From: Yuval Ronen (ronen_yuval_at_[hidden])
Date: 2005-01-30 16:20:41
> Come to think of it, it can be done simpler and clearer, and avoiding any
> extra includes, like this:
>
> namespace detail
> {
> template<class T>
> struct array_to_pointer_decay
> {
> typedef T type;
> };
>
> template<class T, size_t N>
> struct array_to_pointer_decay<T[N]>
> {
> typedef const T * type;
> };
> }
>
> template<typename Target, typename Source>
> Target lexical_cast(const Source &arg)
> {
> typedef typename detail::array_to_pointer_decay<Source>::type
> NewSource;
>
> detail::lexical_stream<Target, NewSource> interpreter;
> Target result;
>
> if(!(interpreter << arg && interpreter >> result))
> throw_exception(bad_lexical_cast(typeid(NewSource),
> typeid(Target)));
> return result;
> }
I haven't tried it, but I have a feeling that it will work for string
literals, but not for c-string variables, so another specialization
might be needed. But it shouldn't be too hard to add, so no real problem
here. Or maybe c-string variables aren't supposed to be supported anyway?
> This requires support for partial specialisation, but so does remove_bounds
> used in the first suggestion, so it doesn't change the compiler
> requirements. Besides, the current version of lexical_cast in CVS doesn't
> work with MSVC 6, anyway. Of course, if this was very important, I guess it
> would be possible to fall back to pass by value for MSVC 6, and possibly fix
> other problems with it. I also see that MSVC 6 is no longer part of the
> Boost regression test.
Do you mean that boost has finally dropped support for MSVC 6?
Congratulations, it's about time... :-) Anyway, the above solution looks
excellent to me.