Expr's functions now support parameters with default value

term.go

@@ -229,3 +229,12 @@ func (self *term) evalPrefix(ctx ExprContext) (childValue any, err error) {
 	}
 	return
 }
+
+// NOTE Temporary solution to support function parameters with default value
+
+func (self *term) forceChild(c *term) {
+	if self.children == nil {
+		self.children = make([]*term, 0, 1)
+	}
+	self.children = append(self.children, c)
+}