265 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			265 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
# Definitions related to run-time type checking.  Used in particular
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# to type-check NixOS configurations.
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with import ./lists.nix;
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with import ./attrsets.nix;
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with import ./options.nix;
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with import ./trivial.nix;
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with import ./strings.nix;
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with {inherit (import ./modules.nix) mergeDefinitions filterOverrides; };
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rec {
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  isType = type: x: (x._type or "") == type;
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  setType = typeName: value: value // {
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    _type = typeName;
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  };
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  isOptionType = isType "option-type";
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  mkOptionType =
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    { # Human-readable representation of the type.
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      name
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    , # Function applied to each definition that should return true if
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      # its type-correct, false otherwise.
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      check ? (x: true)
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    , # Merge a list of definitions together into a single value.
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      # This function is called with two arguments: the location of
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      # the option in the configuration as a list of strings
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      # (e.g. ["boot" "loader "grub" "enable"]), and a list of
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      # definition values and locations (e.g. [ { file = "/foo.nix";
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      # value = 1; } { file = "/bar.nix"; value = 2 } ]).
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      merge ? mergeDefaultOption
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    , # Return a flat list of sub-options.  Used to generate
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      # documentation.
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      getSubOptions ? prefix: {}
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    , # List of modules if any, or null if none.
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      getSubModules ? null
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    , # Function for building the same option type  with a different list of
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      # modules.
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      substSubModules ? m: null
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    }:
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    { _type = "option-type";
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      inherit name check merge getSubOptions getSubModules substSubModules;
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    };
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  types = rec {
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    unspecified = mkOptionType {
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      name = "unspecified";
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    };
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    bool = mkOptionType {
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      name = "boolean";
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      check = isBool;
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      merge = mergeEqualOption;
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    };
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    int = mkOptionType {
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      name = "integer";
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      check = isInt;
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      merge = mergeOneOption;
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    };
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    str = mkOptionType {
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      name = "string";
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      check = isString;
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      merge = mergeOneOption;
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    };
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    # Merge multiple definitions by concatenating them (with the given
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    # separator between the values).
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    separatedString = sep: mkOptionType {
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      name = "string";
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      check = isString;
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      merge = loc: defs: concatStringsSep sep (getValues defs);
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    };
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    lines = separatedString "\n";
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    commas = separatedString ",";
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    envVar = separatedString ":";
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    # Deprecated; should not be used because it quietly concatenates
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    # strings, which is usually not what you want.
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    string = separatedString "";
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    attrs = mkOptionType {
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      name = "attribute set";
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      check = isAttrs;
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      merge = loc: foldl' (res: def: mergeAttrs res def.value) {};
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    };
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    # derivation is a reserved keyword.
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    package = mkOptionType {
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      name = "derivation";
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      check = x: isDerivation x || isStorePath x;
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      merge = loc: defs:
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        let res = mergeOneOption loc defs;
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        in if isDerivation res then res else toDerivation res;
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    };
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    path = mkOptionType {
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      name = "path";
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      # Hacky: there is no ‘isPath’ primop.
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      check = x: builtins.substring 0 1 (toString x) == "/";
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      merge = mergeOneOption;
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    };
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    # drop this in the future:
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    list = builtins.trace "`types.list' is deprecated; use `types.listOf' instead" types.listOf;
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    listOf = elemType: mkOptionType {
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      name = "list of ${elemType.name}s";
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      check = isList;
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      merge = loc: defs:
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        map (x: x.value) (filter (x: x ? value) (concatLists (imap (n: def: imap (m: def':
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            (mergeDefinitions
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              (loc ++ ["[definition ${toString n}-entry ${toString m}]"])
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              elemType
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              [{ inherit (def) file; value = def'; }]
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            ).optionalValue
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          ) def.value) defs)));
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      getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
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      getSubModules = elemType.getSubModules;
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      substSubModules = m: listOf (elemType.substSubModules m);
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    };
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    attrsOf = elemType: mkOptionType {
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      name = "attribute set of ${elemType.name}s";
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      check = isAttrs;
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      merge = loc: defs:
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        mapAttrs (n: v: v.value) (filterAttrs (n: v: v ? value) (zipAttrsWith (name: defs:
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            (mergeDefinitions (loc ++ [name]) elemType defs).optionalValue
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          )
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          # Push down position info.
