Changeset 4216 for trunk/library/set1.lgt

Timestamp:

04/22/08 08:09:59 (4 months ago)

Author:

pmoura

Message:

Updated the definitions of the predicate valid/1 for the library objects "list", "list(Type)", "numberlist", "set", "set(Type)", "varlist" to fail for lists with unbound tails after discussion with Jan Wielemaker and Ulrich Neumerkel.

Files:

• trunk/library/set1.lgt (modified) (1 diff)

trunk/library/set1.lgt

@@ -4 +4 @@
 
     :- info([
-        version is 1.01,
+        version is 1.1,
         author is 'Paulo Moura',
-        date is 2006/4/25,
+        date is 2008/4/22,
         comment is 'Set predicates with elements constrained to a single type.']).
 
-    valid(Set) :-
-        nonvar(Set),
+    valid(-) :-             % catch variables
+        !,
+        fail.
+    valid([]) :-
+        !.
+    valid([Element| Set]) :-
+        check_order(Set, Element).
+
+    check_order(-, _) :-    % catch unbound tails
+        !,
+        fail.
+    check_order([], _) :-
+        !.
+    check_order([Element2| Set], Element1) :-
         parameter(1, Type),
-        \+ \+ valid(Set, Type).
-
-    valid([], _) :-
-        !.
-    valid([Element], Type) :-
-        !,
-        Type::valid(Element).
-    valid([Element1, Element2| Set], Type) :-
-        Element1 @< Element2,
         Type::valid(Element1),
         Type::valid(Element2),
-        valid([Element2| Set], Type).
+        Element2 @> Element1,
+        check_order(Set, Element2).
 
 :- end_object.