diff --git a/Cargo.toml b/Cargo.toml
index 438ac82..a0dfdff 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,6 +3,11 @@ name = "lilac"
 version = "0.0.1"
 edition = "2021"
 
+[features]
+default = ["pest"]
+pest = ["dep:pest", "dep:pest_derive"]
+tree-sitter = ["dep:tree-sitter", "dep:tree-sitter-lila"]
+
 [dependencies]
 clap = { version = "4.5.7", features = ["derive"] }
 cranelift = "0.109.0"
@@ -10,10 +15,19 @@ cranelift-jit = "0.109.0"
 cranelift-module = "0.109.0"
 cranelift-native = "0.109.0"
 lazy_static = "1.4.0"
-pest = "2.7.4"
-pest_derive = "2.7.4"
+pest = { version = "2.7.4", optional = true }
+pest_derive = { version = "2.7.4", optional = true }
+tree-sitter = { version = "0.22", optional = true }
 ariadne = "0.4.1"
 anyhow = "1.0.86"
 
+[dependencies.tree-sitter-lila]
+version = "0.0.1"
+optional = true
+path = "./tree-sitter-lila"
+
 [dev-dependencies]
 pretty_assertions = "1.4.0"
+
+[build-dependencies]
+cc = "*"
diff --git a/src/parsing/backend/mod.rs b/src/parsing/backend/mod.rs
index b63ce4a..551f911 100644
--- a/src/parsing/backend/mod.rs
+++ b/src/parsing/backend/mod.rs
@@ -1 +1,5 @@
+#[cfg(feature = "pest")]
 pub mod pest;
+
+#[cfg(feature = "tree-sitter")]
+pub mod tree_sitter;
diff --git a/src/parsing/backend/pest/mod.rs b/src/parsing/backend/pest/mod.rs
index 82ba471..3dd58fa 100644
--- a/src/parsing/backend/pest/mod.rs
+++ b/src/parsing/backend/pest/mod.rs
@@ -1,6 +1,3 @@
-use std::fs;
-use std::path::Path;
-
 use expr::BinaryExpression;
 use pest::iterators::Pair;
 use pest::pratt_parser::PrattParser;
@@ -38,14 +35,6 @@ pub struct Parser {
 }
 
 impl crate::parsing::Parser for Parser {
-    fn parse_file(&mut self, path: &Path, id: SourceId) -> anyhow::Result<Module> {
-        let source = fs::read_to_string(path)?;
-        let module_path = ModulePath::from(path);
-        let mut module = self.parse_as_module(&source, module_path, id)?;
-        module.file = Some(path.to_owned());
-        Ok(module)
-    }
-
     fn parse_as_module(
         &mut self,
         source: &str,
diff --git a/src/parsing/backend/tree_sitter/lib.rs b/src/parsing/backend/tree_sitter/lib.rs
deleted file mode 100644
index 775fdf2..0000000
--- a/src/parsing/backend/tree_sitter/lib.rs
+++ /dev/null
@@ -1,222 +0,0 @@
-use tree_sitter::{self, Language, Parser, TreeCursor};
-
-enum Ast {
-    FuncDef(FuncDef),
-    Expr(Expr),
-    Module(Vec<Ast>),
-    Block(Vec<Statement>, Option<Expr>),
-    Statement(Statement),
-}
-
-enum BinaryOperator {
-    Add,
-    Sub,
-    Mul,
-    Div,
-}
-
-enum Expr {
-    BinaryExpression(Box<Expr>, BinaryOperator, Box<Expr>),
-}
-
-enum Statement {
-    AssignStatement(Identifier, Expr),
-}
-
-type Identifier = String;
-type Type = String;
-
-struct Parameter {
-    name: Identifier,
-    typ: Type,
-}
-
-struct FuncDef {
-    name: Identifier,
-    parameters: Vec<Parameter>,
-    return_type: Option<Type>,
-    body: Box<Ast>,
-}
-
-#[derive(Debug)]
-struct AstError {
-    message: String,
-}
-
-impl AstError {
-    fn new(message: &str) -> Self {
-        AstError {
-            message: message.into(),
-        }
-    }
-}
-
-extern "C" {
-    fn tree_sitter_krone() -> Language;
-}
-
-struct TreeCursorChildrenIter<'a, A: AsRef<[u8]>> {
-    source: A,
-    cursor: &'a mut TreeCursor<'a>,
-    on_child: bool,
-}
-
-impl<'a, A: AsRef<[u8]>> Iterator for TreeCursorChildrenIter<'a, A> {
-    type Item = Result<Ast, AstError>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        if self.on_child {
-            if self.cursor.goto_next_sibling() {
-                Some(parse_from_cursor(&self.source, self.cursor))
-            } else {
-                self.cursor.goto_parent();
-                None
-            }
-        } else {
-            if self.cursor.goto_first_child() {
-                self.on_child = true;
-                Some(parse_from_cursor(&self.source, self.cursor))
