From: Petr Kocmid (pkocmid_at_[hidden])
Date: 2002-10-22 23:16:48
> Perhaps ~ch_p('x') and ~digit_p will both result to a chset as well.
> However, there's a problem. Character sets can support 8/16/32
> bits. While it is clear that ~ch_p('x') is chset<char> with everything
> on except 'x', and ~ch_p(L'x') will be chset<wchar_t>, what will be
> the type of ~digit_p? Shall it be hardcoded to chset<char>?
Perhaps using a chset seems to be a little overkill in certain cases.
I have this idea, resulted from closer look in primitives.hpp: for all single character parsers which are using locale-style check call in their test function, the most efficient way to make a complementar parser would be to add a completely new little parser, such as not_digit_p, having return !impl::isdigit_ in underlying test().
Then ~digit_p could map to not_digit_p and vice versa, making such complement operation naturally symmetric. And honoring locale, too. More, no need to hardcode anything to chset<char>.
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