Add nixfmt to Lint.hs

nixfmt is the soon-to-be official formatter for Nix code, as per the NixOS
GitHub group. So I figure I should just adopt it without worrying too much about
the specifics of the formatting. I just formatted everything in one go, hence
the huge diff, oh well.

1 files changed, 28 insertions, 8 deletions

diff --git a/Biz/Lint.hs b/Biz/Lint.hs
index 13150cc..d27ca1d 100644
--- a/Biz/Lint.hs
+++ b/Biz/Lint.hs
@@ -15,6 +15,7 @@
 -- : run deadnix
 -- : run shellcheck
 -- : run indent
+-- : run nixfmt
 module Biz.Lint (main) where
 
 import Alpha
@@ -78,8 +79,11 @@ all your lint are belong to us
 
 Usage:
   lint test
-  lint [--fix] [<file>...]
-  lint -h, --help
+  lint [options] [<file>...]
+
+Options:
+  --fix,  -f  Apply fixes automatically
+  --help, -h  Print this info
 |]
 
 exit :: [Result] -> IO ()
@@ -88,7 +92,7 @@ exit results = Exit.exitWith <| (n > 0) ?: (Exit.ExitFailure n, Exit.ExitSuccess
     n = length <| filter bad results
     bad = \case
       (Warn _) -> False
-      Done {status = Bad _} -> True
+      Done _ (Bad _) -> True
       _ -> False
 
 printResult :: Result -> IO Result
@@ -137,8 +141,6 @@ data Linter = Linter
     formatter :: Maybe (String -> String)
   }
 
--- deriving (Show)
-
 ormolu :: Linter
 ormolu =
   Linter
@@ -219,6 +221,15 @@ decodeDeadnixOutput deadnixJson =
         formatDeadnixResult DeadnixResult {..} =
           file <> ":" <> show line <> ":" <> show column <> ": " <> message
 
+nixfmt :: Linter
+nixfmt =
+  Linter
+    { exe = "nixfmt",
+      checkArgs = ["--check"],
+      fixArgs = Nothing,
+      formatter = Nothing
+    }
+
 shellcheck :: Linter
 shellcheck =
   Linter
@@ -241,7 +252,7 @@ data Status = Good | Bad String
   deriving (Show)
 
 data Result
-  = Done {linter :: Linter, status :: Status}
+  = Done Linter Status
   | Warn Text
   | NoOp Namespace.Ext
 
@@ -251,6 +262,7 @@ run mode nsmap = nsmap |> Map.assocs |> traverse (runOne mode) /> concat
 runOne :: Mode -> (Ext, [Namespace]) -> IO [Result]
 runOne mode (ext, ns's) = results +> traverse printResult
   where
+    results :: IO [Result]
     results =
       -- i would run these with mapConcurrently, but the output gets mangled. to
       -- do it right i need a queue for the results. someday.
@@ -264,9 +276,17 @@ runOne mode (ext, ns's) = results +> traverse printResult
             lint mode ruff ns's
           ]
         Namespace.Sh -> [lint mode shellcheck ns's]
-        Namespace.Nix -> [lint mode deadnix ns's]
+        Namespace.Nix -> [lint mode deadnix ns's, lint mode nixfmt ns's]
         Namespace.C -> [lint mode indent ns's]
-        _ -> [pure <. Warn <| "no linter for " <> show ext]
+        _ ->
+          ns's
+            |> map Namespace.toPath
+            |> joinWith ", "
+            |> str
+            |> ("no linter for " <>)
+            |> Warn
+            |> (pure :: Result -> IO Result)
+            |> (pure :: IO Result -> [IO Result])
 
 lint :: Mode -> Linter -> [Namespace] -> IO Result
 lint mode linter@Linter {..} ns's =