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tagless-final-parsing/parser-initial/app/Main.hs

53 lines
1.4 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
module Main where
import qualified Parser as P
import qualified Text.Megaparsec as M
import Data.Text (Text)
import Data.Text.IO (hGetContents)
import Options.Applicative
import System.Environment (getArgs)
import System.IO (IOMode(ReadMode), openFile)
data Args = Args
{ argsFileName :: !FilePath
, argsMethod :: !Text
}
args :: Parser Args
args = Args
<$> strArgument (metavar "FILENAME" <> help "The file we want to parse.")
<*> strOption
( short 'm'
<> long "method"
<> metavar "METHOD"
<> showDefault
<> value "naive"
<> help "The parse strategy we want to try. Should be one of \
\\"naive\", \"mul_pass\", or \"mem_cons\"."
)
run :: Args -> IO ()
run args = do
let method = case argsMethod args of
"naive" -> P.naiveExpr
"mul_pass" -> P.mulPassExpr
"mem_cons" -> P.memConsExpr
_ -> error "Encountered an invalid parsing strategy."
handle <- openFile (argsFileName args) ReadMode
contents <- hGetContents handle
case M.parse (method <* M.eof) (argsFileName args) contents of
Left e -> print $ M.errorBundlePretty e
Right a -> print $ P.eval a
main :: IO ()
main = run =<< execParser opts
where
opts = info (args <**> helper)
( fullDesc
<> progDesc "Different parsing strategies using initial encoding"
<> header "Initial encoding parsing"
)