 
   ###### implementation
 
-  # !!! Maybe if `enable' is false, the firewall should still be built
+  # FIXME: Maybe if `enable' is false, the firewall should still be
-  # but not started by default.  However, currently nixos-rebuild
+  # built but not started by default?
-  # doesn't deal with such Upstart jobs properly (it starts them if
-  # they are changed, regardless of whether the start condition
-  # holds).
   config = mkIf cfg.enable {
 
     networking.firewall.trustedInterfaces = [ "lo" ];

nixos/modules/services/networking/gogoclient.nix

@@ -15,38 +15,35 @@ in
         default = false;
         type =  types.bool;
         description = ''
-          Enable the gogoclient ipv6 tunnel.
+          Enable the gogoCLIENT IPv6 tunnel.
         '';
       };
       autorun = mkOption {
         default = true;
-        description = "
+        description = ''
-          Switch to false to create upstart-job and configuration,
+          Whether to automatically start the tunnel.
-          but not run it automatically
+        '';
-        ";
       };
 
       username = mkOption {
         default = "";
-        description = "
+        description = ''
           Your Gateway6 login name, if any.
-        ";
+        '';
       };
 
       password = mkOption {
         default = "";
         type = types.string;
-        description = "
+        description = ''
-          Path to a file (as a string), containing your gogonet password, if any.
+          Path to a file (as a string), containing your gogoNET password, if any.
-        ";
+        '';
       };
 
       server = mkOption {
         default = "anonymous.freenet6.net";
         example = "broker.freenet6.net";
-        description = "
+        description = "The Gateway6 server to be used.";
-          Used Gateway6 server.
-        ";
       };
     };
   };

nixos/modules/services/networking/haproxy.nix

@@ -0,0 +1,87 @@
+{ config, pkgs, ...}:
+let
+  cfg = config.services.haproxy;
+  haproxyCfg = pkgs.writeText "haproxy.conf" cfg.config;
+in
+with pkgs.lib;
+{
+  options = {
+    services.haproxy = {
+
+      enable = mkOption {
+        default = false;
+        description = "
+          Enable the HAProxy.
+        ";
+      };
+
+      config = mkOption {
+        default =
+          ''
+          global
+            log 127.0.0.1 local6
+            maxconn  24000
+            daemon
+            nbproc 1
+
+          defaults
+            mode http
+            option httpclose
+
+            # Remove requests from the queue if people press stop button
+            option abortonclose
+
+            # Try to connect this many times on failure
+            retries 3
+
+            # If a client is bound to a particular backend but it goes down,
+            # send them to a different one
+            option redispatch
+
+            monitor-uri /haproxy-ping
+
+            timeout connect 7s
+            timeout queue   300s
+            timeout client  300s
+            timeout server  300s
+
+            # Enable status page at this URL, on the port HAProxy is bound to
+            stats enable
+            stats uri /haproxy-status
+            stats refresh 5s
+            stats realm Haproxy statistics
+          '';
+        description = "
+          Default configuration.
+        ";
+      };
+
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    systemd.services.haproxy = {
+      description = "HAProxy";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        Type = "forking";
+        PIDFile = "/var/run/haproxy.pid";
+        ExecStartPre = "${pkgs.haproxy}/sbin/haproxy -c -q -f ${haproxyCfg}";
+        ExecStart = "${pkgs.haproxy}/sbin/haproxy -D -f ${haproxyCfg} -p /var/run/haproxy.pid";
+        ExecReload = "-${pkgs.bash}/bin/bash -c \"exec ${pkgs.haproxy}/sbin/haproxy -D -f ${haproxyCfg} -p /var/run/haproxy.pid -sf $MAINPID\"";
+      };
+    };
+
+    environment.systemPackages = [ pkgs.haproxy ];
+
+    users.extraUsers.haproxy = {
+      group = "haproxy";
+      uid = config.ids.uids.haproxy;
+    };
+
+    users.extraGroups.haproxy.gid = config.ids.uids.haproxy;
+  };
+}

nixos/modules/services/networking/ifplugd.nix

@@ -9,10 +9,7 @@ let
   cfg = config.networking.interfaceMonitor;
 
   # The ifplugd action script, which is called whenever the link
-  # status changes (i.e., a cable is plugged in or unplugged).  We do
+  # status changes (i.e., a cable is plugged in or unplugged).
-  # nothing when a cable is unplugged.  When a cable is plugged in, we
-  # restart dhclient, which will hopefully give us a new IP address
-  # if appropriate.
   plugScript = pkgs.writeScript "ifplugd.action"
     ''
       #! ${pkgs.stdenv.shell}
@@ -30,17 +27,19 @@ in
   options = {
 
     networking.interfaceMonitor.enable = mkOption {
+      type = types.bool;
       default = false;
       description = ''
         If <literal>true</literal>, monitor Ethernet interfaces for
         cables being plugged in or unplugged.  When this occurs, the
-        <command>dhclient</command> service is restarted to
+        commands specified in
-        automatically obtain a new IP address.  This is useful for
+        <option>networking.interfaceMonitor.commands</option> are
-        roaming users (laptops).
+        executed.
       '';
     };
 
     networking.interfaceMonitor.beep = mkOption {
+      type = types.bool;
       default = false;
       description = ''
         If <literal>true</literal>, beep when an Ethernet cable is
@@ -49,6 +48,7 @@ in
     };
 
     networking.interfaceMonitor.commands = mkOption {
+      type = types.lines;
       default = "";
       description = ''
         Shell commands to be executed when the link status of an

nixos/modules/services/networking/iodined.nix

@@ -32,21 +32,21 @@ in
       };
 
       ip = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         default = "";
         description = "Assigned ip address or ip range";
         example = "172.16.10.1/24";
       };
 
       domain = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         default = "";
         description = "Domain or subdomain of which nameservers point to us";
         example = "tunnel.mydomain.com";
       };
 
       extraConfig = mkOption {
-        type = types.uniq types.string;
+        type = types.str;
         default = "";
         description = "Additional command line parameters";
         example = "-P mysecurepassword -l 192.168.1.10 -p 23";