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From: jimad@microsoft.UUCP (Jim ADCOCK)
Newsgroups: comp.lang.c++
Subject: Re: C++ Grammar
Message-ID: <70872@microsoft.UUCP>
Date: 25 Feb 91 18:56:56 GMT
References: <3786@lupine.NCD.COM> <1991Feb08.130548.6878@iti.com> <70609@microsoft.UUCP> <112@shasta.Stanford.EDU>
Reply-To: jimad@microsoft.UUCP (Jim ADCOCK)
Organization: Microsoft Corp., Redmond WA
Lines: 20

In article <112@shasta.Stanford.EDU> shap@shasta.Stanford.EDU (shap) writes:

|The problem with Roskind's grammar (at least the last time I looked - it
|may have been updated in the past few months) is that it requires the
|lexer to resolve "typedef" v/s "identifier", which is probably the most
|difficult problem in the language as far as parsing goes.  If anyone has
|built a tool that overcomes this limitation, including the associated
|symtab support, I would be interested to see it.

Huh?  As far as I can see, the need for the lexer feedback hack is 
central to any C/C++ parser using a lex/yacc like approach.  The need
for the hack is implicit in the C/C++ language's permission of allowing
typedef to define new types, that then can be used in the future without
a "struct", "class", "union", or "type" keyword as one would find in other
languages that allows differentiation the typedef word from identifiers.
I don't see this as a restriction in Roskind's approach.  I see it as a 
central requirement of C/C++ parsing because of "typedefs."  All lex/yacc -
like approaches that I have seen use this hack.

How else would you do it?