Re: [boost] Formal Review Request: Boost.String.Convert

Subject: Re: [boost] Formal Review Request: Boost.String.Convert
From: David Abrahams (dave_at_[hidden])
Date: 2009-02-18 12:21:12

on Wed Feb 18 2009, "Vladimir Batov" <batov-AT-people.net.au> wrote:

>>>     convert::to<wstring>
>>
>> Why not just convert_to<wstring>?
>>
>> Is the problem with convert by itself that it leaves the reader worrying
>> about 'to' and/or 'from'?
>>
>> - leaving one feeling 'what?'
>>
>> Direction matters.
>
> Yes, once I got comfortable with boost::convert::to I realized that after
> generalization the 'from' is obviously redundant as string-from-int can always be
> transformed to int-to-string. So, 'from' died out. When only 'to' left, I asked myself
> what it was doing on its own.
>
> I do agree in principle that having direction helps (even only somewhat) but 'to' does
> not seem to work. It all starts nicely:
>
>    string s = boost::convert::to<int>(-1)
>
> Above 'to' does seem natural (IMHO of course) as the line kind of reads as "convert to
> int". However, with the default parameter it becomes
>
>    string s = boost::convert::to(-1, "failed to convert")
>
> i.e. 'to' becomes a nuisance. 

Not just a nuisance; it reads incorrectly, as "convert to -1."
I think it would be better to always require the destination type, so:

   boost::convert::to<string>(-1, "not convertible");

and

   using boost::convert::to;
   to<string>(-1, "not convertible);

looks good, too.  If you want a name without angle brackets,

  boost::convert::to_string(-1, "not convertible");

works for me.  

Hmm, how do I convert to a hex string?

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com