the function call procedure now check the number of actual parameters against the numer of formal parameters

operator-assign.go

@@ -29,7 +29,14 @@ func evalAssign(ctx ExprContext, self *term) (v any, err error) {
 
 	if v, err = self.children[1].compute(ctx); err == nil {
 		if functor, ok := v.(Functor); ok {
-			ctx.RegisterFunc(leftTerm.source(), functor, 0, -1)
+			var minArgs, maxArgs int = 0, 0
+
+			if funcDef, ok := functor.(*funcDefFunctor); ok {
+				l := len(funcDef.params)
+				minArgs = l
+				maxArgs = l
+			}
+			ctx.RegisterFunc(leftTerm.source(), functor, minArgs, maxArgs)
 		} else {
 			ctx.setVar(leftTerm.source(), v)
 		}