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
-  if printAST
-  then traverse_ @[] putEncoded blocks
-  else traverse_ act blocks
-  where
+  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
-    drawDot x
+      case maybeDotPath of
+        Nothing -> pure ()
+        Just dotPath -> drawDot dotPath x
+  if printAST
+  then traverse_ @[] putEncoded blocks
+  else traverse_ act blocks
 
-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
@@ -63,15 +62,22 @@ putEncoded = ByteString.putStrLn . Aeson.encode
 data Command = Command
   { 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