diff --git a/src/Data/Language/Ruby.hs b/src/Data/Language/Ruby.hs
index 4bee141..ffec1bd 100644
--- a/src/Data/Language/Ruby.hs
+++ b/src/Data/Language/Ruby.hs
@@ -2,6 +2,38 @@
 {-# OPTIONS_GHC -Wall #-}
 module Data.Language.Ruby
   ( module Data.Language.Ruby.AST
+  , parse
+  , parseFile
   ) where
 
+import Data.Aeson (eitherDecode)
+import Data.ByteString.Lazy (ByteString)
 import Data.Language.Ruby.AST
+import Frelude
+import System.IO (hFlush)
+import System.IO.Temp (withSystemTempFile)
+import System.Process (readProcess)
+import qualified Data.ByteString.Lazy.Char8 as ByteString
+
+decodeFail :: MonadFail m => FromJSON a => ByteString -> m a
+decodeFail s = case eitherDecode s of
+  Left err -> Frelude.fail err
+  Right a -> pure a
+
+runRubyParseFile :: FilePath -> IO String
+runRubyParseFile p = sh "ruby-parse" ["--emit-json", "--25", p]
+
+runRubyParse :: ByteString -> IO String
+runRubyParse s = withSystemTempFile "rubyhs" $ \p h -> do
+  ByteString.hPut h s
+  hFlush h
+  runRubyParseFile p
+
+sh :: String -> [String] -> IO String
+sh cmd a = readProcess cmd a mempty
+
+parseFile :: FromJSON a => FilePath -> IO a
+parseFile = runRubyParseFile >=> decodeFail . ByteString.pack
+
+parse :: FromJSON a => ByteString -> IO a
+parse = runRubyParse >=> decodeFail . ByteString.pack
diff --git a/src/Rubyhs.hs b/src/Rubyhs.hs
index 99877af..fbeb7cc 100644
--- a/src/Rubyhs.hs
+++ b/src/Rubyhs.hs
@@ -2,51 +2,42 @@
 {-# OPTIONS_GHC -Wall #-}
 module Rubyhs (main) where
 
-import Control.Monad.Fail (MonadFail)
-import Data.Aeson (eitherDecode, encode)
-import Data.ByteString.Lazy (ByteString)
 import Data.Foldable (traverse_)
 import Data.Language.Ruby (Block)
-import Frelude
-import System.Process (readProcess)
-import qualified Data.ByteString.Lazy.Char8 as ByteString
-import qualified Rubyhs.References
-import Options.Applicative (Parser)
-import qualified Options.Applicative as Options
-import System.IO.Temp (withSystemTempFile)
-import System.IO (hFlush)
+import qualified Data.Language.Ruby as Ruby
 import Data.Tree (Tree(Node), Forest)
+import Frelude
+import Options.Applicative (Parser)
 import qualified Data.Aeson as Aeson
+import qualified Data.ByteString.Lazy.Char8 as ByteString
+import qualified Options.Applicative as Options
+import qualified Rubyhs.References
 
 main :: IO ()
 main = do
   Command{targets, printAST} <- getCommand
-  blocks <- decodeInput @Block targets
+  blocks <- parseInput @Block targets
   if printAST
   then traverse_ @[] putEncoded blocks
   else do
     traverse_ (putEncoded . Rubyhs.References.references) blocks
-    traverse_ (ByteString.putStrLn . encode . toJSONForest . Rubyhs.References.graph) blocks
+    traverse_ (ByteString.putStrLn . Aeson.encode . toJSONForest . Rubyhs.References.graph) blocks
 
 toJSONForest :: Forest Rubyhs.References.Node -> Aeson.Value
 toJSONForest = Aeson.Object . fromList . fmap go
   where
   go (Node x xs) = (Rubyhs.References.prettyContext x, toJSONForest xs)
 
--- | Decode from files and mappends the stuff from stdin.
-decodeInput :: FromJSON a => [FilePath] -> IO [a]
-decodeInput = \case
-  [] -> ByteString.getContents >>= fmap pure . decode
-  ps -> traverse decodeFile ps
+-- | If arguments is non-empty treat all arguments as filepaths and
+-- parse the modules at those locations.  If there are no arguments,
+-- parse from stdin.
+parseInput :: FromJSON a => [FilePath] -> IO [a]
+parseInput = \case
+  [] -> ByteString.getContents >>= fmap pure . Ruby.parse
+  ps -> traverse Ruby.parseFile ps
 
 putEncoded :: ToJSON a => a -> IO ()
-putEncoded = ByteString.putStrLn . encode
-
-decodeFile :: FromJSON a => FilePath -> IO a
-decodeFile = runRubyParseFile >=> decodeFail . ByteString.pack
-
-decode :: FromJSON a => ByteString -> IO a
-decode = runRubyParse >=> decodeFail . ByteString.pack
+putEncoded = ByteString.putStrLn . Aeson.encode
 
 data Command = Command
   { targets  :: [FilePath]
@@ -68,20 +59,3 @@ getCommand = Options.execParser opts
       ( Options.fullDesc
      <> Options.progDesc "Static analysis of Ruby"
      <> Options.header "rubyhs - Static analysis of Ruby" )
-
-decodeFail :: MonadFail m => FromJSON a => ByteString -> m a
-decodeFail s = case eitherDecode s of
-  Left err -> Frelude.fail err
-  Right a -> pure a
-
-runRubyParseFile :: FilePath -> IO String
-runRubyParseFile p = sh "ruby-parse" ["--emit-json", "--25", p]
-
-runRubyParse :: ByteString -> IO String
-runRubyParse s = withSystemTempFile "rubyhs" $ \p h -> do
-  ByteString.hPut h s
-  hFlush h
-  runRubyParseFile p
-
-sh :: String -> [String] -> IO String
-sh cmd args = readProcess cmd args mempty