Add CLI option for dot path

src/Rubyhs.hs

@@ -19,24 +19,23 @@ import qualified Rubyhs.References
 
 main :: IO ()
 main = do
-  Command{targets, printAST} <- getCommand
+  Command{targets, printAST, maybeDotPath} <- getCommand
   blocks <- parseInput @Block targets
+  let
+    act block = do
+      let res@(Rubyhs.References.Result x) = Rubyhs.References.references $ block
+      putEncoded res
+      ByteString.putStrLn . Aeson.encode . toJSONForest . Rubyhs.References.graph $ block
+      case maybeDotPath of
+        Nothing -> pure ()
+        Just dotPath -> drawDot dotPath x
   if printAST
   then traverse_ @[] putEncoded blocks
   else traverse_ act blocks
-  where
-  act block = do
-    let res@(Rubyhs.References.Result x) = Rubyhs.References.references $ block
-    putEncoded res
-    ByteString.putStrLn . Aeson.encode . toJSONForest . Rubyhs.References.graph $ block
-    drawDot x
 
-graphOut :: FilePath
-graphOut = "out.dot"
-
-drawDot :: Map Rubyhs.References.Node (Set Rubyhs.References.Node)  -> IO ()
-drawDot
-  = Text.writeFile graphOut
+drawDot :: FilePath -> Map Rubyhs.References.Node (Set Rubyhs.References.Node)  -> IO ()
+drawDot p
+  = Text.writeFile p
   . Graphviz.digraph
   . fmap (fmap (qoutes . Rubyhs.References.prettyContext) . \(x, xs) -> x :| toList xs)
   . toList
@@ -61,17 +60,24 @@ putEncoded :: ToJSON a => a -> IO ()
 putEncoded = ByteString.putStrLn . Aeson.encode
 
 data Command = Command
-  { targets  :: [FilePath]
-  , printAST :: Bool
+  { targets       :: [FilePath]
+  , printAST      :: Bool
+  , maybeDotPath  :: Maybe FilePath
   }
 
 command :: Parser Command
-command = Command <$> targets <*> printAST
+command = Command <$> targets <*> printAST <*> dotPath
   where
   targets = many (Options.argument Options.str (Options.metavar "TARGET"))
   printAST = Options.switch
     $  Options.long "print-ast"
     <> Options.help "Print AST and exit"
+  dotPath
+    = Options.optional
+    $ Options.strOption
+    $ Options.long "dot"
+    <> Options.metavar "PATH"
+    <> Options.help "Write dot graph"
 
 getCommand :: IO Command
 getCommand = Options.execParser opts