On Thu, Apr 23, 2020 at 8:30 AM G. P. B. <george.bany...@gmail.com> wrote:
> On Wed, 22 Apr 2020 at 15:25, Nikita Popov <nikita....@gmail.com> wrote: > >> Hi internals, >> >> I'd like to make two improvements to the printf() functionality exposed by >> PHP (also affecting other variations like sprintf, vprintf, etc.) These >> improvements are motivated by >> https://wiki.php.net/rfc/locale_independent_float_to_string, which will >> make float to string casts locale insensitive, but not change the behavior >> of printf() specifiers. >> >> The proposed improvements are: >> >> 1. Support for the %h and %H specifiers, which behave the same as %g and >> %G, but are locale insensitive. These specifiers are already supported >> internally in PHP (though %h goes by the name of %k for reasons that are >> not relevant to userland) and is used for formatting floating-point >> numbers >> where case-sensitivity is not desired, such as for var_export(). >> >> 2. Support for * width and precision, in which case the width/precision is >> provided as an argument to printf(). This is a feature of printf() in C. >> >> The combination of these two features allows us to easily print floating >> point numbers exactly as PHP would print them: >> >> // Locale-sensitive using precision ini setting. >> sprintf("%.*G", ini_get('precision'), $float); >> >> // Locale-insensitive using serialize_precision ini setting. >> sprintf("%.*H", ini_get('serialize_precision'), $float); >> >> Notably, this also supports precision -1 (the default >> serialize_precision), >> which will pick the shortest accurate representation of the float. >> >> Without these features, it is actually quite hard to replicate PHP's exact >> behavior. The best approximation I've found is to print with %G at >> multiple >> precisions, pick out the shorted one and replace commas with dots on the >> assumption that comma is the only locale-specific decimal separator. It >> would be good to expose what PHP can already do directly. >> >> Implementations for the two features are available at >> https://github.com/php/php-src/pull/5432 and >> https://github.com/php/php-src/pull/5436. >> >> Regards, >> Nikita >> > > Seems like a no-brainer to add on my side. > > Best regards > > George P. Banyard > Any further feedback on this? Otherwise I'll merge these printf() improvements. Nikita
