add `format` to shell

1 files changed, 6 insertions, 0 deletions

diff --git a/default.nix b/default.nix
index 43fff14..0bd2ddb 100644
--- a/default.nix
+++ b/default.nix
@@ -32,6 +32,12 @@ rec {
         set -efu
         exec ${haskellPackages.cabal-install}/bin/cabal run acms -- "$@"
       '')
+      (pkgs.writeScriptBin "format" ''
+        set -efu
+        git ls-files | grep .hs$ | while read -r fn; do
+          ${haskellPackages.ormolu}/bin/ormolu -i "$fn" || :
+        done
+      '')
     ];
     withHoogle = true;
     withHaddock = true;