Use enum values instead of plain numbers for the file lists's sort

Use enum values instead of plain numbers for the file lists's sort

2003-10-01  Federico Mena Quintero  <federico@ximian.com>

	* gtkfilechooserimpldefault.c (tree_selection_changed): Use enum
	values instead of plain numbers for the file lists's sort columns.
	(create_file_list): Likewise.
	(tree_selection_changed): Make the file list start up sorted by
	name, and don't specify a default sorting function, so that there
	is no unsorted order.  This is for consistency with Nautilus.
	(list_sort_column_changed_cb): Callback; we cache whether the sort
	order for the file list's name column is ascending or not.
	(compare_with_folders_first): New helper function to sort
	directories before files.
	(name_sort_func): Use compare_with_folders_first().
	(size_sort_func): Likewise.
	(mtime_sort_func): Likewise.

	Of course this callback mess would be easy in a real language:

	  (set-sort-func sortable NAME_COLUMN
	    (make-comparer impl (lambda (a b) (strcmp (get-name a) (get-name b)))))
	  (set-sort-func sortable SIZE_COLUMN
	    (make-comparer impl (lambda (a b) (compare (get-size a) (get-size b)))))
	  ... etc ...

	  (define (make-comparer impl f)
	    (lambda (a b)
	      (if (eq (is-dir? a) (is-dir? b))
	          (f a b)
		  (if (sort-ascending? impl)
		      (if (is-dir? a) -1 1)
		      (if (is-dir? a) 1 -1)))))