-            } else {
-                None
-            }
-        }
-    }
-}
-
-fn iter_children<'a, A: AsRef<[u8]>>(
-    source: A,
-    cursor: &'a mut TreeCursor<'a>,
-) -> TreeCursorChildrenIter<'a, A> {
-    TreeCursorChildrenIter {
-        source,
-        cursor,
-        on_child: false,
-    }
-}
-
-fn parse_from_cursor<'a>(
-    source: impl AsRef<[u8]>,
-    cursor: &'a mut TreeCursor<'a>,
-) -> Result<Ast, AstError> {
-    match cursor.node().kind() {
-        "block" => {
-            let mut statements = Vec::new();
-            let mut value = None;
-
-            for child in iter_children(source, cursor) {
-                match child.unwrap() {
-                    Ast::Statement(statement) => {
-                        if value.is_none() {
-                            statements.push(statement);
-                        } else {
-                            return Err(AstError::new(
-                                "cannot have a statement after an expression in a block",
-                            ));
-                            // perhaps there is a missing semicolon ;
-                        }
-                    }
-                    Ast::Expr(expr) => value = Some(expr),
-                    _ => return Err(AstError::new("invalid node type")),
-                };
-            }
-
-            let block = Ast::Block(statements, value);
-            Ok(block)
-        }
-
-        "function_definition" => {
-            // 1: name
-            assert!(cursor.goto_first_child());
-            assert!(cursor.field_name() == Some("name"));
-            let name: String = cursor
-                .node()
-                .utf8_text(source.as_ref())
-                .expect("utf8 error")
-                .into();
-
-            // 2: parameters
-            assert!(cursor.goto_next_sibling());
-            assert!(cursor.field_name() == Some("parameters"));
-            let mut parameters = Vec::new();
-
-            if cursor.goto_first_child() {
-                loop {
-                    let param = cursor.node();
-
-                    assert!(cursor.goto_first_child());
-                    let name = cursor
-                        .node()
-                        .utf8_text(source.as_ref())
-                        .expect("utf8 error")
-                        .into();
-
-                    assert!(cursor.goto_next_sibling());
-                    let typ = cursor
-                        .node()
-                        .utf8_text(source.as_ref())
-                        .expect("utf8 error")
-                        .into();
-
-                    cursor.goto_parent();
-
-                    parameters.push(Parameter { name, typ });
-
-                    if !cursor.goto_next_sibling() {
-                        break;
-                    }
-                }
-
-                cursor.goto_parent();
-            }
-
-            // 3: return type
-            assert!(cursor.goto_next_sibling());
-            assert!(cursor.field_name() == Some("return_type"));
-            let return_type = Some(
-                cursor
-                    .node()
-                    .utf8_text(source.as_ref())
-                    .expect("utf8 error")
-                    .into(),
-            );
-
-            // 4: body
-            assert!(cursor.goto_next_sibling());
-            assert!(cursor.field_name() == Some("body"));
-            let body = parse_from_cursor(source, cursor).unwrap();
-            let body = Box::new(body);
-
-            Ok(Ast::FuncDef(FuncDef {
-                name,
-                parameters,
-                return_type,
-                body,
-            }))
-        }
-
-        _ => panic!("unexpected node kind: {}", cursor.node().kind()),
-    }
-}
-
-fn parse_with_tree_sitter(source: impl AsRef<[u8]>) -> Result<Ast, AstError> {
