[Please keep the Help-Bison cc, so that others can help.]
At 13:28 +0200 2005/05/08, Carsten Krüger wrote:
HA> I recall Paul Eggert said that the Bison generated parser, which he HA> wrote, now is fully pure.
Which parser?
The C-parser skeleton file. But your subsequent explanations suggests that this is not a question for Paul (sorry).
HA> If you have some data to be passed to the HA> parser, that should be done via the arguments to yyparse, and there HA> are some macros for doing that; see the Bison manual. If yyparse HA> needs some local data, then there might not be support for doing that HA> right now. Then you need to figure out how to make the Flex generated HA> lexer to become pure; for that, check in the Help-Flex list HA> <help-flex@gnu.org>.
Can you explain it a litte bit more?
I do not use a fully pure parser, and I use a C++ parser. So you will have to hope from more input from somebody else.
I try to explain my problem.
My bison grammar has a BEGIN and an END token and I want to parse many inputfiles consecutively.
Example.
file1: START some command ... STOP
file2: START some command ... STOP
Then you do not need fully pure parser.
If I use only: yyin=fptr_1; yyparse(); yyin=fptr_2; yyparse();
The second yyparse()-call tells me, START is unexpected. The parser don't know, that the inputfile has changed. This might be usefull for include-files in C, I think.
Most likely, this is a problem that the lexer has not been reset. Read the Flex manual, or ask in the Help-Flex list. I use something like "lexer_.initialize(isp_)", but I do not know if that is the original Flex lexer function. The parser function yyparse() will be reset every time it is called anew. It only parses tokens, not streams.
--
Hans Aberg
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