conduit-merge (empty) → 0.1.0.0

raw patch · 4 files changed

+84/−0 lines, 4 filesdep +basedep +conduitdep +mtlsetup-changed

Dependencies added: base, conduit, mtl

Files

• LICENSE +30/−0
• Setup.hs +2/−0
• conduit-merge.cabal +29/−0
• src/Data/Conduit/Merge.hs +23/−0

@@ -0,0 +1,30 @@+Copyright Yuriy Syrovetskiy (c) 2016++All rights reserved.++Redistribution and use in source and binary forms, with or without+modification, are permitted provided that the following conditions are met:++    * Redistributions of source code must retain the above copyright+      notice, this list of conditions and the following disclaimer.++    * Redistributions in binary form must reproduce the above+      copyright notice, this list of conditions and the following+      disclaimer in the documentation and/or other materials provided+      with the distribution.++    * Neither the name of Author name here nor the names of other+      contributors may be used to endorse or promote products derived+      from this software without specific prior written permission.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,29 @@+name: conduit-merge+version: 0.1.0.0+cabal-version: >=1.10+build-type: Simple+license: BSD3+license-file: LICENSE+copyright: 2016 Yuriy Syrovetskiy+maintainer: cblp@cblp.su+homepage: https://github.com/cblp/conduit-merge#readme+synopsis: Merge multiple sorted conduits+description:+    See README.md+category: Conduit+author: Yuriy Syrovetskiy++source-repository head+    type: git+    location: https://github.com/cblp/conduit-merge++library+    exposed-modules:+        Data.Conduit.Merge+    build-depends:+        base >=4.7 && <5,+        conduit >=1.2.6.6 && <1.3,+        mtl >=2.2.1 && <2.3+    default-language: Haskell2010+    hs-source-dirs: src+

@@ -0,0 +1,23 @@+{-# LANGUAGE RankNTypes #-}++module Data.Conduit.Merge (mergeSources) where++import Control.Monad.Trans (lift)+import Data.Conduit        (Producer, Source, await, newResumableSource, yield, ($$++))+import Data.List           (sortOn)++mergeSources :: (Ord a, Monad m) => [Source m a] -> Producer m a+mergeSources = mergeResumable . map newResumableSource+  where+    mergeResumable sources = do+        prefetchedSources <- lift $ mapM ($$++ await) sources+        go [(a, s) | (s, Just a) <- prefetchedSources]+    go [] = pure ()+    go sources = do+        let (a, src1) : sources1 = sortOn fst sources+        yield a+        (src2, mb) <- lift $ src1 $$++ await+        let sources2 = case mb of+                Nothing -> sources1+                Just b  -> (b, src2) : sources1+        go sources2