Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:66725
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.212.182 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <CANa7=gy2eqNPQu4ERNC_PEGYfZSQ=SavnXbc70fZV+=eq0894A@mail.gmail.com>
References: <CANa7=gxotTUa=56qGw5qCqx7k9J2COztqk9XhsPeYZXrKyFLiw@mail.gmail.com>
 <CACwt+Jfp3bxoC0raeHFSMNJS09fZa=oBWXbuVO5nUg0_c17KfA@mail.gmail.com> <CANa7=gy2eqNPQu4ERNC_PEGYfZSQ=SavnXbc70fZV+=eq0894A@mail.gmail.com>
Date: Wed, 20 Mar 2013 15:43:36 -0300
Message-ID: <CANa7=gyxu+2vE=4zZH83K3MaTZm_EtuyRCkjJ+xYNDRHShWO4Q@mail.gmail.com>
To: internals@lists.php.net
Content-Type: text/plain; charset=ISO-8859-1
Subject: Re: [PHP-DEV] Method check - Can someone create a RFC for it?
From: carlos.vini@gmail.com (Carlos Rodrigues)

Like Mike emaild me, i can just change my code to something like
$obj->getImage()->getUrl(), where getImage() will return a mock object
with getUrl() returning an empty string.

But my request here is not about this case only.
Imagine you have a web page with 3 blocks of information. Let's say
"news", "partners" and "blog".

Now if for some reason you didn't code it right, you might get a fatal
error in one of these "blocks".

I'd love to have a way to try/catch these blocks, Currently i can only
do this using ajax, or running shell exec "php block.php" for each
one.

If we could catch fatal errors, or at least the "Call to a member
function on a non-object", we could have this code in our Zend
Framework implementations, wrapping each view in a try/catch, and
showing a "error, sorry", in case the view has errors.

- Carlos

On Wed, Mar 20, 2013 at 3:33 PM, Carlos Rodrigues <carlos.vini@gmail.com> wrote:
> Thx for your reply Patrick,
>
> I agree that it's partially syntactic sugar, as you said. But when you do this:
>
> $obj = new stdClass();
> echo $obj->foo;
>
> PHP will not if foo is not declared. It will output an empty string.
> But if you have a method
>
> echo @$obj->foo();
> echo 'end';
>
> It will give you a fatal error.
>
> Even using @ to suppress error messages it won't echo the 'end' part.
>
> Since short array syntax (like [1,2]) was not extremely necessary and
> was accepted, maybe someones has a better idea than i had to address
> this.
>
> Carlos
>
> On Wed, Mar 20, 2013 at 3:22 PM, Patrick ALLAERT <patrickallaert@php.net> wrote:
>> 2013/3/20 Carlos Rodrigues <carlos.vini@gmail.com>:
>>> Hi,
>>>
>>> I'd like to suggest a new functionality for PHP. I don't know the
>>> internals, and i can't create a patch implementing this. I'm writing
>>> here in case someone likes this idea and write a RFC.
>>>
>>> We've had a problem recently where one of our developers forgot an "if".
>>>
>>> So instead of writing
>>> if ($obj->image) {
>>> echo $obj->image->getUrl();
>>> }
>>>
>>> He wrote:
>>> echo $obj->image->getUrl();
>>>
>>> Here, locally, it was working cause we had the image. But when we
>>> updated the online version we got a "Fatal error: Call to a member
>>> function getUrl() on a non-object" cause someone didn't upload the
>>> image in one of the records that we're on the home page.
>>>
>>> Fatal errors like this can't be catched by a try/catch. And since this
>>> getUrl() was not essential for the page, we'd better output an empty
>>> string then having the site offline.
>>>
>>> One might say: "you guys should have tested it better", or "The image
>>> field should be mandatory in the back end."
>>> And it's true, he should have written that extra "if {}".
>>>
>>> Examining this problem we happened to stumble open Ruby's and
>>> Coffescript's method check.
>>> Something like this:
>>>
>>> $obj->image?->getUrl()?;
>>>
>>> So my suggestion is:
>>>
>>> Create something like $foo->bar?() or $foo->bar()?, where you don't
>>> care whether the function exists, or if $foo is an object. If it
>>> doesn't exist you just return null.
>>> I guess there are plenty of systems out there where it's better to
>>> output an empty string than having your site offline, just cause the
>>> programmer couldn't test it completely.
>>
>> That's syntactic sugar we can live without as it does not really
>> encourage good programming practices.
>> If you don't care about those, then you can already just do:
>>
>> echo @$obj->image->getUrl();
>>
>> Patrick