Re: [boost] [proto] small breaking change

Subject: Re: [boost] [proto] small breaking change
From: Joel Falcou (joel.falcou_at_[hidden])
Date: 2010-06-11 01:57:52

Eric Niebler wrote:

> It should be fixed now. Give it a shot. 
Fixed indeed.

> Just curious, what does your custom generator do?

Given a proto expression X, it builds a
table_expr< typename proto::tag_of<X>::type, X>

basically I add the tag of the expression in the expression wrapper
type. Sounds silly but later, we need to know if a given expression
is of tag A or B and doing so cut a lot of compile time compared to 
calling tag_of each time. It also allow us to overload table_expr
behavior based on tag without relying on the internal type of proto 
expression, making it easy for developper to add such special behavior
on some non-trivial expression node.