Re: [boost] Boost.Convert. Take 2.

Subject: Re: [boost] Boost.Convert. Take 2.
From: Vladimir Batov (Vladimir.Batov_at_[hidden])
Date: 2014-02-16 15:56:47

Addressed all three comments... I think. Checked in.

On 02/16/2014 02:58 AM, Edward Diener wrote:
> On 2/14/2014 2:16 PM, Vladimir Batov wrote:
>> On 02/15/2014 01:46 AM, Edward Diener wrote:
>>> On 2/13/2014 11:01 PM, Vladimir Batov wrote:
>>>> ...
>>>> Finished the docs. The whole thing is at
>>>> https://github.com/yet-another-user/boost.xtra.
>>>
>>> Is the library called "xtra" or "convert" ?
>> The library si still called the same "convert". Housed it in the
>> "boost.xtra" dir to distinguish it from the real boost dir.
>>>
>>> The library should be in modular-boost structure. You have it in the
>>> old SVN structure.
>> OK. I'll look into it.
>>>
>>> Running b2 in the doc directory gives all sorts of errors because you
>>> are still using the old SVN structure. So it is impossible to see the
>>> documentation.
>>
>> Yes, did not check all (duh!) docs yesterday. Fixed now.
>
> These lines in the doc look wrong. The expression 'convert<int>result' 
> does not look possible in C++. I think this should be 
> 'convert<int>::result'.
>
> convert<int>result r1 = boost::convert<int>(str1, cnv); // Does not 
> throw on conversion failure
> convert<int>result r2 = boost::convert<int>(str2, cnv); // Does not 
> throw on conversion failure
>
> I think you need to be precise in what a user-defined type needs to 
> provide in order to be 'convertible from' and 'convertible to' within 
> the convert framework. If that is too complicated in a design as a 
> general form of using convert, then limit the library to conversion 
> either to and from a std::basic_string<T> and specify what the single 
> type being converted from or to a std::basic_string<T> needs to supply 
> in order to work with convert. I actually see nothing wrong with such 
> a limitation if it is necessary to accomplish more easily what you 
> envision. I did not understand this information from the docs. Perhaps 
> you have worked this out but you need to explain it quite methodically.
>
> I would also suggest that callables ( std::function types ) be used 
> instead of hardcoded function names when supplying user-defined 
> conversion functionality. This provides a much more flexible ability 
> to provide conversion for a user-defined type since the full retinue 
> of functor creation within the standard C++ library and from within 
> Boost can be used by the end-user to provide appropriate conversion 
> routines. Once you hardcode some conversion member function within a 
> class you are throwing out all this functor creation ability. Of 
> course if such a design is too complicated based on your own design 
> for convert then stay with what you currently have, but at least 
> consider it if you understand the power of C++ callables to provide 
> user-defined functionality.