Add format CLI subcommand

builder/src/AbsoluteSrcDir.hs

@@ -0,0 +1,25 @@
+module AbsoluteSrcDir
+  ( AbsoluteSrcDir (..),
+    fromFilePath,
+    addRelative,
+    toFilePath,
+  )
+where
+
+import qualified System.Directory as Dir
+import System.FilePath ((</>))
+
+newtype AbsoluteSrcDir
+  = AbsoluteSrcDir FilePath
+
+toFilePath :: AbsoluteSrcDir -> FilePath
+toFilePath (AbsoluteSrcDir path) = path
+
+fromFilePath :: FilePath -> IO AbsoluteSrcDir
+fromFilePath srcDir =
+  AbsoluteSrcDir
+    <$> Dir.canonicalizePath srcDir
+
+addRelative :: AbsoluteSrcDir -> FilePath -> FilePath
+addRelative (AbsoluteSrcDir srcDir) path =
+  srcDir </> path

builder/src/Build.hs

@@ -20,6 +20,8 @@ where
 import qualified AST.Canonical as Can
 import qualified AST.Optimized as Opt
 import qualified AST.Source as Src
+import AbsoluteSrcDir (AbsoluteSrcDir (..))
+import qualified AbsoluteSrcDir
 import qualified Compile
 import Control.Concurrent (forkIO)
 import Control.Concurrent.MVar
@@ -75,31 +77,13 @@ makeEnv key root (Details.Details _ validOutline buildID locals foreigns _) =
   case validOutline of
     Details.ValidApp givenSrcDirs ->
       do
-        srcDirs <- traverse (toAbsoluteSrcDir root) (NE.toList givenSrcDirs)
+        srcDirs <- traverse (Outline.toAbsoluteSrcDir root) (NE.toList givenSrcDirs)
         return $ Env key root Parse.Application srcDirs buildID locals foreigns
     Details.ValidPkg pkg _ _ ->
       do
-        srcDir <- toAbsoluteSrcDir root (Outline.RelativeSrcDir "src")
+        srcDir <- Outline.toAbsoluteSrcDir root (Outline.RelativeSrcDir "src")
         return $ Env key root (Parse.Package pkg) [srcDir] buildID locals foreigns
 
--- SOURCE DIRECTORY
-
-newtype AbsoluteSrcDir
-  = AbsoluteSrcDir FilePath
-
-toAbsoluteSrcDir :: FilePath -> Outline.SrcDir -> IO AbsoluteSrcDir
-toAbsoluteSrcDir root srcDir =
-  AbsoluteSrcDir
-    <$> Dir.canonicalizePath
-      ( case srcDir of
-          Outline.AbsoluteSrcDir dir -> dir
-          Outline.RelativeSrcDir dir -> root </> dir
-      )
-
-addRelative :: AbsoluteSrcDir -> FilePath -> FilePath
-addRelative (AbsoluteSrcDir srcDir) path =
-  srcDir </> path
-
 -- FORK
 
 -- PERF try using IORef semephore on file crawl phase?
@@ -242,7 +226,7 @@ crawlModule env@(Env _ root projectType srcDirs buildID locals foreigns) mvar do
   do
     let fileName = ModuleName.toFilePath name <.> "gren"
 
-    paths <- filterM File.exists (map (`addRelative` fileName) srcDirs)
+    paths <- filterM File.exists (map (`AbsoluteSrcDir.addRelative` fileName) srcDirs)
 
     case paths of
       [path] ->
@@ -899,8 +883,8 @@ getRootInfoHelp (Env _ _ _ srcDirs _ _ _) path absolutePath =
                     case matchingDirs of
                       d1 : d2 : _ ->
                         do
-                          let p1 = addRelative d1 (FP.joinPath names <.> "gren")
-                          let p2 = addRelative d2 (FP.joinPath names <.> "gren")
+                          let p1 = AbsoluteSrcDir.addRelative d1 (FP.joinPath names <.> "gren")
+                          let p2 = AbsoluteSrcDir.addRelative d2 (FP.joinPath names <.> "gren")
                           return $ Left $ Exit.BP_RootNameDuplicate name p1 p2
                       _ ->
                         return $ Right $ RootInfo absolutePath path (LInside name)
@@ -911,7 +895,7 @@ getRootInfoHelp (Env _ _ _ srcDirs _ _ _) path absolutePath =
 
 isInsideSrcDirByName :: [String] -> AbsoluteSrcDir -> IO Bool
 isInsideSrcDirByName names srcDir =
-  File.exists (addRelative srcDir (FP.joinPath names <.> "gren"))
+  File.exists (AbsoluteSrcDir.addRelative srcDir (FP.joinPath names <.> "gren"))
 
 isInsideSrcDirByPath :: [String] -> AbsoluteSrcDir -> Maybe (FilePath, Either [String] [String])
 isInsideSrcDirByPath segments (AbsoluteSrcDir srcDir) =

builder/src/Gren/Outline.hs

@@ -14,9 +14,14 @@ module Gren.Outline
     decoder,
     defaultSummary,
     flattenExposed,
+    toAbsoluteSrcDir,
+    sourceDirs,
+    testDirs,
   )
 where
 
