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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: C/C++ knocks the ....
Date: 1996/02/24
Message-ID: <Dn97IA.Az0@world.std.com>#1/1
X-Deja-AN: 140857882
references: <4g2r2r$ded@stc06.ctd.ornl.gov> <milodDn4y3q.Kz4@netcom.com>
 <Dn8JxK.MGK@world.std.com> <EACHUS.96Feb23182705@spectre.mitre.org>
organization: The World Public Access UNIX, Brookline, MA
newsgroups: comp.lang.ada
Date: 1996-02-24T00:00:00+00:00
List-Id: <comp.lang.ada>

In article <EACHUS.96Feb23182705@spectre.mitre.org>,
Robert I. Eachus <eachus@spectre.mitre.org> wrote:
>...When the syntax was first
>changed to use the ' for qualified expressions, there
>were cases where you had to do arbitrary lookahead
>to determine whether or not the first ' started a character literal or
>an attribute. A'B'('"','A','B','C',... is the canononical "horrible"
>case.

I don't understand your example.  The technique I'm familiar with is to
use look-back, not look-ahead.  E.g. if the previous token is an
identifier, and there's an apostrophe after it, it cannot possibly be
the start of a character literal.  If you look at all the syntax rules,
you can figure out, for each token, whether it can be followed by a
character literal or not.

Are you saying that B is (or might be) an attribute name in the above?
Were there user-defined attributes in Green?

- Bob