Add option to exclude globs from given input (purescript#4480)

Author: i-am-the-slime

CHANGELOG.d/feature_exclude_files_from_compile_input.md

@@ -0,0 +1,45 @@
+* Exclude files from compiler input
+
+  The compiler now supports excluding files from the globs given to it as input.
+  This means there's now a new option for `purs compile`, namely
+  `--exclude-files` (or the short version `-x`):
+
+```sh
+> purs compile --help
+Usage: purs compile [FILE] [-x|--exclude-files ARG] [-o|--output ARG] ...
+
+  Compile PureScript source files
+
+Available options:
+  -h,--help                Show this help text
+  FILE                     The input .purs file(s).
+  -x,--exclude-files ARG   Glob of .purs files to exclude from the supplied
+                           files.
+  ...
+```
+
+This allows you to keep related files closer together (that is, [colocate](https://kentcdodds.com/blog/colocation) them).
+
+Consider a setup like the following:
+
+```sh
+src/
+    Main.purs
+    View/
+        LoginPage.purs
+        LoginPageTest.purs
+        LoginPageStories.purs
+```
+
+In order to exclude the files in the example above you can now invoke `purs`
+like this and it will only compile `LoginPage.purs`:
+
+```sh
+purs compile "src/**/*.purs" --exclude-files "src/**/*Stories.purs" -x "src/**/*Test.purs"
+```
+
+With `spago`, the equivalent command is:
+
+```sh
+spago build --purs-args '-x "src/**/*Test.purs" -x "src/**/*Stories.purs"'
+```

app/Command/Compile.hs

@@ -7,7 +7,7 @@ import Control.Monad (when)
 import Data.Aeson qualified as A
 import Data.Bool (bool)
 import Data.ByteString.Lazy.UTF8 qualified as LBU8
-import Data.List (intercalate)
+import Data.List (intercalate, (\\))
 import Data.Map qualified as M
 import Data.Set qualified as S
 import Data.Text qualified as T
@@ -26,6 +26,7 @@ import System.IO.UTF8 (readUTF8FilesT)
 
 data PSCMakeOptions = PSCMakeOptions
   { pscmInput        :: [FilePath]
+  , pscmExclude      :: [FilePath]
   , pscmOutputDir    :: FilePath
   , pscmOpts         :: P.Options
   , pscmUsePrefix    :: Bool
@@ -53,7 +54,9 @@ printWarningsAndErrors verbose True files warnings errors = do
 
 compile :: PSCMakeOptions -> IO ()
 compile PSCMakeOptions{..} = do
-  input <- globWarningOnMisses warnFileTypeNotFound pscmInput
+  included <- globWarningOnMisses warnFileTypeNotFound pscmInput
+  excluded <- globWarningOnMisses warnFileTypeNotFound pscmExclude
+  let input = included \\ excluded
   when (null input) $ do
     hPutStr stderr $ unlines [ "purs compile: No input files."
                              , "Usage: For basic information, try the `--help' option."
@@ -86,6 +89,12 @@ inputFile = Opts.strArgument $
      Opts.metavar "FILE"
   <> Opts.help "The input .purs file(s)."
 
+excludedFiles :: Opts.Parser FilePath
+excludedFiles = Opts.strOption $
+     Opts.short 'x'
+  <> Opts.long "exclude-files"
+  <> Opts.help "Glob of .purs files to exclude from the supplied files."
+
 outputDirectory :: Opts.Parser FilePath
 outputDirectory = Opts.strOption $
      Opts.short 'o'
@@ -153,6 +162,7 @@ options =
 
 pscMakeOptions :: Opts.Parser PSCMakeOptions
 pscMakeOptions = PSCMakeOptions <$> many inputFile
+                                <*> many excludedFiles
                                 <*> outputDirectory
                                 <*> options
                                 <*> (not <$> noPrefix)