Re: [boost] [xpressive] semantic actions: is ref() necessary

From: Eric Niebler (eric_at_[hidden])
Date: 2008-02-06 11:34:35

Thorsten Ottosen wrote:
> 
> Ok, but let me make the question more specific: why would you ever pass
> a container by value to push_back()?

Of course you wouldn't, but the first argument to push_back() may not, 
in fact, be a container. It may be an expression template that evaluates 
to a container.

I could consider making push_back() "smart" and check whether its first 
argument is an expression template, or a terminal, or what, and assume 
any type it doesn't know about is a container that should be stored by 
reference, but this makes me uncomfortable. Now push_back() is special, 
and special cases makes things harder to learn.

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