add error value to occurs_check prolog flag (#783)

2021-02-28 11:44:07 -07:00
parent 81ecd17b93
commit 101ed9a633
6 changed files with 65 additions and 12 deletions
--- a/src/lib/builtins.pl
+++ b/src/lib/builtins.pl
@@ -171,6 +171,8 @@ set_prolog_flag(occurs_check, true) :-
    !, '$set_sto_as_unify'.
 set_prolog_flag(occurs_check, false) :-
    !, '$set_nsto_as_unify'.
+set_prolog_flag(occurs_check, error) :-
+    !, '$set_sto_with_error_as_unify'.
 set_prolog_flag(double_quotes, Value) :-
    throw(error(domain_error(flag_value, double_quotes + Value),
 		        set_prolog_flag/2)). % 8.17.1.3 e