Safe Haskell	None
Language	Haskell2010

HaskellWorks.Data.Conduit.Merge

Synopsis

data JoinResult a v b
- = LeftoverL a
- | JoinValue v
- | LeftoverR b
joinSources :: Monad m => (a -> b -> ([a], [v], [b])) -> ConduitT () a m () -> ConduitT () b m () -> ConduitT () (JoinResult a v b) m ()
joinResumableSources :: Monad m => (a -> b -> ([a], [v], [b])) -> SealedConduitT () a m () -> SealedConduitT () b m () -> ConduitT () (JoinResult a v b) m ()

Documentation

data JoinResult a v b Source #

A result value of joining two sources.

When sources are joined, the result value can be a value or it be a leftover on either left or right side in case if one of the streams is ehausted before another.

Constructors

LeftoverL a	Leftover on the left side, the right side is exhausted
JoinValue v	Result value
LeftoverR b	Leftover on the right side, the left side is exhausted

Instances

(Eq a, Eq v, Eq b) => Eq (JoinResult a v b) Source #
Instance details Defined in HaskellWorks.Data.Conduit.Merge Methods (==) :: JoinResult a v b -> JoinResult a v b -> Bool # (/=) :: JoinResult a v b -> JoinResult a v b -> Bool #
(Show a, Show v, Show b) => Show (JoinResult a v b) Source #
Instance details Defined in HaskellWorks.Data.Conduit.Merge Methods showsPrec :: Int -> JoinResult a v b -> ShowS # show :: JoinResult a v b -> String # showList :: [JoinResult a v b] -> ShowS #

joinSources Source #

Arguments

:: Monad m
=> (a -> b -> ([a], [v], [b]))	Function to merge values. The result contains values `v` and possible leftovers `a` and `b` for left and right streams.
-> ConduitT () a m ()	Left side source
-> ConduitT () b m ()	Right side source
-> ConduitT () (JoinResult a v b) m ()	Result source that can contain a value or leftovers on each side

Joins sources with the provided merging function. Leftovers are considered valid values and are retuned as a part of a result stream.

  import Data.Conduit
  import Data.Conduit.List as CL

  -- combining function just sums both values
  comb :: (Ord a, Num a) => a -> a -> ([a], [a], [a])
  comb a b
    | a > b     = ([a - b], [b], [])
    | b > a     = ([], [a], [b - a])
    | otherwise = ([], [a], [])

  let lst1 = CL.sourceList [1,2,3]
  let lst2 = CL.sourceList [1,2,3,4,5]
  runConduit $ joinSources comb lst1 lst2 $$ CL.take 1000

  [JoinValue 2,JoinValue 4,JoinValue 6,LeftoverR 4,LeftoverR 5]

joinResumableSources Source #

Arguments

:: Monad m
=> (a -> b -> ([a], [v], [b]))	Function to merge values. The result contains values `v` and possible leftovers `a` and `b` for left and right streams.
-> SealedConduitT () a m ()	Left side source
-> SealedConduitT () b m ()	Right side source
-> ConduitT () (JoinResult a v b) m ()	Result source that can contain a value or leftovers on each side