Split the command line parsing into a separate module

digital-asset · neil-da · Jun 26, 2019 · Jun 26, 2019 · Jun 26, 2019 · Jun 26, 2019
commit d3a464f0f5875729f4e685e1761a05cb09341e38
diff --git a/compiler/hie-core/exe/Arguments.hs b/compiler/hie-core/exe/Arguments.hs
@@ -0,0 +1,25 @@
+-- Copyright (c) 2019 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
+-- SPDX-License-Identifier: Apache-2.0
+
+module Arguments(Arguments(..), getArguments) where
+
+import Options.Applicative
+
+
+data Arguments = Arguments
+    {argLSP :: Bool
+    ,argFiles :: [FilePath]
+    }
+
+getArguments :: IO Arguments
+getArguments = execParser opts
+  where
+    opts = info (arguments <**> helper)
+      ( fullDesc
+     <> progDesc "Used as a test bed to check your IDE will work"
+     <> header "hie-core - the core of a Haskell IDE")
+
+arguments :: Parser Arguments
+arguments = Arguments
+      <$> switch (long "lsp" <> help "Start talking to an LSP server")
+      <*> many (argument str (metavar "FILES..."))
diff --git a/compiler/hie-core/exe/Main.hs b/compiler/hie-core/exe/Main.hs
@@ -3,6 +3,7 @@
 
 module Main(main) where
 
+import Arguments
 import Data.Maybe
 import Control.Concurrent.Extra
 import Control.Monad
@@ -45,7 +46,7 @@ main = do
     -- WARNING: If you write to stdout before runLanguageServer
     --          then the language server will not work
     hPutStrLn stderr "Starting hie-core Demo"
-    args <- getArgs
+    Arguments{..} <- getArguments
     -- lock to avoid overlapping output on stdout
     lock <- newLock
     let logger = makeOneLogger $ withLock lock . T.putStrLn
@@ -57,13 +58,13 @@ main = do
 
     let options = defaultIdeOptions $ liftIO $ newSession' cradle
 
-    if "--lsp" `elem` args then do
+    if argLSP then do
         hPutStrLn stderr "Starting IDE server"
         runLanguageServer def def $ \event vfs -> do
             hPutStrLn stderr "Server started"
             initialise (mainRule >> action kick) event logger options vfs
     else do
-        let files = map toNormalizedFilePath $ filter (/= "--lsp") args
+        let files = map toNormalizedFilePath argFiles
         vfs <- makeVFSHandle
         ide <- initialise mainRule (showEvent lock) logger options vfs
         setFilesOfInterest ide $ Set.fromList files

diff --git a/compiler/hie-core/hie-core.cabal b/compiler/hie-core/hie-core.cabal
@@ -109,6 +109,7 @@ executable hie-core
         base == 4.*,
         containers,
         directory,
+        optparse-applicative,
         hie-bios,
         shake,
         data-default,
@@ -118,6 +119,8 @@ executable hie-core
         haskell-lsp,
         text,
         hie-core
+    other-modules:
+        Arguments
 
     default-extensions:
         TupleSections