[Haskell-cafe] Re: Network parsing and parsec

John Goerzen writes:

With networking, you must be careful not to attempt to read more data than the server hands back, or else you'll block. [...] With a protocol such as IMAP, there is no way to know until a server response is being parsed, how many lines (or bytes) of data to read.

The approach I recommend is to run a scanner (tokenizer) before the actual parser. IMAP, like most other RFC protocols, is line-based; so you can use a very simple scanner to read a CRLF-terminated line efficiently (using non-blocking I/O, for example), which you can then feed into the parser just fine because you know that it has to contain a complete request (response) that you can handle. Peter