On 2005-09-15, Peter Simons
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.
I thought of that, but that isn't really true for IMAP. IMAP responses can span many, many lines (for instance, it can return a list of all matching messages in a folder, or multiple bits of status results). Or they can use only one line. Not only that, but IMAP has a way where you can embed, say {305} instead of a string. That means, "after you finish reading this line, read exactly 305 bytes, and consider that to be used here." But if you see "{305}" (the double quotes indicating a string), this is just a string containing the text {305}. So, to make that approach work, I would really need to do a lot of work outside of Parsec -- the stuff that I really want to use Parsec for, I think. -- John