1 files changed, 18 insertions, 0 deletions
diff --git a/builtins.c b/builtins.c
index a037a23..e403541 100644
--- a/builtins.c
+++ b/builtins.c
@@ -229,6 +229,21 @@ canbecalled(Term *t)
 		return 1;
 }
 
+void
+updateclausenr(Term *t, uvlong nr)
+{
+	/* Change the clause number on the term and its subterms, unless it is a variable */
+	if(t->tag == VariableTerm)
+		return;
+
+	t->clausenr = nr;
+	if(t->tag == CompoundTerm){
+		Term *child;
+		for(child = t->children; child != nil; child = child->next)
+			updateclausenr(child, nr);
+	}
+}
+
 int
 builtincall(Term *goal, Binding **bindings, Module *module)
 {
@@ -238,6 +253,9 @@ builtincall(Term *goal, Binding **bindings, Module *module)
 	if(!canbecalled(callgoal))
 		Throw(typeerror(L"callable", callgoal));
 
+	updateclausenr(callgoal, clausenr);
+	clausenr++;
+
 	goalstack = addgoals(goalstack, callgoal, module);
 	return 1;
 }