A while ago I started writing an HTTP library and I have been trying to decide how to write it. Let me explain…
If I wanted to use DCG notation then, as far as I understand the mechanics of gprolog, I would need the complete list in its entirety to begin with which means that I would need to keep on reading bytes from the socket connection until …. when? I couldn’t assume that a socket close would indicate the end of the request in case ‘keep-alive’ had been sent in the header! The implication is that I would therefore have to write a parser that fetched one character at a time and using the usual methods (FSM-s etc) gradually work its way through the stream examining each part of the request as it was received and then taking the appropriate action. That is also not a problem, I have already written such a parser for a computer language I developed a while back which parses S-expression syntax into a list of terms so that is not a problem either should I choose to go down that route. Is there scope within the “[]” operator to extend it to consume data from a stream ? Tonight I will do some research on this but is it even possible withing GNU Prolog, I don’t know yet?!?!?! What I would like to try to achieve is some sort of system whereby a modified DCG translation system would “fault” on having the empty list and before continuing, attempt to read another character from the stream, and only truly “be” the empty list of the EOF has been reached. I think that this also raises issues though because this would have to be buried from the actual point of trying to unify the DCG head if you see what I mean. Sometimes being igorant is hard work! Thanks in advanc elist for any useful feedback. _______________________________________________ Users-prolog mailing list Users-prolog@gnu.org https://lists.gnu.org/mailman/listinfo/users-prolog
