Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:62504
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 74.125.82.170 as permitted sender)
Message-ID: <50396B77.6070202@gmail.com>
Date: Sun, 26 Aug 2012 02:19:03 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0
MIME-Version: 1.0
To: Ferenc Kovacs <tyra3l@gmail.com>
CC: David Muir <davidkmuir@gmail.com>, 
 PHP internals list <internals@lists.php.net>
References: <502EBAA4.9090007@gmail.com> <CAH-PCH54ROtaWa6nr6OwDxH7rxtJaaHOa813-NFDMRoN7DFwcg@mail.gmail.com> <50381196.4090606@gmail.com> <CAH-PCH7QctpYoY9fu5AshvPsdhPaYJsmVg6G5EyjBGf8W5srsg@mail.gmail.com> <5039102F.5010305@gmail.com> <CAH-PCH5=85Q3uZst-AkWkWeip_b1j7qamO8ysbxgRpHtpqx76g@mail.gmail.com> <C8E959A2-0B61-4D00-9F69-BA48D274DB05@gmail.com> <CAH-PCH6=Zy_q=k7tWc=JxW=ePOX6=pxKkBuyAvL6B9oN8tjwbg@mail.gmail.com>
In-Reply-To: <CAH-PCH6=Zy_q=k7tWc=JxW=ePOX6=pxKkBuyAvL6B9oN8tjwbg@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Subject: Re: [PHP-DEV] Combined assignment operator for short ternary
From: krebs.seb@gmail.com (Sebastian Krebs)

Am 26.08.2012 01:57, schrieb Ferenc Kovacs:
>
>      > So you are saying that your (teams) IDE doesn't tell you the method
>      > signature which contains also the default values?
>      > I guess that the fact that many of the php core functions have
>     optional
>      > arguments and non null defaults must be really a PITA for you.
>
>     I think what he was alluding to is the problem where one changes the
>     default.
>
>     All usages of the method/function then need to be updated. Using
>     null today is very much like using the proposed 'default' parameter
>     skipping RFC.
>
>
> true, using null as a default value for your optional arguments means
> that you don't really need the parameter skipping RFC (at least for the
> functions that you control) or the named params, because you can pass
> null for the in-between optional arguments.
> ofc. most modern IDEs also have some kind of refactoring feature, which
> would make it easier for you to update the function calls to reflect the
> change in the default value, but it would be harder to tell the original
> intention ($limit is 30 here, because it was the default and the caller
> wanted to set the next optional argument, or $limit is intentionally set
> to 30 and the next optional argument also happen to be needed).
> thanks for clearing that one up for me.
>
> Having every optional argument defaulting to null means that it can be
> frequent scenario, when you have a variable, which is guaranteed to be
> defined, but can be null.
> But I still think that it isn't that frequent that you want to keep the
> non falsely values or set a default value otherwise.
> I mean if you expect a number, then you don't want your passed 0 to be
> replaced with the default, or if you expect a string, you don't want "0"
> or maybe even "" to be replaced with the default, etc..
> So you couldn't use the ternary assignment for those scenarios.

Yes, it doesn't work in this cases, but I must say

- I try to avoid optional parameters whereever useful. The caller should 
be aware of what he is doing. I prefer to define "preferred values" as 
constants instead, that can be used whereever a preferred behaviour is 
wanted.
- I do't implement very much functions/methods, where (e.g.) 0 is 
allowed and should _not_ be the default (same for strings and so on), 
thus '$index = $index ?: 0;' is valid regardless wether $index is 0 or 
null in the first place. Or if I expect a string the empty string '' is 
most of the time a special cases (or required). If I expect an object is 
just obvious, that they can never evaluate to false.

I don't think we need argue about this, because this two points are more 
or less personal preferences/opinions. But this said there are only some 
few edge cases (for me), where I need to distinguish between '', 0, 
null, ..., and in this few cases, I can still use the good old `$index = 
is_null($index) ? 123 : $index;` ;).

At the end: It works just great to use null as general-purpose-default. 
I don't care about a special 'default'-keyword, because in my mind 
something like that already exists in form of 'null': It's either "the 
default primitive value", or "no-object" (in case an object was 
expected, but not required).


>
> --
> Ferenc Kovács
> @Tyr43l - http://tyrael.hu