Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uunet!brunix!sdm
From: sdm@cs.brown.edu (Scott Meyers)
Newsgroups: comp.lang.c++
Subject: Multiple parsers in C++?
Message-ID: <69907@brunix.UUCP>
Date: 26 Mar 91 22:02:45 GMT
Sender: news@brunix.UUCP
Reply-To: sdm@cs.brown.edu (Scott Meyers)
Organization: Brown University Department of Computer Science
Lines: 27

I'm writing an application that needs to use multiple lexers and parsers.
The ideal situation would be to use modified versions of lex and yacc so
that each lexer/parser was in its own class.  This is sort of done by
bison++, but it currently generates code that won't compile under anything
but g++ (it initializes data members inside the class declaration).  In
addition, there is no corresponding flex++, at least not that I know about,
so you're still stuck with a single lexer unless you go in and change
things by hand.  I also know about lex++/yacc++ that come with the Sun
compiler, but the (beta) versions that we have don't seem to generate
classes, i.e., they're just lex and yacc that generate C++ instead of C
(with no gain in flexibility).

What I want to be able to do is have files lexer1.l and parser1.y run
through a lex++/yacc++ yielding class parser1, which would have member
functions yylex and yyparse, while the files lexer2.l and parser2.y would
yield class parser2 with the same member function names.  Furthermore, I
want to be able to set up a makefile so the generation of these classes is
automatic -- I don't want to tweak things later by hand.  My source files
are the .l and .y files, and I really would like to keep it that way.

I hope I'm overlooking some obvious solution, and I'm hoping somebody will
tell me what it is.

Scott

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