Suggestion: Enrich the format API by exposing some elements of details

[lano1106]

I wanted to support some sort of precision specifications without reinventing the wheel for my user defined formatter...

After having opened the hood to see how you were doing it. I ended up with:

    constexpr auto parse(ParseContext& ctx) -> decltype(ctx.begin())
    {
        auto it = ctx.begin(), end = ctx.end();

        if (it != end) {
            if (*it == 'm') {
                m_type = MAXIMUM;
                ++it;
            } else if (*it == '.') {
                m_type = CUSTOM;
                it = detail::parse_precision(it, end, Handler<ParseContext>{ctx, m_specs});
                if (it == end) return it;
            }
        }
        // Check if reached the end of the range:
        if (it != end && *it != '}') throw format_error("invalid format");
        // Return an iterator past the end of the parsed range:
        return it;
    }

I am pretty sure that a lot of people would appreciate if detail::parse_precision() and others would be easily available to them...

[vitaut]

Thanks for the suggestion. This and related documentation improvements are already tracked in #2086 and will hopefully be addressed in one of the upcoming versions.