Marco Righele wrote:
Ideally each session would work more or less as follows:
do (hdl,hn,pn) <- accept socket text <- hGetContents hdl inputs <- parse text replies <- sequence $ map reply inputs sequence $ map (hPrint hdl) replies ...
Where parse and reply are IO functions that produce and consume some kind of higher level representation of the text that the client sent. Of course this won't work because the code will first try to read all the input and then to write back all the replies. I think that if I had two different handles for input and output I wouldn't have this problem, am I right ? Is there a way to handle such situation without having to read the input text in chunks ? This for example would allow me to use a library like Parsec to parse the input (that looks like works on string and not on handles)
It looks like the lazy read problem rears its ugly head again. =) Try the following: do (hdl,hn,pn) <- accept socket text <- hGetContents hdl if text == text then return () else return () inputs <- parse text replies <- sequence $ map reply inputs sequence $ map (hPrint hdl) replies ... The conditional will force 'text' to be read in full, which will free the handle for writing. /Niklas _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963