From 7d3d9bcf41ecd66369f4472b7b99a29005cbc529 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADtor=20Santos=20Costa?= <vsc@dcc.fc.up.pt>
Date: Wed, 28 Mar 2012 14:35:09 +0100
Subject: [PATCH] fix module stuff.

---
 pl/boot.yap     | 12 +++++++++---
 pl/messages.yap |  2 ++
 pl/modules.yap  | 36 +++++++++++++++++++++---------------
 3 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/pl/boot.yap b/pl/boot.yap
index 011d2bab0..aeb23f838 100644
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -422,11 +422,17 @@ true :- true.
 	  '$compile'(G, L, G0, Mod)
 	 ).
 
+%
+% check if current module redefines an imported predicate.
+% and remove import.
+%
 '$not_imported'(H, Mod) :-
-	recorded('$import','$import'(NM,Mod,NH,H,_,_),_),
-	NM \= Mod, !,
+	recorded('$import','$import'(NM,Mod,NH,H,_,_),R),
+	NM \= Mod,
 	functor(NH,N,Ar),
-	'$do_error'(permission_error(modify, static_procedure, NM:N/Ar), consult).
+	print_message(warning,redefine_imported(Mod,NM,N/Ar)),
+	erase(R),
+	fail.
 '$not_imported'(_, _).
 
 
diff --git a/pl/messages.yap b/pl/messages.yap
index 889d91755..909548a82 100644
--- a/pl/messages.yap
+++ b/pl/messages.yap
@@ -126,6 +126,8 @@ system_message(functionality(Library)) -->
 	[  '~q not available' - [Library] ].
 system_message(import(Pred,To,From,private)) -->
 	[ 'Importing private predicate ~w:~w to ~w.' - [From,Pred,To] ].
+system_message(redefine_imported(M,M0,PI)) -->
+	[ 'Module ~w redefines imported predicate ~w:~w.' - [M,M0,PI] ].
 system_message(leash([])) -->
 	[ 'No leashing.' ].
 system_message(leash([A|B])) -->
diff --git a/pl/modules.yap b/pl/modules.yap
index 2124f5e3e..c7c335257 100644
--- a/pl/modules.yap
+++ b/pl/modules.yap
@@ -142,18 +142,24 @@ module(N) :-
 	'$use_preds'(P,Publics,Mod,M),
 	'$use_preds'(Ps,Publics,Mod,M).
 '$use_preds'(N/K,Publics,M,Mod) :-
-    (  lists:memberchk(N/K,Publics) -> true ;
-	print_message(warning,import(N/K,Mod,M,private))
-    ),
-    '$do_import'(N, K, M, Mod).
-'$use_preds'(N//K0,Publics,M,Mod) :-
-	K is K0+2,
-	(  lists:memberchk(N/K,Publics) -> true ;
+          (  lists:memberchk(N/K,Publics) -> true ;
 	   print_message(warning,import(N/K,Mod,M,private))
-	),
-	'$do_import'(N, K, M, Mod).
+          ),
+          '$do_import'(N, K, M, Mod).
+'$use_preds'(N//K0,Publics,M,Mod) :-
+	  K is K0+2,
+	  (  lists:memberchk(N/K,Publics) -> true ;
+	     print_message(warning,import(N/K,Mod,M,private))
+	  ),
+	  '$do_import'(N, K, M, Mod).
  
 
+%
+% ignore imports that we  do export
+%
+'$do_import'(N, K, M, T) :-
+	recorded('$module','$module'(_F,T,MyExports),_),
+	lists:member(N/K,MyExports), !.
 '$do_import'(N, K, M, T) :-
 	functor(G,N,K),
 	'$follow_import_chain'(M,G,M0,G0),
@@ -169,16 +175,16 @@ module(N) :-
 	).
 
 '$follow_import_chain'(M,G,M0,G0) :-
-	recorded('$import','$import'(M1,M,G1,G,_,_),_), !,
+	recorded('$import','$import'(M1,M,G1,G,_,_),_), M \= M1, !,
 	'$follow_import_chain'(M1,G1,M0,G0).
 '$follow_import_chain'(M,G,M,G).
 
 '$check_import'(M,T,N,K) :-
-   recorded('$import','$import'(MI,T,_,_,N,K),R),
-    \+ '$module_produced by'(M,T,N,K), !,
-    format(user_error,"NAME CLASH: ~w was already imported to module ~w;~n",[MI:N/K,T]),
-    format(user_error,"            Do you want to import it from ~w ? [y or n] ",M),
-    repeat,
+	recorded('$import','$import'(MI,T,_,_,N,K),R),
+	\+ '$module_produced by'(M,T,N,K), !,
+	format(user_error,"NAME CLASH: ~w was already imported to module ~w;~n",[MI:N/K,T]),
+	format(user_error,"            Do you want to import it from ~w ? [y or n] ",M),
+	repeat,
 	get0(C), '$skipeol'(C),
 	( C is "y" -> erase(R), !;
 	  C is "n" -> !, fail;