begin tree-sitter parsing backend

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 = "*"