Re: Spirit - rule generating functions

From: Vaclav Vesely (yg-boost-users_at_[hidden])
Date: 2003-04-06 16:06:55

Joel de Guzman wrote:
...
> Actually, Spirit v1.5.1 rules can be stored as you've tried to do.
Unfortunately,
> the C++ copy/assignment semantics differ too much from EBNF that
> when I tried to merge a hybrid, people complained and it caused lots of
> confusion (see the Boost Spirit review sometime in October 2002).
...

I don't claim the following is the only truth. It's just my subjective point
of view.

IMO the C++ copy/assigment semantics is very importent. A breach of this
semantics is much more confusing than the need of "r = rr.alias();"

Even if the former beaviour was not suitable, I wouldn't abolish the
copy/assigment semantics. Instead of it I would change the way of setting
rules in this way:

    r.reset(a >> b);
    r.reset(rr);

So this
    r = rr;
would lead to sharing definition and this
    r = a >> b;
would be an error.

As I said, this is only my point of view. I will be glad to confront it with
any other.

Regards,
w