On Thu, Jan 20, 2011 at 4:19 AM, Magicloud Magiclouds
Hi, Originally, my idea for networking programming is like: read some bytes, judge if this is enough for a packet (defined in certain protocol), if not, read more until the packet is complete, then parse it into a message.
I'd say this is the easiest way to get started with network programming in Haskell as well. For many applications there's a better alternative, based on a concept called iteratees. It takes a bit longer to grasp but deals with a number of problems you often have to deal with in network programming (e.g. chunk boundaries). Check out the enumerator package: http://hackage.haskell.org/package/enumerator
Now we have lazy in Haskell. Can I do it as: buffer <- hGetContents handle (message1, leftData1) <- parse1 buffer
You can. There are a few pitfalls however: * If you close the handler before consuming 'buffer' all the data in the Handle will not have been read into 'buffer'. * You must make sure you consume all of 'buffer' to make sure that the Handle gets closed. * You must under no circumstances read only parts of 'buffer' and hold on to the result for an extended point of time as this will cause the underlying OS resources to be held up longer than desired (i.e. a space leak). Johan