From: Marc Mutz (marc_at_[hidden])
Date: 2006-07-03 03:03:02
On Monday 03 July 2006 00:14, Jeff Garland wrote:
> I assume you meant
> s = s.trim();
After renaming trim_copy(), yes. Otherwise no.
> Well, that's very persuasive although I think it's harder to write
> something modifies a collection of objects in place -- no?
Very good point. With a mutating trim(), people are tempted to write
std::for_each( v.begin(), v.end(), mem_fn( &super_string::trim ) );
which, strictly speaking, is not explicitly allowed by the std, IIRC. With a
const trimmed(), the user would be forced to use
which much better conveys what the code does.
> Don't get me
> wrong, I'm pretty fond of immutable value types. Most of date_time is
> written as immutable value types with a couple exceptions. However, in
> this case I'm building on a base type that's already mutable and it seems
> to me that it's pretty natural to say s.replace_all(...).
It's only natural b/c it's what people are used to. It's much easier, IMHO, to
work with immutable types, b/c the interface is consistent. You have a point
when you say that std::string is a mutable type and you're building on it.
That doesn't mean, however, that you need to keep it's baggage. :)
-- Marc Mutz -- marc_at_[hidden], mutz_at_[hidden] phone: +49 521 521 45 45; mobile: +47 45 27 38 95 Klarälvdalens Datakonsult AB, Platform-independent software solutions
Boost list run by bdawes at acm.org, david.abrahams at rcn.com, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk