Prelude.hs

{-# LANGUAGE NoMonomorphismRestriction #-}
module My.Prelude where

import System.Posix.Files
import Data.Maybe
import Debug.Trace as Tr
import My.Control.Monad
import qualified Data.ByteString as B
import Data.List
import Data.Char
import Data.Word
import Data.Array

debugMess mess x = Tr.trace (mess++show x) x
debug x = traceShow x x
debugM = liftM debug 
trace = Tr.trace

maybeToEither = maybe (Left undefined) Right
eitherToMaybe = either (const Nothing) Just

ifThenElse b th el = if b then th else el

swap (a,b) = (b,a)
thd (_,_,a) = a

lazyPair ~(a,b) = (a,b)

newerThan f1 f2 = liftM2 (>) (modTime f1) (modTime f2)
  where modTime f = modificationTime $< getFileStatus f

showHex n = reverse $ map (intToDigit . fromIntegral . (`mod`16)) $ take 2 $ iterate (`div`16) (n :: Word8)
showCode code = intercalate " " $ map showHex $ B.unpack $ code

a !# i | bounds a`inRange`i = a!i
       | otherwise = error $ "undefined index "++show i++" in array "