lua*Packages: Consolidate separate setup hooks together

- Lua packages now consistently use LUA_PATH/LUA_CPATH rather than a mix
  of those and NIX_LUA_PATH/NIX_LUA_CPATH
- Lua libraries are now consistently only added to the search path
variables if:
    1) The library actually has a corresponding directory to search
    2) The library is not already present in the search path
  This should help prevent the search paths from growing overly large
- Fixed bugs in some path helpers
- Changed the affected shell script indentation to 2 spaces; nixpkgs
  shell scripts are inconsistently split between 2 and 4 space
  indentation, but 2 matches better with the Nix expressions, so IMO it
  makes more sense

pkgs/development/interpreters/lua-5/setup-hook.sh

@@ -1,47 +1,47 @@
 # set -e
 
 nix_print() {
-    if [ ${NIX_DEBUG:-0} -ge $1 ]; then
-        echo "$2"
-    fi
+  if [ ${NIX_DEBUG:-0} -ge $1 ]; then
+    echo "$2"
+  fi
 }
 
 nix_debug() {
-    nix_print 3 "$1"
+  nix_print 3 "$1"
 }
 
 addToLuaSearchPathWithCustomDelimiter() {
-    local varName="$1"
-    local absPattern="$2"
-    # delete longest match starting from the lua placeholder '?'
-    local topDir="${absPattern%%\?*}"
+  local varName="$1"
+  local absPattern="$2"
+  # delete longest match starting from the lua placeholder '?'
+  local topDir="${absPattern%%\?*}"
 
-    # export only if the folder exists else LUA_PATH grows too big
-    if  [ ! -d "$topDir" ]; then return; fi
+  # export only if the folder exists else LUA_PATH/LUA_CPATH grow too large
+  if [[ ! -d "$topDir" ]]; then return; fi
 
-    export "${varName}=${!varName:+${!varName};}${absPattern}"
+  # export only if we haven't already got this dir in the search path
+  if [[ ${!varName} == *"$absPattern"* ]]; then return; fi
+
+  export "${varName}=${!varName:+${!varName};}${absPattern}"
 }
 
 addToLuaPath() {
-    local dir="$1"
+  local dir="$1"
 
-    if [[ ! -d "$dir" ]]; then
-        nix_debug "$dir not a directory abort"
-        return 0
-    fi
-    cd "$dir"
-    for pattern in @luapathsearchpaths@;
-    do
-        addToLuaSearchPathWithCustomDelimiter NIX_LUA_PATH "$PWD/$pattern"
-    done
+  if [[ ! -d "$dir" ]]; then
+    nix_debug "$dir not a directory abort"
+    return 0
+  fi
+  cd "$dir"
+  for pattern in @luapathsearchpaths@; do
+    addToLuaSearchPathWithCustomDelimiter LUA_PATH "$PWD/$pattern"
+  done
 
-    # LUA_CPATH
-    for pattern in @luacpathsearchpaths@;
-    do
-        addToLuaSearchPathWithCustomDelimiter NIX_LUA_CPATH "$PWD/$pattern"
-    done
-    cd - >/dev/null
+  # LUA_CPATH
+  for pattern in @luacpathsearchpaths@; do
+    addToLuaSearchPathWithCustomDelimiter LUA_CPATH "$PWD/$pattern"
+  done
+  cd - >/dev/null
 }
 
 addEnvHooks "$hostOffset" addToLuaPath
-