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To: "Christoph M. Becker" <cmbecker69@gmx.de>, internals@lists.php.net
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Message-ID: <dbfae3d5-e317-f680-9fe6-240ab142d105@gmail.com>
Date: Fri, 28 Dec 2018 16:02:26 -0800
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Subject: Re: [PHP-DEV] Inconsistent float to string vs. string to float
 casting
From: smalyshev@gmail.com (Stanislav Malyshev)

Hi!

> Regarding the decimal separator (aka. decimal point), the behavior of
> casting float to string is inconsistent with casting string to float.
> While the former regards the current locale, the latter always expects a
> decimal point regardless of the locale.  This breaks round-trips for
> locales which use something else than a dot as decimal separator (e.g.
> German, which uses a comma), for instance:

That may be inconvenient, but changing it now would be way worse IMHO.
Ideally, system conversions would return well-defined result (locale as
a global is a *horrible* idea which can only be explained by it's
genesis in simpler times where most of the software was written to be
run in one specific environment and user putting a pack of punch cards
into the reader would only need them to be processed in one locale) and
for configurable outcome you'd use functions that receive explicit
parameters.

> As for me, the question is not *if*, but rather *when* and *how* this
> inconsistency should be resolved.  Regarding the *when*, it seems to me

If you mean that loading "0.3" from string would suddenly stop working
in Germany, then never. If you mean that (string)0.3 would return "0.3"
and not "0,3" in Germany, then again I'd say probably never, though very
slightly less confidently. Those people who didn't want it already have
code to deal with it, and those that wanted it would have their unit
tests crash and burn and their data pipelines blow up.

I think it's a very bad idea to change such things, which would create
hundreds of year-persons of headache to anybody daring to upgrade. I
understand it's a bad situation, but I think the right exit of it is to
tell people that want predictable roundtrip results to use specific
number conversion functions, and not exchange one mess to another,
BC-breaking and havoc-wreaking, mess. I agree that the right thing to do
would be to have (string)0.3 to always use dot and never use locale (did
I mention I think global locale is a horrible idea?) but that ship has
sailed. I don't see a use case that would be well served by breaking the
BC now.

-- 
Stas Malyshev
smalyshev@gmail.com