From 52f019c9ba5b080b0a3da1fcf5c0512cc9971e41 Mon Sep 17 00:00:00 2001
From: Wilfred Hughes <me@wilfred.me.uk>
Date: Sat, 28 Aug 2021 11:39:40 -0700
Subject: [PATCH] Write a printing tree walker for displaying tree-sitter
 results

---
 src/main.rs               |  2 +-
 src/tree_sitter_parser.rs | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 39c6052b7..4611559a3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -147,7 +147,7 @@ fn main() {
                     let bytes = read_or_die(&path);
                     let src = String::from_utf8_lossy(&bytes).to_string();
                     let tree = tsp::parse_to_tree(&src, &ts_lang);
-                    println!("{:#?}", tree.root_node());
+                    tsp::print_tree(tree);
                 }
                 None => {
                     println!("No tree-sitter parser for extension: {:?}", extension);
diff --git a/src/tree_sitter_parser.rs b/src/tree_sitter_parser.rs
index c6ecd8778..7606e60bc 100644
--- a/src/tree_sitter_parser.rs
+++ b/src/tree_sitter_parser.rs
@@ -112,6 +112,27 @@ pub fn parse_to_tree(src: &str, config: &TreeSitterConfig) -> tree_sitter::Tree
     parser.parse(src, None).unwrap()
 }
 
+pub fn print_tree(tree: tree_sitter::Tree) {
+    let mut cursor = tree.walk();
+    print_cursor(&mut cursor, 0);
+}
+
+fn print_cursor(cursor: &mut TreeCursor, depth: usize) {
+    loop {
+        let node = cursor.node();
+        println!("{}{:#?}", "  ".repeat(depth), node);
+
+        if cursor.goto_first_child() {
+            print_cursor(cursor, depth + 1);
+            cursor.goto_parent();
+        }
+
+        if !cursor.goto_next_sibling() {
+            break;
+        }
+    }
+}
+
 /// Parse `src` with tree-sitter and convert to difftastic Syntax.
 pub fn parse<'a>(
     arena: &'a Arena<Syntax<'a>>,