-    let mut parser = Parser::new();
-    let language = unsafe { tree_sitter_krone() };
-    parser.set_language(language).unwrap();
-
-    let tree = parser.parse(&source, None).unwrap();
-
-    let mut cursor = tree.walk();
-    let node = cursor.node();
-    assert!(node.kind() == "source_file");
-    let mut top_level_nodes = Vec::new();
-
-    for node in iter_children(source, &mut cursor) {
-        let node = node.unwrap();
-        match node {
-            Ast::FuncDef(_) => top_level_nodes.push(node),
-            _ => panic!("unexpected top-level node type"),
-        };
-    }
-
-    Ok(Ast::Module(top_level_nodes))
-}
diff --git a/src/parsing/backend/tree_sitter/mod.rs b/src/parsing/backend/tree_sitter/mod.rs
new file mode 100644
index 0000000..2acf031
--- /dev/null
+++ b/src/parsing/backend/tree_sitter/mod.rs
@@ -0,0 +1,203 @@
+use anyhow::{anyhow, bail, ensure};
+use tree_sitter::{Node, TreeCursor};
+
+use crate::ast::*;
+
+pub struct Parser(tree_sitter::Parser);
+
+impl Default for Parser {
+    fn default() -> Self {
+        let mut parser = tree_sitter::Parser::new();
+        let language = tree_sitter_lila::language();
+        parser.set_language(&language).unwrap();
+
+        Self(parser)
+    }
+}
+
+struct SourceParsingContext<'a> {
+    source: &'a str,
+    source_id: SourceId,
+    cursor: &'a mut TreeCursor<'a>,
+}
+
+impl<'a> SourceParsingContext<'a> {
+    fn span(&self) -> Span {
+        Span {
+            source: self.source_id,
+            start: self.cursor.node().start_byte(),
+            end: self.cursor.node().end_byte(),
+        }
+    }
+
+    fn iter_children(&'a mut self) -> NodeIterator<'a> {
+        NodeIterator {
+            is_child: false,
+            cursor: self.cursor,
+        }
+    }
+}
+
+struct NodeIterator<'a> {
+    is_child: bool,
+    cursor: &'a mut TreeCursor<'a>,
+}
+
+impl<'a> Iterator for NodeIterator<'a> {
+    type Item = Node<'a>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.is_child {
+            match self.cursor.goto_next_sibling() {
+                true => Some(self.cursor.node()),
+                false => None,
+            }
+        } else {
+            match self.cursor.goto_first_child() {
+                true => Some(self.cursor.node()),
+                false => None,
+            }
+        }
+    }
+}
+
+impl Parser {
+    fn parse_param<'a>(&self, ctx: &mut SourceParsingContext) -> anyhow::Result<Parameter> {
+        ensure!(ctx.cursor.goto_first_child());
+        let name = ctx
+            .cursor
+            .node()
+            .utf8_text(ctx.source.as_ref())
+            .expect("utf8 error")
+            .into();
+
+        ensure!(ctx.cursor.goto_next_sibling());
+        let typ = ctx
+            .cursor
+            .node()
+            .utf8_text(ctx.source.as_ref())
+            .expect("utf8 error")
+            .into();
+
+        ctx.cursor.goto_parent();
+
+        Ok(Parameter { name, typ })
+    }
+
+    fn parse_function<'a>(
+        &self,
+        ctx: &mut SourceParsingContext,
+    ) -> anyhow::Result<FunctionDefinition> {
+        let span = ctx.span();
+
+        // 1: name
+        assert!(ctx.cursor.goto_first_child());
+        assert!(ctx.cursor.field_name() == Some("name"));
+        let name: String = ctx
+            .cursor
+            .node()
+            .utf8_text(ctx.source.as_ref())
+            .expect("utf8 error")
+            .into();
+
+        // 2: parameters
+        assert!(ctx.cursor.goto_next_sibling());
+        assert!(ctx.cursor.field_name() == Some("parameters"));
+        let mut parameters = Vec::new();
+
+        if ctx.cursor.goto_first_child() {
+            loop {
+                let param = self.parse_param(ctx)?;
+
+                parameters.push(param);
+
+                if !ctx.cursor.goto_next_sibling() {
