On Tue, Feb 11, 2025, at 17:06, Valentin Udaltsov wrote:
> On Friday, 7 Feb 2025 at 10:45, Faizan Akram Dar <he...@faizanakram.me> wrote:
>>
>>
>> On Fri, 7 Feb 2025, 08:30 Mihail Liahimov, <91lia...@gmail.com> wrote:
>>> Thank you for your answer. Now I will give examples for better
>>> understanding.
>>>
>>> Simple examples from Typescript:
>>>
>>> let foo = ...
>>> foo!.bar()
>>> foo!.someProperty.baz()
>>>
>>> Examples of potentially using in PHP:
>>> Without this operator we writing this code:
>>>
>>> $foo = ...
>>>
>>> if ($foo === null) {
>>> throw new FooIsNullException();
>>> }
>>>
>>> $foo->bar.
>>>
>>> With this operator:
>>>
>>> $foo!->bar
>>> $foo!->someProperty->method();
>>> $foo!->someProperty->anotherProperty!->method();
>>>
>>> I think the postfix operator would be illogical in PHP because my operator
>>> is similar to the existing nullsafe operator in syntax. And it would be
>>> strange if its syntax were different.
>>> Or we can implement both operator syntaxes: prefix for accessing
>>> properties, and postfix for use with variables, as in your example.
>>>
>>> Nullsafe:
>>> $foo?->bar;
>>> Not null assertion:
>>> $foo!->bar;
>>>
>>> If variable bar would be null - php will throw an exception. But now i dont
>>> know which exception it would be :)
>>>
>>> This operator will be useful in cases where a null value in a specific
>>> place will violate the domain logic. Usually we write either assertions or
>>> checks and throw our exceptions for this. But it seems to me that the not
>>> null assertion operator will help avoid writing unnecessary code. The
>>> problem, of course, will be catching errors. It is not clear how to catch
>>> errors by a specific value. I will think about it.
>>
>>
>> Hi,
>>
>> I don't see the point of this operator, php doesn't allow any operation over
>> null.
>>
>> See https://3v4l.org/UJ5eg
>>
>> It's throwing warning (mostly for backwards compatibility), I'd rather have
>> it throw error in next php version.
>>
>> Static analysis already complain about it, so whats the point of !->
>> operator?
>> https://phpstan.org/r/c9d6e7b3-ac66-4e91-81e8-af0cafdc976c
>>
>>
>>>
>
> > Static analysis already complain about it
>
> That's exactly where `!` is helpful. If at a certain point I am sure that a
> property must not be null and I want to make that explicit (to both developer
> and static analyzer), I can use
> `assert($obj->prop !== null)`. However, that requires an extra line of code.
> `$obj->prop!->x` would be much prettier.
>
> --
> Valentin
I don't necessarily agree that it is prettier. It also is kinda pointless to
use in parameter type hints because by default, it cannot be nullable unless
you explicitly declare it is nullable.
Personally, what I would rather see would be making variables non-null by
default. In other words, no variable can store null unless explicitly declared
as such. Something like this:
$canBeNull? = null; // ?= means the variable on the left can hold null
$cannotBeNull = null; // TypeError
This gets us closer to typed languages, but still very free-form. You can
assign anything you want into either variable, but you can only assign null to
$canBeNull.
We already have this, sorta, via parameter types, and it would be nice to
extend it to the rest of the language as well.
— Rob
