Enumerators/Iteratees as an abstraction were invented by Oleg Kiselyov. They provide a clean way of doing IO with predictable (low) resource requirements. The current Enumerators package is pretty close to Oleg’s original work. Conduits were created for the Yesod web framework. My understanding is that they were designed to be blazingly fast. Early versions of … Read more
Lazy IO Lazy IO works like this readFile :: FilePath -> IO ByteString where ByteString is guaranteed to only be read chunk-by-chunk. To do so we could (almost) write — given `readChunk` which reads a chunk beginning at n readChunk :: FilePath -> Int -> IO (Int, ByteString) readFile fp = readChunks 0 where readChunks … Read more
I don’t know if it’s any help, but I tried to implement Iain’s suggestion and made a variant of mergeSources’ that stops as soon as any of the channels does: mergeSources’ :: (MonadIO m, MonadBaseControl IO m) => [Source (ResourceT m) a] — ^ The sources to merge. -> Int — ^ The bound of … Read more