+                    break;
+                }
+            }
+
+            ctx.cursor.goto_parent();
+        }
+
+        // 3: return type
+        assert!(ctx.cursor.goto_next_sibling());
+        assert!(ctx.cursor.field_name() == Some("return_type"));
+        let return_type = Some(ctx.cursor.node().utf8_text(ctx.source.as_ref())?.into());
+        let return_type_span = Some(ctx.span());
+
+        // 4: body
+        assert!(ctx.cursor.goto_next_sibling());
+        assert!(ctx.cursor.field_name() == Some("body"));
+        let body = Box::new(self.parse_block(ctx)?);
+
+        Ok(FunctionDefinition {
+            name,
+            parameters,
+            return_type,
+            return_type_span,
+            body,
+            span,
+        })
+    }
+
+    fn parse_block(&self, ctx: &mut SourceParsingContext) -> anyhow::Result<Block> {
+        let mut statements = Vec::new();
+        let mut value = None;
+
+        for child in ctx.iter_children() {
+            match child.kind() {
+                "statement" => {
+                    ensure!(
+                        value.is_none(),
+                        "cannot have a statement after an expression in a block"
+                    );
+                    let statement = self.parse_statement(ctx)?;
+                    statements.push(statement);
+                }
+                "expr" => value = Some(self.parse_expr(ctx)),
+            };
+        }
+
+        let block = Block { statements, value };
+        Ok(block)
+    }
+
+    fn parse_statement(&self, ctx: &mut SourceParsingContext) -> anyhow::Result<Statement> {
+        assert_eq!(ctx.cursor.node().kind(), "statement");
+
+        ctx.cursor.Some(statement)
+    }
+
+    fn parse_expr(&self, ctx: &mut SourceParsingContext) -> anyhow::Result<Expr> {
+        assert_eq!(ctx.cursor.node().kind(), "expr");
+
+        Some()
+    }
+}
+
+impl crate::parsing::Parser for Parser {
+    fn parse_as_module(
+        &mut self,
+        source: &str,
+        path: ModulePath,
+        id: SourceId,
+    ) -> anyhow::Result<Module> {
+        let tree = self.0.parse(&source, None).unwrap();
+
+        let mut cursor = tree.walk();
+        {
+            let node = cursor.node();
+            assert!(node.kind() == "source_file");
+        }
+
+        let ctx = SourceParsingContext {
+            source,
+            source_id: id,
+            cursor: &mut cursor,
+        };
+
+        let mut module = Module::new(path);
+
+        Ok(module)
+    }
+}
diff --git a/src/parsing/mod.rs b/src/parsing/mod.rs
index 8cf64e4..5984bfd 100644
--- a/src/parsing/mod.rs
+++ b/src/parsing/mod.rs
@@ -4,7 +4,13 @@ mod tests;
 use crate::ast::{Module, ModulePath, SourceId};
 
 pub trait Parser: Default {
-    fn parse_file(&mut self, path: &std::path::Path, id: SourceId) -> anyhow::Result<Module>;
+    fn parse_file(&mut self, path: &std::path::Path, id: SourceId) -> anyhow::Result<Module> {
+        let source = std::fs::read_to_string(path)?;
+        let module_path = ModulePath::from(path);
+        let mut module = self.parse_as_module(&source, module_path, id)?;
+        module.file = Some(path.to_owned());
+        Ok(module)
+    }
 
     fn parse_as_module(
         &mut self,
@@ -14,5 +20,8 @@ pub trait Parser: Default {
     ) -> anyhow::Result<Module>;
 }
 
-pub use self::backend::pest::Parser as PestParser;
-pub use PestParser as DefaultParser;
+#[cfg(feature = "pest")]
+pub use self::backend::pest::Parser as DefaultParser;
+
+#[cfg(feature = "tree-sitter")]
+pub use self::backend::tree_sitter::Parser as DefaultParser;
diff --git a/tree-sitter-lila b/tree-sitter-lila
index ef98449..a44288e 160000
--- a/tree-sitter-lila
+++ b/tree-sitter-lila
@@ -1 +1 @@
-Subproject commit ef984491f7d650f910f65605bd07ad3bf34484b9
+Subproject commit a44288effcf367d693d02608cf8528fdef89c080