ci: add code format check

.envrc

@@ -0,0 +1 @@
+use nix

.github/workflows/test.yml

@@ -8,3 +8,10 @@ jobs:
       - uses: nixbuild/nix-quick-install-action@v28
       - name: Structural Integirty Test
         run: cd test && ./bld.sh
+  format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: nixbuild/nix-quick-install-action@v28
+      - name: Code Format Check
+        run: eval "$(nix print-dev-env -f shell.nix)" && treefmt --fail-on-change

.gitignore

@@ -0,0 +1 @@
+.direnv

dev/mod.nix

@@ -0,0 +1 @@
+{ }

dev/shell.nix

@@ -0,0 +1,11 @@
+{
+  pkgs ? import <nixpkgs> { },
+}:
+pkgs.mkShell {
+  packages = with pkgs; [
+    treefmt
+    npins
+    nixfmt-rfc-style
+    shfmt
+  ];
+}

shell.nix

@@ -0,0 +1,4 @@
+let
+  dev = import ./. ./dev;
+in
+dev.shell

test/bld.res.nix

@@ -42,6 +42,6 @@
     g = 5;
     h = 8;
   };
-  test = scopedImport {std = builtins;} "${../std/set/filterMap.nix}";
+  test = scopedImport { std = builtins; } "${../std/set/filterMap.nix}";
   x = builtins.readFile ./bld/bum;
 }

treefmt.toml

@@ -0,0 +1,11 @@
+[formatter.nix]
+command = "nixfmt"
+options = []
+includes = [ "*.nix" ]
+excludes = []
+
+[formatter.sh]
+command = "shfmt"
+options = []
+includes = [ "*.sh" ]
+excludes = []