diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index 081fe7a..fcfb34e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ Cargo.lock
 .vscode
 .gdb_history
 perf.data*
+.direnv
\ No newline at end of file
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..d45da12
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,224 @@
+{
+  "nodes": {
+    "fenix": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "rust-analyzer-src": "rust-analyzer-src"
+      },
+      "locked": {
+        "lastModified": 1774942139,
+        "narHash": "sha256-Wib0RDVsptJWQd2ldBgFpMF0kRjQKHejQq9an+ActYo=",
+        "owner": "nix-community",
+        "repo": "fenix",
+        "rev": "0beafd2252f80385610e2f12cbecfdb9d2dfb0a0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "fenix",
+        "type": "github"
+      }
+    },
+    "fenix_2": {
+      "inputs": {
+        "nixpkgs": [
+          "naersk",
+          "nixpkgs"
+        ],
+        "rust-analyzer-src": "rust-analyzer-src_2"
+      },
+      "locked": {
+        "lastModified": 1752475459,
+        "narHash": "sha256-z6QEu4ZFuHiqdOPbYss4/Q8B0BFhacR8ts6jO/F/aOU=",
+        "owner": "nix-community",
+        "repo": "fenix",
+        "rev": "bf0d6f70f4c9a9cf8845f992105652173f4b617f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "fenix",
+        "type": "github"
+      }
+    },
+    "naersk": {
+      "inputs": {
+        "fenix": "fenix_2",
+        "nixpkgs": "nixpkgs_2"
+      },
+      "locked": {
+        "lastModified": 1769799857,
+        "narHash": "sha256-88IFXZ7Sa1vxbz5pty0Io5qEaMQMMUPMonLa3Ls/ss4=",
+        "owner": "nix-community",
+        "repo": "naersk",
+        "rev": "9d4ed44d8b8cecdceb1d6fd76e74123d90ae6339",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "naersk",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1774709303,
+        "narHash": "sha256-D3Q07BbIA2KnTcSXIqqu9P586uWxN74zNoCH3h2ESHg=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "8110df5ad7abf5d4c0f6fb0f8f978390e77f9685",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1752077645,
+        "narHash": "sha256-HM791ZQtXV93xtCY+ZxG1REzhQenSQO020cu6rHtAPk=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "be9e214982e20b8310878ac2baa063a961c1bdf6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_3": {
+      "locked": {
+        "lastModified": 1774855581,
+        "narHash": "sha256-YkreHeMgTCYvJ5fESV0YyqQK49bHGe2B51tH6claUh4=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "15c6719d8c604779cf59e03c245ea61d3d7ab69b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_4": {
+      "locked": {
+        "lastModified": 1744536153,
+        "narHash": "sha256-awS2zRgF4uTwrOKwwiJcByDzDOdo3Q1rPZbiHQg/N38=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "18dd725c29603f582cf1900e0d25f9f1063dbf11",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "fenix": "fenix",
+        "naersk": "naersk",
+        "nixpkgs": "nixpkgs_3",
+        "rust-overlay": "rust-overlay",
+        "utils": "utils"
+      }
+    },
+    "rust-analyzer-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1774903498,
+        "narHash": "sha256-iJUfApxI0eq6GL6NaVmMn7xf6GVNb9w6BF0d4Hy7TKU=",
+        "owner": "rust-lang",
+        "repo": "rust-analyzer",
+        "rev": "a75b500a010062cd2589be6a4b76f84f6a816943",
+        "type": "github"
+      },
+      "original": {
+        "owner": "rust-lang",
+        "ref": "nightly",
+        "repo": "rust-analyzer",
+        "type": "github"
+      }
+    },
+    "rust-analyzer-src_2": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1752428706,
+        "narHash": "sha256-EJcdxw3aXfP8Ex1Nm3s0awyH9egQvB2Gu+QEnJn2Sfg=",
+        "owner": "rust-lang",
+        "repo": "rust-analyzer",
+        "rev": "591e3b7624be97e4443ea7b5542c191311aa141d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "rust-lang",
+        "ref": "nightly",
+        "repo": "rust-analyzer",
+        "type": "github"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": "nixpkgs_4"
+      },
+      "locked": {
+        "lastModified": 1774926780,
+        "narHash": "sha256-JMdDYn0F+swYBILlpCeHDbCSyzqkeSGNxZ/Q5J584jM=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "962a0934d0e32f42d1b5e49186f9595f9b178d2d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..028f153
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,46 @@
+{
+  inputs = {
+    naersk.url = "github:nix-community/naersk";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    utils.url = "github:numtide/flake-utils";
+    fenix.url = "github:nix-community/fenix";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+  };
+
+  outputs = inputs:
+    with inputs;
+    utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+        naersk-lib = pkgs.callPackage naersk { };
+        nbi = with pkgs; [
+
+          (rust-bin.selectLatestNightlyWith (toolchain: toolchain.default.override {
+            extensions = [ "rust-src" "rust-analyzer" "clippy" ];
+          }))
+          cargo-nextest
+          cargo-criterion
+          pkg-config
+          sccache
+        ];
+
+        bi = with pkgs; [
+          just
+          cargo-watch
+          samply
+        ];
+      in
+      {
+        defaultPackage = naersk-lib.buildPackage ./.;
+        devShell = with pkgs; mkShell {
+          nativeBuildInputs = nbi;
+          buildInputs = bi;
+
+          RUST_SRC_PATH = rustPlatform.rustLibSrc;
+        };
+      }
+    );
+}
diff --git a/src/syntax/element.rs b/src/syntax/element.rs
index aa4b88a..34f1dc6 100644
--- a/src/syntax/element.rs
+++ b/src/syntax/element.rs
@@ -29,7 +29,7 @@ use super::{
     tracing::instrument(level = "debug", skip(input), fields(input = input.s))
 )]
 pub fn element_nodes(input: Input) -> Result<Vec<GreenElement>, nom::Err<()>> {
-    debug_assert!(!input.is_empty());
+    // debug_assert!(!input.is_empty());
     // TODO:
     // debug_assert!(
     //     blank_lines(input).unwrap().1.is_empty(),
@@ -178,7 +178,7 @@ fn positions() {
 #[test]
 fn parse() {
     use crate::syntax::{SyntaxKind, SyntaxNode};
-    use crate::{syntax::combinator::node, ParseConfig};
+    use crate::{ParseConfig, syntax::combinator::node};
 
     let t = |input: &str| {
         let config = &ParseConfig::default();
@@ -220,7 +220,7 @@ b"#),
 #[test]
 fn affiliated_keywords() {
     use crate::syntax::{SyntaxKind, SyntaxNode};
-    use crate::{syntax::combinator::node, ParseConfig};
+    use crate::{ParseConfig, syntax::combinator::node};
 
     let t = |input: &str| {
         let config = &ParseConfig::default();