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

Subject: Re: [boost] Formal Review Request: Boost.Convert
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2009-02-19 08:42:59

On Thursday, February 19, 2009 2:57 AM
Vladimir Batov wrote:
>
> namespace boost
> {
>     template<class TypeIn, class TypeOut, class Enable =void>
> class convert;

s/convert/converter/

      // leave default value computation to converter
      template <class TypeOut, class TypeIn>
      TypeOut const
      convert(TypeIn _input)
      {
         return converter<TypeIn,TypeOut>(_input);
      }

      template <class TypeOut, class TypeIn>
      TypeOut const
      convert(TypeIn _input, TypeOut const & _default)
      {
         return converter<TypeIn,TypeOut>(_input, _default);
      }
> }
[snip class template declaration]

> int string_to_int = convert<string, int>(str, -1);

   int s2i(convert<int>(str, -1));

> int string_to_int = convert<string, int>(str);

   s2i = convert<int>(str);

> convert<string, int> string_to_int(str, -1);

   converter<string,int> c(str, -1);

> convert<string, int> string_to_int = convert<string, int>(str, -1);

   c = convert<int>(str, -1);

> std::transform(
>         integers.begin(),
>         integer.end(),
>         std::back_inserter(strings),
>         convert<string, int>::apply);

s/convert/converter/

> As you can see there is *no* type-deducing. That is, with
> that approach
> we'll have to always indicate 'to' and 'from' types. That
> seems verbose...
> but might be a plus as it takes *any* ambiguity out.

As you can see, there is type deduction.  That is, with this approach, we won't need to indicate the source and destination types in all contexts, but can when needed to remove ambiguity.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer, Core Software      using std::disclaimer;
Susquehanna International Group, LLP  http://www.sig.com

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