feature: tree-sitter like traverse API

crates/postgresql-cst-parser/examples/tree_sitter_like.rs

@@ -0,0 +1,49 @@
+use postgresql_cst_parser::{
+    parse,
+    tree_sitter::{as_tree_sitter_cursor, get_ts_tree_and_range_map, TreeCursor},
+};
+
+fn main() {
+    let src = r#"
+-- comment
+SELECT
+	1 as X
+,	2 -- comment
+,	3
+FROM
+	A
+,	B
+;
+select
+    1
+,   2
+;
+
+"#;
+
+    let node = parse(&src).unwrap();
+    let (node, range_map) = get_ts_tree_and_range_map(&src, &node);
+    let mut cursor = as_tree_sitter_cursor(src, &node, range_map);
+
+    visit(&mut cursor, 0, &src);
+}
+
+const UNIT: usize = 2;
+fn visit(cursor: &mut TreeCursor, depth: usize, src: &str) {
+    (0..(depth * UNIT)).for_each(|_| print!("-"));
+
+    print!("{}", cursor.node().kind());
+
+    if cursor.node().child_count() == 0 {
+        print!(" \"{}\"", cursor.node().text().escape_debug());
+    }
+    println!(" {}", cursor.node().range());
+
+    if cursor.goto_first_child() {
+        visit(cursor, depth + 1, src);
+        while cursor.goto_next_sibling() {
+            visit(cursor, depth + 1, src);
+        }
+        cursor.goto_parent();
+    }
+}