Re: [boost] Static constexpr map (was: Re: [gsoc16] Can I quickly check if the below really is the best approach?)

On 14 January 2016 at 22:41, Marshall Clow wrote:

On Wed, Jan 13, 2016 at 11:43 AM, Niall Douglas

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wrote:

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Sadly, the current proposal for string_view does not provide a default Traits length function which is constexpr for const char *. Yes, I find that very daft as a default design choice for a string_view, but the macro at least makes it not too irritating.

It uses the existing char_traits classes, which, as you note, are not constexpr. (for some *very odd* reasons).

But writing your own traits class that has constexpr len/compare/etc is really, really simple. Maybe I'll do that this weekend, and add it to boost. :-)

Because it gets passed in as a template parameter, it isn't really all that general a solution, as it makes your string and string_view types different than std::string and std::experimental_string_view. If it is only used for initializing the static_map, that would probably be fine, but if it appears anywhere else in the interface, it just makes the static_map harder to use. You really want static_map to just work so that you can do runtime lookups using C string literals and std:string directly. -- Nevin ":-)" Liber > +1-847-691-1404