Re: [Boost-users] [Proto] Recreating an expression

Subject: Re: [Boost-users] [Proto] Recreating an expression
From: joel (joel.falcou_at_[hidden])
Date: 2009-07-01 16:50:33

christophe henry wrote:
> Hi to all proto experts,
>  
> I have a grammar whose only goal is to build a type:
> template <class Expr> struct ActionBuilder with an operator() which 
> simply calls:
> proto::eval(Expr(),my_context);
> Unfortunately, I have an expression like:
> boost::proto::exprns_::expr<boost::proto::tag::plus,boost::proto::argsns_::list2<const 
> A&,const B&> >
> And the compiler is unhappy about finding no appropriate default 
> constructor (I suppose because of the references).
> deep_copy is probably not usable inside a grammar definition, so is 
> there an easy way of getting rid of the references (if they are really 
> the problem) or do I have to go and get my MPL canon?
> I am really just interested in having the recreated expression use a 
> new instance of A and B, not the original ones.
I see nothing special about this expression. Can you giv soem more code 
and a call example.

-- 
___________________________________________
Joel Falcou - Assistant Professor
PARALL Team - LRI - Universite Paris Sud XI
Tel : [phone]