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From: lma@Neon.Stanford.EDU (Larry M. Augustin)
Newsgroups: comp.lang.c++,gnu.g++
Subject: Re: yacc/lex experience...
Message-ID: <1990Aug7.025211.14584@Neon.Stanford.EDU>
Date: 7 Aug 90 02:52:11 GMT
References: <3006@zipeecs.umich.edu> <4049@czech.sw.mcc.com>
Organization: Computer Science Department, Stanford University
Lines: 30

In article <4049@czech.sw.mcc.com> krohn@czech.sw.mcc.com (Eric Krohn) writes:
>In article <3006@zipeecs.umich.edu> bagchi@dip.eecs.umich.edu (Ranjan Bagchi) writes:
>]     Does anyone have any experience with using yacc & lex in
>] conjunction with c++/g++?  I've got a yyparse function which I would
>] like to make a member function of class say...foo.  
>]     I'm assuming that everything could be done with a sed script, but
>] I really don't know about all the functions which need name-changes.
>
>I have turned yyparse into a member function for two different programs.
>Among the advantages are turning the global variables used to communicate
>with yyparse into member variables, and access to members variables and
>functions within the yacc actions.  With a little doctoring of the y.tab.c,
>you can have multiple coexisting parsers, each within its own class.
>
>The definition of yyparse must have its name changed to member function
>syntax (Parser::yyparse, for example).  It is wise to make yychar,
>yylval, yydebug, yylex(), and yyerror() into member variables/functions
>also.  Have your sed (or perl) script delete the global
>definitions/forward declarations of yychar, yylval, yyparse, yydebug,
>and yyerrflag.  If you want multiple parsers, or if you like data
>hiding, make all the other global yy* names static.

I have a version of bison (I call it bison++) that I hacked up some
time ago to generate a parser class in this vein.  It's available via
anonymous ftp on wilbur.stanford.edu.

Larry M. Augustin			ERL 414
lma@sierra.stanford.edu			Computer Systems Lab
lma@dayton.stanford.edu			Stanford University
(415) 723-9285				Stanford, CA 94305