Re: [Boost-users] Using boost::lambda::bind with std::transform

From: Kobi Cohen-Arazi (kobi.cohenarazi_at_[hidden])
Date: 2006-04-27 12:52:37

Hi Sebastian,

You are 100% right.
The return by reference is wrong. and the removeConst is absolutely not
needed. It works just fine without. And I understand why adding & to the
std::string is wrong.

So just a quick recap, to see if we have 100% of the solution:
There is no way to use directly the std::string::replace since get() is
const member function.
We do need a replace wrapper, which unfortunately creating std::string
instances.

Am I right here?

Thanks for your help!
Kobi.

On 4/27/06, Sebastian Redl <sebastian.redl_at_[hidden]> wrote:
>
> Kobi Cohen-Arazi wrote:
>
> > Will not work !
> > Why adding the & hurts?
> > Kobi.
>
> Because you attempt to bind a non-const reference to a temporary object
> (the return value of get(). The compiler refuses to do that.
> The compiler doesn't catch another possibly problematic situation,
> though, and that's replace's return by reference. You're returning a
> reference to a function parameter, and that's generally not a good idea.
>
> On the other hand, the removeConst function does absolutely nothing in
> your program except create yet another copy of the string. get() already
> returns a copy. The function is const, but its return value is not a
> const reference.
>
> Sebastian Redl
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