From 1146fe99d7d1ed955fbdc48d358b5fae9f15130c Mon Sep 17 00:00:00 2001
From: Jeremy Wall <jeremy@marzhillstudios.com>
Date: Mon, 16 Apr 2018 20:05:08 -0500
Subject: [PATCH] Add a walker for ASTs

---
 src/ast/mod.rs  |  1 +
 src/ast/walk.rs | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+)
 create mode 100644 src/ast/walk.rs

diff --git a/src/ast/mod.rs b/src/ast/mod.rs
index 2710913..97e0623 100644
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -16,3 +16,4 @@
 
 #[macro_use]
 pub mod tree;
+pub mod walk;
diff --git a/src/ast/walk.rs b/src/ast/walk.rs
new file mode 100644
index 0000000..b89a865
--- /dev/null
+++ b/src/ast/walk.rs
@@ -0,0 +1,22 @@
+// Copyright 2018 Jeremy Wall <jeremy@marzhillstudios.com>
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+use std::error;
+
+use ast::tree;
+
+pub trait Visit {
+    fn stmt(&self, stmt: &tree::Statement) -> Result<(), Box<error::Error>>;
+    fn expr(&self, expr: &tree::Expression) -> Result<(), Box<error::Error>>;
+    fn val(&self, expr: &tree::Value) -> Result<(), Box<error::Error>>;
+}