file_name_on_path

pl/swi.yap

@@ -6,6 +6,24 @@
 %	True if file Alias points to Dir.  Multiple solutions are
 %	generated with the longest directory first.
 
+%%	file_name_on_path(+File:atom, -OnPath) is det.
+%
+%	True if OnPath a description of File   based  on the file search
+%	path. This performs the inverse of absolute_file_name/3.
+
+prolog:file_name_on_path(Path, ShortId) :-
+	(   prolog:file_alias_path(Alias, Dir),
+	    atom_concat(Dir, Local, Path)
+	->  (   Alias == '.'
+	    ->  ShortId = Local
+	    ;   file_name_extension(Base, pl, Local)
+	    ->  ShortId =.. [Alias, Base]
+	    ;   ShortId =.. [Alias, Local]
+	    )
+	;   ShortId = Path
+	).
+
+
 :- dynamic
 	alias_cache/2.
 
@@ -25,7 +43,7 @@ build_alias_cache :-
 		search_path(Alias, Dir, AliasLen, DirLen), Ts),
 	sort(Ts, List0),
 	reverse(List0, List),
-	forall(member(t(_, _, Alias, Dir), List),
+	forall(lists:member(t(_, _, Alias, Dir), List),
 	       assert(alias_cache(Alias, Dir))).
 
 search_path('.', Here, 999, DirLen) :-
@@ -53,3 +71,11 @@ ensure_slash(Dir0, Dir) :-
 	atom_concat(Dir0, /, Dir).
 
 
+reverse(List, Reversed) :-
+	reverse(List, [], Reversed).
+
+reverse([], Reversed, Reversed).
+reverse([Head|Tail], Sofar, Reversed) :-
+	reverse(Tail, [Head|Sofar], Reversed).
+
+