Proto for Boost mailing list page: Re: [proto] Expression as *other* fusion sequence

Subject: Re: [proto] Expression as *other* fusion sequence
From: Joel falcou (joel.falcou_at_[hidden])
Date: 2011-06-17 07:46:31

On 17/06/11 01:25, Eric Niebler wrote:
> Doable, but not easy. The problem you'll have is that all Proto
> expression types have a nested fusion_tag that is a typedef for
> proto::tag::proto_expr. That is how Fusion figures out how to iterate
> over Proto expressions. You'll need to define your own tag, use
> proto::extends (not BOOST_PROTO_EXTENDS) to define an expression
> extension, and hide the fusion_tag typedef in the base with your own.
> Then you'll need to implement the necessary Fusion hooks for your custom
> Fusion tag type.

OK, but is there any internal proto part relying on the proper fusion 
behavior that may get hampered by this ?

I'll give it a try :)