BF.hs

-- Copyright (c) 2006 Jason Dagit - http://www.codersbase.com/
-- GPL version 2 or later (see http://www.gnu.org/copyleft/gpl.html)

-- | A plugin for the Haskell interpreter for the brainf*ck language
-- http://www.muppetlabs.com/~breadbox/bf/
module Lambdabot.Plugin.BF (theModule) where

import Lambdabot.Plugin
import Lambdabot.Util.Process

import Data.Char
import Text.Regex.TDFA

theModule :: Module ()
theModule = newModule
    { moduleCmds = return
        [ (command "bf")
            { help = say "bf <expr>. Evaluate a brainf*ck expression"
            , process = \msg -> do
                bf <- getConfig bfBinary
                ios80 (run bf msg scrub)
            }
        ]
    }

-- Clean up output
scrub :: String -> String
scrub = unlines . take 6 . map (' ':) . filter (not.null) . map cleanit . lines

cleanit :: String -> String
cleanit s | s =~ terminated   = "Terminated\n"
          | otherwise         = filter printable s
    where terminated = "waitForProc"
          -- the printable ascii chars are in the range [32 .. 126]
          -- according to wikipedia:
          -- http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters
          printable x = 31 < ord x && ord x < 127