Determine Hamlet, Cassius and Julius templates used by a Yesod application

find-templates.hs

{-# LANGUAGE OverloadedStrings #-}
import Language.Haskell.Parser
import Language.Haskell.Syntax
import System.Environment
import qualified Data.Text.Lazy as T
import qualified Data.Text.Lazy.IO as T
import Data.Attoparsec.Text.Lazy
import Control.Applicative ((<|>))
import Data.Maybe (catMaybes)
import Data.Char (isSpace)

main = do
    [x] <- getArgs
    y <- T.readFile x
    let z = parse (many $ (parser <|> (anyChar >> return Nothing))) y
    case z of
        Fail{} -> return ()
        Done _ r -> print $ catMaybes r

data TempType = Hamlet | Cassius | Julius | Widget
    deriving Show

parser = do
    typ <- (string "$(hamletFile " >> return Hamlet)
       <|> (string "$(cassiusFile " >> return Cassius)
       <|> (string "$(juliusFile " >> return Julius)
       <|> (string "$(widgetFile " >> return Widget)
    skipWhile isSpace
    _ <- char '"'
    x <- many1 $ satisfy (/= '"')
    _ <- char '"'
    skipWhile isSpace
    _ <- char ')'
    return $ Just (typ, x)

gistfile2.txt