a3aced6 · distributed-process

33 )

34import Control.Distributed.Process.Internal.StrictList

35 ( StrictList(..)

36+ , append

36 )

37 )

37−import qualified Control.Distributed.Process.Internal.StrictList as S

38import Data.Maybe (fromJust)

39import GHC.MVar (MVar(MVar))

40import GHC.IO (IO(IO))

146 -- of passing around restore and setting up exception handlers is

147 -- high. So just don't use expensive matchIfs!

148 case checkArrived matches old of

149− (old', Just r) -> returnOld old' (Just r)

149+ (old', Just r) -> returnOld old' (Just r)

150− (old', Nothing) -> goCheck rest old'

150+ (old', Nothing) -> goCheck rest old'

151 -- use the result list, which is now left-biased

152

153 --

222

223 -- as a side-effect, this left-biases the list

224 checkArrived :: [m -> Maybe a] -> StrictList m -> (StrictList m, Maybe a)

225− checkArrived matches list = S.foldr f (Nil, Nothing) list

225+ checkArrived matches list = go list Nil

226 where

227− f x (rest,r)

227+ go Nil Nil = (Nil, Nothing)

228+ go Nil r = go r Nil

229+ go (Append xs ys) tl = go xs (append ys tl)

230+ go (Snoc xs x) tl = go xs (Cons x tl)

231+ go (Cons x xs) tl

228− | Just y <- checkMatches matches x = (rest, Just y)

232+ | Just y <- checkMatches matches x = (Append xs tl, Just y)

229 | otherwise = (Cons x rest, r)

233 | otherwise = (Cons x rest, r)

234+ where !(rest,r) = go xs tl

230

235

231 checkMatches :: [m -> Maybe a] -> m -> Maybe a

236 checkMatches :: [m -> Maybe a] -> m -> Maybe a

232 checkMatches [] _ = Nothing

237 checkMatches [] _ = Nothing