From 4196d9c290688b7b02870f0e94129bf775b83903 Mon Sep 17 00:00:00 2001
From: Akira Komamura <akira.komamura@gmail.com>
Date: Sun, 8 Oct 2023 19:02:39 +0900
Subject: [PATCH] rust: Add treefmt-nix

---
 rust/flake.nix   | 14 ++++++++++++++
 rust/treefmt.nix |  6 ++++++
 2 files changed, 20 insertions(+)
 create mode 100644 rust/treefmt.nix

diff --git a/rust/flake.nix b/rust/flake.nix
index 827fd7d..32ed907 100644
--- a/rust/flake.nix
+++ b/rust/flake.nix
@@ -2,11 +2,17 @@
   inputs = {
     rust-overlay.url = "github:oxalica/rust-overlay";
     systems.url = "github:nix-systems/default";
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.url = "nixpkgs";
+    };
   };
 
   outputs = {
+    self,
     systems,
     nixpkgs,
+    treefmt-nix,
     ...
   } @ inputs: let
     eachSystem = f:
@@ -17,6 +23,8 @@
             overlays = [inputs.rust-overlay.overlays.default];
           })
       );
+
+    treefmtEval = eachSystem (pkgs: treefmt-nix.lib.evalModule pkgs ./treefmt.nix);
   in {
     devShells = eachSystem (pkgs: {
       default = pkgs.mkShell {
@@ -28,5 +36,11 @@
         ];
       };
     });
+
+    formatter = eachSystem (pkgs: treefmtEval.${pkgs.system}.config.build.wrapper);
+
+    checks = eachSystem (pkgs: {
+      formatting = treefmtEval.${pkgs.system}.config.build.check self;
+    });
   };
 }
diff --git a/rust/treefmt.nix b/rust/treefmt.nix
new file mode 100644
index 0000000..0fd0611
--- /dev/null
+++ b/rust/treefmt.nix
@@ -0,0 +1,6 @@
+{
+  projectRootFile = "treefmt.nix";
+
+  programs.alejandra.enable = true;
+  programs.rustfmt.enable = true;
+}