Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:109800
MIME-Version: 1.0
References: <CAF+90c9Q2Hyr33ZfJ9QV9KYDovuAmD2ZV4UHfx=jL5_5itvnQQ@mail.gmail.com>
In-Reply-To: <CAF+90c9Q2Hyr33ZfJ9QV9KYDovuAmD2ZV4UHfx=jL5_5itvnQQ@mail.gmail.com>
Date: Thu, 23 Apr 2020 08:29:57 +0200
Message-ID: <CAFPFaM+ky053ku9Gm4yeD5iVcQF_uOtBPtRvg9nys+XyjhR=Fg@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="00000000000050195b05a3ef61c4"
Subject: Re: [PHP-DEV] printf() improvements
From: george.banyard@gmail.com ("G. P. B.")

--00000000000050195b05a3ef61c4
Content-Type: text/plain; charset="UTF-8"

On Wed, 22 Apr 2020 at 15:25, Nikita Popov <nikita.ppv@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

--00000000000050195b05a3ef61c4--