Adding '--rename' option to 'functions' builtin.

Aim is to allow an existing function to be renamed, allowing some basic function chaining.

Example:

> function foo
     echo Hello
  end
> foo
Hello
> functions --rename foo bar
> foo
fish: Unknown command 'foo'
> bar
Hello
> functions --rename fish_prompt old_prompt
> function fish_prompt
      printf "{Boo!}%s" (old_prompt)
  end
{Boo!}>

Note in the last case, the new fish_prompt is calling its old definition.

1 files changed, 11 insertions, 0 deletions

diff --git a/function.h b/function.h
index 7e172948..31243663 100644
--- a/function.h
+++ b/function.h
@@ -131,4 +131,15 @@ array_list_t *function_get_named_arguments( const wchar_t *name );
 */
 int function_get_shadows( const wchar_t *name );
 
+/**
+   Creates a new function using the same definition as the specified function.
+   Returns non-zero if copy is successful.
+*/
+int function_copy( const wchar_t *name, const wchar_t *new_name );
+
+/** 
+   Renames the specified function.
+*/
+void function_rename( const wchar_t *name, const wchar_t *new_name );
+
 #endif