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From: | Daniel Kraft |
Subject: | Re: Parsing from continuous stream |
Date: | Sun, 20 Jan 2008 09:48:11 +0000 |
User-agent: | Thunderbird 2.0.0.0 (X11/20070425) |
I'm trying to use GNU bison to parse from a "continuous" stream, that is, I do want to implement a program similar to a shell: parse one "command" at a time, process it, and continue until end-of-stream is encountered.However, I do want my parser to return the parsed tree to the calling program to process it on each step, so ideally I'd like bison to return from yyparse() when a complete instance of the start symbol is read, but it seems it does not do this (waits for special 0-token, as far as I found out)--to counter-act, I currently do something like this:start_symbol: real_start_symbol { storeValueForProcession($1); YYACCEPT; } ;Aha, Yes! Use the push parser that I have just implemented in Bison. You will be the first beta tester. The documentation should be in CVS and you need a CVS version of bison.
Thanks for the hint, it looks neat as far as I have seen yet! But I'm not yet sure how this will help me exactly; will yypush_parse return without this YYPUSHMORE whenever it encounters the start symbol (or any symbol?), so I can process it in my code and continue calling yypush_parse afterwards, with the state including all look-ahead conserved?
BTW, how does one bootstrap the autotools stuff for bison? Trying myself with aclocal; automake -a; autoheader; autoconf (like this) gives me errors in the resulting configure related to gl_* symbols; I suspect that autoconf is missing some m4-files or the like?
Cheers, Daniel -- Got two Dear-Daniel-Instant Messages by MSN, associate ICQ with stress--so please use good, old E-MAIL!
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