Add nixfmt tool

.github/workflows/ci.yaml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+      - nixfmt
 
   pull_request:
     branches:
@@ -26,6 +27,8 @@ jobs:
             cmd: "nix run .#fourmolu -- --help"
           - name: "hlint"
             cmd: "nix run .#hlint -- --help"
+          - name: "nixfmt"
+            cmd: "nix run .#nixfmt"
           - name: "nixpkgs-fmt"
             cmd: "nix run .#nixpkgs-fmt"
           - name: "ormolu"

README.md

@@ -28,6 +28,7 @@
 [![Static Badge](https://img.shields.io/badge/hie-0.1.4.0-orange)](#hie)
 
 ###### Nix Formatters
+[![Static Badge](https://img.shields.io/badge/nixfmt-?.?.?-orange)](#nixfmt)
 [![Static Badge](https://img.shields.io/badge/nixpkgs--fmt-1.3.0-orange)](#nixpkgs-fmt)
 
 </div>
@@ -216,6 +217,20 @@ nix run github:tbidne/nix-hs-tools#hie
 
 ## Nix Formatters
 
+### Nixfmt
+
+**Source:** https://github.com/serokell/nixfmt
+
+**Description:** The `nixfmt` formatter. Recursively formats all `*.nix` files in the current directory or `--dir`.
+
+**Usage:** `nixfmt [--dir PATH] <args>`.
+
+**Examples:**
+
+```
+nix run github:tbidne/nix-hs-tools#nixpkgs-fmt
+```
+
 ### Nixpkgs-Fmt
 
 **Source:** https://github.com/nix-community/nixpkgs-fmt

flake.nix

@@ -52,6 +52,7 @@
             \tHaskell Miscellaneous:
             \t  - hie:         ${compiler.implicit-hie.version}
             \tNix Formatters:
+            \t  - nixfmt:      ${pkgs.nixfmt.version}
             \t  - nixpkgs-fmt: ${pkgs.nixpkgs-fmt.version}
             \tInformation:
             \t  - help
@@ -79,6 +80,7 @@
 
             hie = import ./tools/hie.nix compilerPkgs;
             hlint = import ./tools/hlint.nix compilerPkgs;
+            nixfmt = import ./tools/nixfmt.nix { inherit nix-hs-utils pkgs; };
             nixpkgs-fmt = import ./tools/nixpkgs-fmt.nix { inherit nix-hs-utils pkgs; };
             ormolu = import ./tools/ormolu.nix compilerPkgs;
             stylish = import ./tools/stylish.nix compilerPkgs;

tools/nixfmt.nix

@@ -0,0 +1,29 @@
+{ nix-hs-utils
+, pkgs
+}:
+
+nix-hs-utils.mkShellApp {
+  inherit pkgs;
+  name = "nixfmt";
+  text = ''
+    set -e
+    args=()
+    dir=.
+    while [ $# -gt 0 ]; do
+      if [[ $1 == "--nh-help" ]]; then
+        echo "usage: nixfmt [--dir PATH] <args>"
+        exit 0
+      elif [[ $1 == "--dir" ]]; then
+        dir=$2
+        shift 1
+      else
+        args+=("$1")
+      fi
+      shift
+    done
+
+    # shellcheck disable=SC2086
+    ${pkgs.nixfmt}/bin/nixfmt $dir "''${args[@]}"
+  '';
+  runtimeInputs = [ pkgs.nixfmt ];
+}