ENHANCED: call_nth(Goal, 0) now fails, correct error for N < 0.

This addresses #1307.
2022-03-07 23:38:30 +01:00
parent bd594e0c05
commit 69e52d1ed8
1 changed files with 5 additions and 2 deletions
--- a/src/lib/iso_ext.pl
+++ b/src/lib/iso_ext.pl
@@ -203,8 +203,11 @@ partial_string_tail(String, Tail) :-

 call_nth(Goal, N) :-
    can_be(integer, N),
-    (   integer(N), N =< 0,
-        domain_error(positive_integer, N, call_nth/2)
+    (   integer(N) ->
+        (   N < 0 ->
+            domain_error(not_less_than_zero, N, call_nth/2)
+        ;   N > 0
+        )
    ;   true
    ),
    setup_call_cleanup(call_nth_nesting(ID),