Proto for Boost mailing list page: Re: [proto] Refining the Proto concepts

Subject: Re: [proto] Refining the Proto concepts
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2012-07-18 18:59:47

On 18/07/2012 18:29, Eric Niebler wrote:

> Is there some code in Proto that is forcing the instantiation of those
> specializations? Probably, and that would unintended. One approach would
> be to replace these normalized forms with an equivalent incomplete type
> and fix all places where the code breaks.

Doesn't

template<class T>
struct foo
{
    typedef bar<T> baz;
};

foo<int> f = {};

instantiate bar<T>?

The problem I see is that for a regular Proto expression, the whole tree 
gets instantiated twice for expr and basic_expr.