Merge pull request mthom#2275 from triska/master

Prevent assertion of clauses for (-->)/2 when DCGs are enabled.
triska · Jan 5, 2024 · ed92e1b · ed92e1b
2 parents d51defe + f2b63d1
commit ed92e1b
Showing 1 changed file with 9 additions and 1 deletion.
diff --git a/src/lib/dcgs.pl b/src/lib/dcgs.pl
@@ -14,7 +14,8 @@
            phrase/3,
            seq//1,
            seqq//1,
-           ... //0
+           ... //0,
+           (-->)/2
           ]).
 
 :- use_module(library(error)).
@@ -220,3 +221,10 @@
     ).
 
 user:goal_expansion(phrase(GRBody, S), phrase(GRBody, S, [])).
+
+
+% (-->)/2 behaves as if it didn't exist. We export (and define) it
+% only so that clauses for (-->)/2 cannot be asserted when
+% library(dcgs) is loaded.
+
+(_-->_) :- throw(error(existence_error(procedure,(-->)/2),(-->)/2)).