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          (map (def: listToAttrs (mapAttrsToList (n: def':
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            { name = n; value = { inherit (def) file; value = def'; }; }) def.value)) defs)));
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      getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
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      getSubModules = elemType.getSubModules;
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      substSubModules = m: attrsOf (elemType.substSubModules m);
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    };
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    # List or attribute set of ...
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    loaOf = elemType:
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      let
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        convertIfList = defIdx: def:
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          if isList def.value then
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            { inherit (def) file;
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              value = listToAttrs (
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                imap (elemIdx: elem:
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                  { name = elem.name or "unnamed-${toString defIdx}.${toString elemIdx}";
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                    value = elem;
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                  }) def.value);
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            }
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          else
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            def;
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        listOnly = listOf elemType;
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        attrOnly = attrsOf elemType;
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      in mkOptionType {
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        name = "list or attribute set of ${elemType.name}s";
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        check = x: isList x || isAttrs x;
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        merge = loc: defs: attrOnly.merge loc (imap convertIfList defs);
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        getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
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        getSubModules = elemType.getSubModules;
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        substSubModules = m: loaOf (elemType.substSubModules m);
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      };
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    # List or element of ...
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    loeOf = elemType: mkOptionType {
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      name = "element or list of ${elemType.name}s";
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      check = x: isList x || elemType.check x;
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      merge = loc: defs:
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        let
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          defs' = filterOverrides defs;
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          res = (head defs').value;
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        in
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        if isList res then concatLists (getValues defs')
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        else if lessThan 1 (length defs') then
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          throw "The option `${showOption loc}' is defined multiple times, in ${showFiles (getFiles defs)}."
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        else if !isString res then
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          throw "The option `${showOption loc}' does not have a string value, in ${showFiles (getFiles defs)}."
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        else res;
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    };
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    uniq = elemType: mkOptionType {
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      inherit (elemType) name check;
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      merge = mergeOneOption;
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      getSubOptions = elemType.getSubOptions;
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      getSubModules = elemType.getSubModules;
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      substSubModules = m: uniq (elemType.substSubModules m);
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    };
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    nullOr = elemType: mkOptionType {
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      name = "null or ${elemType.name}";
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      check = x: x == null || elemType.check x;
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      merge = loc: defs:
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        let nrNulls = count (def: def.value == null) defs; in
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        if nrNulls == length defs then null
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        else if nrNulls != 0 then
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          throw "The option `${showOption loc}' is defined both null and not null, in ${showFiles (getFiles defs)}."
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        else elemType.merge loc defs;
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      getSubOptions = elemType.getSubOptions;
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      getSubModules = elemType.getSubModules;
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      substSubModules = m: nullOr (elemType.substSubModules m);
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    };
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    submodule = opts:
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      let
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        opts' = toList opts;
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        inherit (import ./modules.nix) evalModules;
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      in
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      mkOptionType rec {
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        name = "submodule";
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        check = x: isAttrs x || isFunction x;
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        merge = loc: defs:
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          let
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            coerce = def: if isFunction def then def else { config = def; };
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            modules = opts' ++ map (def: { _file = def.file; imports = [(coerce def.value)]; }) defs;
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          in (evalModules {
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            inherit modules;
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            args.name = last loc;
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            prefix = loc;
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          }).config;
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        getSubOptions = prefix: (evalModules
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          { modules = opts'; inherit prefix;
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            # FIXME: hack to get shit to evaluate.
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            args = { name = ""; }; }).options;
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        getSubModules = opts';
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        substSubModules = m: submodule m;
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      };
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    enum = values:
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      let
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        show = v:
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               if builtins.isString v then ''"${v}"''
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          else if builtins.isInt v then builtins.toString v
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          else ''<${builtins.typeOf v}>'';
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      in
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      mkOptionType {
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        name = "one of ${concatMapStringsSep ", " show values}";
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        check = flip elem values;
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        merge = mergeOneOption;
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      };
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    either = t1: t2: mkOptionType {
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      name = "${t1.name} or ${t2.name}";
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      check = x: t1.check x || t2.check x;
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      merge = mergeOneOption;
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    };
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    # Obsolete alternative to configOf.  It takes its option
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    # declarations from the ‘options’ attribute of containing option
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    # declaration.
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    optionSet = mkOptionType {
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      name = /* builtins.trace "types.optionSet is deprecated; use types.submodule instead" */ "option set";
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    };
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    # Augment the given type with an additional type check function.
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    addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
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  };
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}
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