Re: [boost] Yacc, lex, and C++

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2002-02-26 16:13:14

----- Original Message -----
From: "Rainer Deyke" <root_at_[hidden]>

> ----- Original Message -----
> From: "Kevin S. Van Horn" <kevin.vanhorn_at_[hidden]>
>
> > David Abrahams writes:
> >
> > > Most good C++ parsers use recursive descent, as I understand it.
> >
> > I don't think so.  A recursive descent parser has to be
> nondeterministic
> > -- and hence do LOTS of backtracking -- in order to parse
> expressions
> > involving infix operators.
>
> I don't think so.  It's really quite trivial for a handwritten
> recursive descent parser to parse infix expressions with no
> backtracking and single token lookahead:

Oh, yeah, what is Kevin talking about? I would never have said "compiler
writers know this" about infix expressions with RD parsing, since I've
written several of these myself. There are expressiveness issues with LR
grammars, but this ain't one of them.

-Dave