+import AbsoluteSrcDir (AbsoluteSrcDir)
+import qualified AbsoluteSrcDir
 import Control.Monad (filterM, liftM)
 import Data.Binary (Binary, get, getWord8, put, putWord8)
 import qualified Data.Map as Map
@@ -204,6 +209,10 @@ toAbsolute root srcDir =
     AbsoluteSrcDir dir -> dir
     RelativeSrcDir dir -> root </> dir
 
+toAbsoluteSrcDir :: FilePath -> SrcDir -> IO AbsoluteSrcDir
+toAbsoluteSrcDir root srcDir =
+  AbsoluteSrcDir.fromFilePath (toAbsolute root srcDir)
+
 detectDuplicates :: FilePath -> [SrcDir] -> IO (Maybe (FilePath, (FilePath, FilePath)))
 detectDuplicates root srcDirs =
   do
@@ -225,6 +234,18 @@ isDup paths =
     OneOrMore.One _ -> Nothing
     OneOrMore.More a b -> Just (OneOrMore.getFirstTwo a b)
 
+sourceDirs :: Outline -> NE.List SrcDir
+sourceDirs outline =
+  case outline of
+    App (AppOutline _ srcDirs _ _ _ _) ->
+      srcDirs
+    Pkg _ ->
+      NE.singleton (RelativeSrcDir "src")
+
+testDirs :: Outline -> NE.List SrcDir
+testDirs _ =
+  NE.singleton (RelativeSrcDir "tests")
+
 -- JSON DECODE
 
 type Decoder a =

builder/src/Reporting/Exit.hs

@@ -17,6 +17,8 @@ module Reporting.Exit
     installToReport,
     Reactor (..),
     reactorToReport,
+    Format (..),
+    formatToReport,
     newPackageOverview,
     --
     Solver (..),
@@ -2448,3 +2450,45 @@ replToReport problem =
       corruptCacheReport
     ReplBlocked ->
       corruptCacheReport
+
+-- FORMAT
+
+data Format
+  = FormatPathUnknown FilePath
+  | FormatStdinWithFiles
+  | FormatNoOutline
+  | FormatBadOutline Outline
+
+formatToReport :: Format -> Help.Report
+formatToReport problem =
+  case problem of
+    FormatPathUnknown path ->
+      Help.report
+        "FILE NOT FOUND"
+        Nothing
+        "I cannot find this file:"
+        [ D.indent 4 $ D.red $ D.fromChars path,
+          D.reflow $ "Is there a typo?",
+          D.toSimpleNote $
+            "If you are just getting started, try working through the examples in the\
+            \ official guide https://guide.gren-lang.org to get an idea of the kinds of things\
+            \ that typically go in a src/Main.gren file."
+        ]
+    FormatStdinWithFiles ->
+      Help.report
+        "INCOMPATIBLE FLAGS"
+        Nothing
+        "Files and stdin cannot be formatted at the same time."
+        [ D.reflow "You'll need to run `gren format` two separate times if you want to do both."
+        ]
+    FormatNoOutline ->
+      Help.report
+        "FORMAT WHAT?"
+        Nothing
+        "I cannot find a gren.json so I am not sure what you want me to format.\
+        \ Normally you run `gren format` from within a project!"
+        [ D.reflow $ "If you need to format gren files outside of a project, tell me which files or directories to format:",
+          D.indent 4 $ D.green $ "gren format Example.gren"
+        ]
+    FormatBadOutline outline ->
+      toOutlineReport outline

compiler/src/Reporting/Doc.hs

@@ -26,6 +26,7 @@ module Reporting.Doc
     P.dullred,
     P.dullcyan,
     P.dullyellow,
+    P.dullwhite,
     --
     fromChars,
     fromName,

gren.cabal

@@ -54,6 +54,7 @@ Executable gren
     other-modules:
         Bump
         Diff
+        Format
         Init
         Install
         Make
@@ -68,6 +69,7 @@ Executable gren
         Terminal.Internal
 
         -- from builder/
+        AbsoluteSrcDir
         Build
         BackgroundWriter
         Deps.Diff

terminal/impl/Terminal/Helpers.hs

@@ -3,6 +3,7 @@
 module Terminal.Helpers
   ( version,
     grenFile,
+    grenFileOrDirectory,
     package,
   )
 where
@@ -72,6 +73,18 @@ exampleGrenFiles :: String -> IO [String]
 exampleGrenFiles _ =
   return ["Main.gren", "src/Main.gren"]
 
+-- GREN FILE OR DIRECTORY
+
+grenFileOrDirectory :: Parser FilePath
+grenFileOrDirectory =
+  Parser
+    { _singular = "gren file or directory",
+      _plural = "gren files and/or directories",
+      _parser = Just,
+      _suggest = \_ -> return [],
+      _examples = \_ -> return ["Main.gren", "src/Examples/"]
+    }
+
 -- PACKAGE
 
 package :: Parser Pkg.Name