gulcii-0.3: src/Command.hs

{-
    gulcii -- graphical untyped lambda calculus interpreter
    Copyright (C) 2011, 2013, 2017  Claude Heiland-Allen

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-}

module Command (Command(..), parse) where

import Control.Applicative ((<$>), (<*>), (<$), (<*), (<|>))

import qualified Sugar as S
import qualified Meta as M
import Parse

data Command = Define String S.Term | Evaluate S.Term | Meta M.Meta
  deriving (Read, Show, Eq, Ord)

parse :: Parser String Command
parse =  (Define   <$> name <* sym "=" <*> S.parse)
     <|> (Evaluate <$> S.parse)
     <|> (Meta     <$  sym ":" <*> M.parse)