separate_patch.hs

module Main where

import System
import Data.List
import Control.Monad

separateDiffPatch :: String -> [String]
separateDiffPatch str = map unlines . map (head . filter patchEnd . inits) . (filter patchStart . tails) . lines $ str
	where
		patchStart (l0 : l1 : l2 : ls) = and [isPrefixOf "From " l0, isPrefixOf "From: " l1, isPrefixOf "Date: " l2]
		patchStart _ = False
		--
		patchEnd ss = isSuffixOf ["1.7.5.1", ""] ss

main = do
	args <- getArgs
	let fn = args !! 0
	contents <- readFile fn
	let eachFNs = map (\n -> fn ++ "." ++ show n) [1..]
	let eachPatches = separateDiffPatch contents
	zipWithM (writeFile) eachFNs eachPatches
	return ()