[boost] Re: [spirit] rule<> and copying

From: Eric Niebler (eric_at_[hidden])
Date: 2004-06-07 16:14:22

David Abrahams wrote:
> "Eric Niebler" <eric_at_[hidden]> writes:
> 
> 
>>I have a new idea. Deep copy can be triggered by assigning to a dummy
>>member:
>>
>>rule<> a, b;
>>a.rule = parser >> that >> refers >> to >> b;
>>b.rule = parser >> that >> refers >> to >> a;
>>
>>This allows:
>>a = b; // shallow copy, creates alias
>>a.rule = b.rule; // deep copy, modifies 'a' and all its aliases
>>
>>xpressive now works this way. It's heavier syntactically, but far less
>>confusing then using a special deep-assign operator.
> 
> 
> I think
> 
>   a->rule = b->rule
> 
> would be much more consistent with the other semantics of this thing.
> 

<nods> Much better. I like.

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com