🚀 go-pugleaf

Hi!
   I'm trying to write a pure (re-entrant) parser using flex and
bison.  In the bison manual, it tells me I can use '%pure_parser' to
do this, and I also need to redeclare yylex like this:

    yylex(lvalp, llocp)
        YYSTYPE *lvalp;
	YYLTYPE *llocp;

    This is so bison doesn't have to use the global variables that it
normally uses to get info from yylex.

    The flex documents tell me that I can re-declare yylex in this
manner if I use :

    #define YY_DECL int yylex(lvalp, llocp) YYSTYPE *lvalp; YYLTYPE *llocp;

    My problem is that yylex doesn't appear to know what YYLTYPE is.
Is this the starndard way to make a re-entrant parser using flex and
bison, or is it only used when you are writing your own parser?
    I figured that this would work by overshadowing the global
declarations of lvalp and llocp with these local ones.  However, when
I searched lex.yy.c, I found no declarations of lvalp or llocp.
Neither did I find declarations for the global variables that bison
says it uses, yylval and yylloc.  I even looked for an include file
that either might use that defines either of these, and I can't find it.
    I'm thinking that I might be able to overcome my problems if I
changed YY_INPUT so that it only reads one character at a time.  This
might solve my problem, as I am implementing an interpreter that
changes input files, and I find that there is stuff from the first
file still in the buffer when I change to the second file.  In a truly
re-entrant parser, this wouldn't be a problem, would it?
    The flex document also suggests that lex might be a better choice
for a re-entrant parser.
    Any suggestions?



--
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James A. Ertle, University of Vermont, Burington, Vermont, USA
send mail to: ertle@kira.uvm.edu
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