fix(windows): Find purs.exe on Windows, if available

app/Main.hs

@@ -199,16 +199,33 @@ updateImpl config@PackageConfig{ depends } = do
   echoT ("Updating " <> pack (show (length trans)) <> " packages...")
   forConcurrently_ trans . uncurry $ installOrUpdate (set config)
 
+pursCmd :: IO Text
+pursCmd = do
+  purs <- which "purs"
+  cmd <- which "purs.cmd"
+  exe <- which "purs.exe"
+  let mpurs = msum [ "purs" <$ purs
+                   , "purs" <$ exe
+                   , "purs.cmd" <$ cmd
+                   ]
+  case mpurs of
+    Nothing -> exitWithErr "The \"purs\" executable could not be found. Please make sure your PATH variable is set correctly"
+    Just c -> return c
+
 getPureScriptVersion :: IO Version
 getPureScriptVersion = do
-  let pursProc = inproc "purs" [ "--version" ] empty
+  purs <- pursCmd
+  let pursProc = cmdProc purs
   outputLines <- Turtle.fold (fmap lineToText pursProc) Foldl.list
   case outputLines of
     [onlyLine]
       | results@(_ : _) <- Read.readP_to_S parseVersion (T.unpack onlyLine) ->
            pure (fst (maximumBy (comparing (length . versionBranch . fst)) results))
       | otherwise -> exitWithErr "Unable to parse output of purs --version"
     _ -> exitWithErr "Unexpected output from purs --version"
+    where
+      cmdProc "purs.cmd" = inshell "purs.cmd --version" empty
+      cmdProc purs = inproc purs [ "--version" ] empty
 
 initialize :: Maybe (Text, Maybe Text) -> IO ()
 initialize setAndSource = do
@@ -327,24 +344,30 @@ listSourcePaths = do
 --
 -- Extra args will be appended to the options
 exec :: [String] -> Bool -> [String] -> IO ()
-exec execNames onlyDeps passthroughOptions = do
+exec cmdParts onlyDeps passthroughOptions = do
   pkg <- readPackageFile
   updateImpl pkg
 
+  purs <- T.unpack <$> pursCmd
   paths <- getPaths
-  let cmdParts = tail execNames
-      srcParts = [ "src" </> "**" </> "*.purs" | not onlyDeps ]
+  let srcParts = [ "src" </> "**" </> "*.purs" | not onlyDeps ]
   exit
     =<< Process.waitForProcess
-    =<< Process.runProcess
-          (head execNames)
-          (cmdParts <> passthroughOptions
-                    <> map Path.encodeString (srcParts <> paths))
-          Nothing -- no special path to the working dir
-          Nothing -- no env vars
-          Nothing -- use existing stdin
-          Nothing -- use existing stdout
-          Nothing -- use existing stderr
+    =<< run purs paths srcParts
+    where
+      run p paths srcParts =
+        let args = (cmdParts <> passthroughOptions) <> map Path.encodeString (srcParts <> paths)
+        in case p of
+          "purs.cmd" -> Process.runCommand $ List.unwords (p : args)
+          _ ->
+            Process.runProcess
+              p
+              args
+              Nothing -- no special path to the working dir
+              Nothing -- no env vars
+              Nothing -- use existing stdin
+              Nothing -- use existing stdout
+              Nothing -- use existing stderr
 
 checkForUpdates :: Bool -> Bool -> IO ()
 checkForUpdates applyMinorUpdates applyMajorUpdates = do
@@ -431,7 +454,7 @@ verify inputName = case mkPackageName (pack inputName) of
     pkg <- readPackageFile
     db <- readPackageSet pkg
     case name `Map.lookup` db of
-      Nothing -> echoT . pack $ "No packages found with the name " <> show (runPackageName $ name)
+      Nothing -> echoT . pack $ "No packages found with the name " <> show (runPackageName name)
       Just _ -> do
         reverseDeps <- map fst <$> getReverseDeps db name
         let packages = pure name <> reverseDeps
@@ -461,7 +484,17 @@ verifyPackage db paths name = do
   echoT ("Verifying package " <> runPackageName name)
   dependencies <- map fst <$> getTransitiveDeps db [name]
   let srcGlobs = map (pathToTextUnsafe . (</> ("src" </> "**" </> "*.purs")) . dirFor) dependencies
-  procs "purs" ("compile" : srcGlobs) empty
+  runPurs srcGlobs
+  where
+    runPurs :: [Text] -> IO ()
+    runPurs globs = do
+      let args = "compile" : globs
+      purs <- pursCmd
+      case purs of
+        "purs.cmd" -> do
+          let s = T.intercalate " " $ purs : args
+          shells s empty
+        _ -> procs purs args empty
 
 main :: IO ()
 main = do
@@ -501,13 +534,13 @@ main = do
             (Opts.info (install <$> pkg Opts.<**> Opts.helper)
             (Opts.progDesc "Install the named package"))
         , Opts.command "build"
-            (Opts.info (exec ["purs", "compile"]
+            (Opts.info (exec ["compile"]
                         <$> onlyDeps "Compile only the package's dependencies"
                         <*> passthroughArgs "purs compile"
                         Opts.<**> Opts.helper)
             (Opts.progDesc "Update dependencies and compile the current package"))
         , Opts.command "repl"
-            (Opts.info (exec ["purs", "repl"]
+            (Opts.info (exec ["repl"]
                         <$> onlyDeps "Load only the package's dependencies"
                         <*> passthroughArgs "purs repl"
                         Opts.<**> Opts.helper)