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[RFC Proposal] Null Coalesce Equal Operator

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Midori Kocak

10 years ago

Hi all,

Remember my question about ??= operator?

Forgive my rookieness and let me introduce my first RFC here: https://wiki.php.net/rfc/null_coalesce_equal_operator <https://wiki.php.net/rfc/null_coalesce_equal_operator>

Let me also include here the introduction I wrote:

Combined assignment operators are around since 1970's, appearing first in the C language. Consider the following code $x = $x + 3 that has the ability to be shortened into $x += 3. Hence PHP is a web focused language, ?? operator is used to check something's existence like $username = $_GET['user'] ?? 'nobody'; However due to common variable names are much longer than $username the use of ?? self assignment, creates repeated code. $this->request->data['comments']['user_id'] = $this->request->data['comments']['user_id'] ?? ‘value’; It is also intuitive to use combined assignment operator null coalesce checking for self assignment.

I am sure there would be some language mistakes, please also forgive me for them too.

Currently I created a working implementation here: https://github.com/php/php-src/pull/1795 <https://github.com/php/php-src/pull/1795> you can see a terminal working with my implementation also here: http://imgur.com/zLlVFup <http://imgur.com/zLlVFup>

I hope I managed to write a simple and understandable RFC. Thank you all for your efforts.

Best Wishes,

Midori Kocak
Computer Scientist & Engineer / ZCPE
http://www.mynameismidori.com <http://www.mynameismidori.com/>

Sara Golemon

10 years ago

On Wed, Mar 9, 2016 at 10:14 AM, Midori Kocak <mtkocak@gmail.com> wrote:

> Remember my question about ??= operator?
> https://wiki.php.net/rfc/null_coalesce_equal_operator
>

As I said before, I support this.  The whole thing feels like a
no-brainer in terms of implementing it.

Davey mentioned on twitter[1] the idea of shortening it to `X ?= Y`,
but I think that would be inconsistent with other operators (e.g. *=
versus **=)  and would complicate further evolutions of syntax such as
adding the `X ?:= Y` assignment operator (as shorthand for `X = X ?:
Y`).

-Sara

1 - https://twitter.com/dshafik/status/707504022224154626

Ryan Pallas

10 years ago

On Wed, Mar 9, 2016 at 11:14 AM, Midori Kocak <mtkocak@gmail.com> wrote:

> Hi all,
>
> Remember my question about ??= operator?
>
> Forgive my rookieness and let me introduce my first RFC here:
> https://wiki.php.net/rfc/null_coalesce_equal_operator <
> https://wiki.php.net/rfc/null_coalesce_equal_operator>
>

This looks great! I hope it makes it into the language for sure.

One comment though, voting section should not be opened until after the
required discussion period.

Jakub Kubíček

10 years ago

Hi Midori,

what about targetting this to the next PHP 7.x?

--
Kubis
On 10-Mar-2016 12:11 am, "Ryan Pallas" <derokorian@gmail.com> wrote:

Midori Kocak

10 years ago

Hi,

I fixed that, corrected some typos and closed voting.

Thank you for feedbacks,
Midori

Sara Golemon

10 years ago

On Wed, Mar 9, 2016 at 10:14 AM, Midori Kocak <mtkocak@gmail.com> wrote:

> Let me introduce my first RFC here: https://wiki.php.net/rfc/null_coalesce_equal_operator >
>

I've jumped on the bandwagon by adding a second RFC related to this
one: https://wiki.php.net/rfc/short_ternary_equal_operator which
focused on the short-ternary operator with the same goal of creating
and assignment version of the operation.

We can probably discuss them as a single concept since they relate to
the same underlying principle (consistency in binary operations in the
language), but I made it a separate RFC in case we want different
voting or have different concerns regarding them.

If that's a terrible idea, I can close the new one and let Midori add
?: to her original RFC.

-Sara

Pierrick Charron

10 years ago

Hi Sara,

Just to let you know that I took the liberty to correct the title of your
RFC. It was still null coalesce equal operator :)

Otherwise I'm +1 for both RFC

Pierrick

On 10 March 2016 at 22:01, Sara Golemon <pollita@php.net> wrote:

Sara Golemon

10 years ago

On Thu, Mar 10, 2016 at 8:47 PM, Pierrick Charron <pierrick@adoy.net> wrote:

> Just to let you know that I took the liberty to correct the title of your
> RFC. It was still null coalesce equal operator :)
>

Ooops.  Thanks :)

Andrew Faulds

10 years ago

Hi Midori,

Midori Kocak wrote:

> Forgive my rookieness and let me introduce my first RFC here: https://wiki.php.net/rfc/null_coalesce_equal_operator <https://wiki.php.net/rfc/null_coalesce_equal_operator>

I think this is a reasonable proposal. I had foreseen that we might add
a ??= operator some day when I wrote the original RFC for the ?? operator.

I do have one thing to add, though. It's something of a nitpick, but the
name ought to be the "null-coalescing assignment operator". This would
follow the convention of referring to +=, -= etc. as compound/combined
assignment operators[1][2], not "equal" operators (which sounds more
like what == and === do, to me) and avoids the mistake ("coalesce"
instead of "coalescing") that I originally made in my RFC for ??.[3] I
think that RFC naming is important, because the name the author chooses
for a feature tends to be the one that ends up in the manual.

Anyway, thank you for your RFC!

[1] http://php.net/manual/en/language.operators.assignment.php
[2]
https://github.com/php/php-langspec/blob/master/spec/10-expressions.md#compound-assignment
[3] https://blog.ajf.me/2015-12-07-poorly-named-rfcs

--
Andrea Faulds
https://ajf.me/