Re: [boost] Bounded types (or maybe not 'bounded' anymore? ;-)

From: Robert Kawulak (kawulak_at_[hidden])
Date: 2005-09-29 13:54:46

Hi, 

> From: Ben Artin
> 
> In article <BAY104-DAV1150B74243DE0C91E6C3DDBF8C0_at_phx.gbl>,
>  Daryle Walker <darylew_at_[hidden]> wrote:
> 
> > Actually, under my opinion/theory, NO function, member 
> function, or operator
> > returns a const non-reference.  That's includes the 
> post-increment operator.
> > However, I don't have the "Exceptional C++" book, so I 
> don't know the
> > author's reasoning for his opinion.
> 
> Implement a post-increment that returns a non-const, then see 
> what x++++ does, 
> and you'll understand the reasoning :-)

This is the reasoning shown in "Exceptional C++" - the point is that UDTs'
behaviour should be similar to built-in types whenever possible. You can't
do x++++ with int, so you shouldn't be able to do this with UDTs either.

Recently I found another good reason to return const value -
bounds-specifier policy class contains two functions: min_value() and
max_value(). These values are constant by nature (they don't change during
execution of a program), so it's natural to return them as consts. This may
help finding bugs, because it's not very likely that someone would want to
modify on purpose the value returned from one of these functions - would it
make any sence?

Best regards,
Robert