prepend_path allowing multiple paths to be specified at once

functions/_prepend_path.fish

-# Prepends the path to the specified path list. If no list specified, defaults to $PATH
+# NAME
+#      _prepend_path - adds a path to a list
+#
+# SYNOPSIS
+#      _prepend_path [-d --destination <destination path>] <path>
+#
+# DESCRIPTION
+#      Adds a path to a list.
+#      If no list specified, defaults to $PATH
+#
+# OPTIONS
+#      <path>
+#          Required. Specify the path to add to the list.
+#
+#      [<glob> [<operator> <glob>..]]
+#          Glob pattern to match when traversing the path path.
+#
+# OPERATORS
+#      -d <DESTINATION PATH>
+#          Should appear at the end if used. Specifies the name of the
+#          list to prepend the paths to.
+#          If not used, $PATH is assumed by default.
+#
+# EXAMPLES
+#      _prepend_path $path
+#          Add $path to $PATH
+#
+#      _prepend_path $path -d $fish_function_path
+#          Add $path to $fish_function_path
+#/
+
 function _prepend_path
-  set -l path PATH
+  set -l destination_path PATH #$PATH is the default destination path
+  set -l len (count $argv)
+  set -l path $argv
 
-  if test (echo $argv | wc -w) -eq 2
-    set path $argv[2]
+  if test $len -gt 2
+    switch $argv[-2]
+    case -d --destination
+      set destination_path $argv[-1]
+      set path $argv[1..-3]
+    end
   end
 
-  if test -d $argv[1]
-    if not contains $argv[1] $$path
-      set $path $argv[1] $$path
+  for path in $path
+    if test -d $path
+      if not contains $path $$destination_path
+        set $destination_path $path $$destination_path
+      end
     end
   end
 end

oh-my-fish.fish

@@ -6,16 +6,16 @@ function _fish_add_plugin
   set -l plugin $argv[1]
   set -l plugin_path "plugins/$plugin"
 
-  _prepend_path $fish_path/$plugin_path fish_function_path
-  _prepend_path $fish_custom/$plugin_path fish_function_path
+  _prepend_path $fish_path/$plugin_path -d fish_function_path
+  _prepend_path $fish_custom/$plugin_path -d fish_function_path
 end
 
 function _fish_add_completion
   set -l plugin $argv[1]
   set -l completion_path "plugins/$plugin/completions"
 
-  _prepend_path $fish_path/$completion_path fish_complete_path
-  _prepend_path $fish_custom/$completion_path fish_complete_path
+  _prepend_path $fish_path/$completion_path -d fish_complete_path
+  _prepend_path $fish_custom/$completion_path -d fish_complete_path
 end
 
 function _fish_source_plugin_load_file
@@ -32,8 +32,8 @@ function _fish_source_plugin_load_file
 end
 
 function _fish_load_theme
-  _prepend_path $fish_path/themes/$fish_theme fish_function_path
-  _prepend_path $fish_custom/themes/$fish_theme fish_function_path
+  _prepend_path $fish_path/themes/$fish_theme -d fish_function_path
+  _prepend_path $fish_custom/themes/$fish_theme -d fish_function_path
 end
 
 ###