Start migrating to tree sitter

Migrates all the lower level code to tree-sitter not touching passes yet.

src/tree_sitter.rs

@@ -0,0 +1,34 @@
+use anyhow::{Context, Result};
+
+pub fn parse(source: &str) -> Result<tree_sitter::Tree> {
+    let mut parser = tree_sitter::Parser::new();
+    parser
+        .set_language(tree_sitter_rust::language())
+        .context("loading tree sitter rust grammar")?;
+    let content_ts = parser.parse(source, None).context("parsing file")?;
+    Ok(content_ts)
+}
+
+pub fn format(file: tree_sitter::Tree, source: &str) -> anyhow::Result<String> {
+    let mut s = Vec::new();
+    tree_sitter_edit::render(&mut s, &file, source.as_bytes(), &Editor);
+
+    Ok(String::from_utf8(s).unwrap())
+}
+
+struct Editor;
+
+impl tree_sitter_edit::Editor for Editor {
+    fn has_edit(&self, tree: &tree_sitter::Tree, node: &tree_sitter::Node<'_>) -> bool {
+        false
+    }
+
+    fn edit(
+        &self,
+        source: &[u8],
+        tree: &tree_sitter::Tree,
+        node: &tree_sitter::Node<'_>,
+    ) -> Vec<u8> {
+        unimplemented!()
+    }
+}