Re: String literal as template parameter?

On Apr 13, 4:09 am, Piotr Rak <piotr....@[EMAIL PROTECTED]
> wrote:
> Hi all,
>
> I was thinking about language feature allowing convert string literal
> into variadic character pack (char...).
>
> Here is real life use case, which comes from Yard parser library
> (http://yard-parser.sourceforge.net/cgi-bin/index.cgi).
> It shall define parser that matches sequence of characters.
> Exact implementation doesn't matter.
>
> It has been slightly modified to use variadic templates
>
> template <char Char1_, char Char2_, char...MoreChars_>
> class CharSeq
> {
>     static const unsigned int length = sizeof...(MoreChars_) + 2;
>
>     inline static char get_nth(unsigned int n);
>
> public:
>     template <typename ParserState_>
>     static bool match(ParserState_& state);
>
> };
>
> typedef CharSeq<'c', 'a', 't', 'c', 'h'> CatchKeyword;
> // which could be:
> //typedef CharSeq<"catch"> CatchKeyword;
>
> There is proposal of 'User-defined literals' (http://www.open-std.org/
> jtc1/sc22/wg21/docs/papers/2007/n2378.pdf), but atleast in my
> understanding, it fails to provide way of doing that.
>
> Is my assumption is correct?
> If yes, what are technical reasons from preventing that?
>
> Cheers, Piotr Rak

the current standard does not sup****t Variadic Templates they may be
added in the c++ox revision
i do not think any c++ compilers other than gcc sup****t this
http://www.osl.iu.edu/~dgregor/cpp/variadic-templates.html
so i fyou do wnat ****table code or are using som other compiler you
would need to declare
your class templates with the required number of template parameters.

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