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Reply-To: me@afilina.com
Date: Thu, 14 Jan 2021 13:12:34 -0500
Message-ID: <CAFrKnm=FWUuPRVERUR7hNk5Skyj6VjT+Q4fs6aT74bxwzZXRAw@mail.gmail.com>
To: Andrew Brown <browner12@gmail.com>
Cc: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="000000000000b7e2d705b8e033b0"
Subject: Re: [PHP-DEV] Feature Proposal
From: afilina@gmail.com (Anna Filina)

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> So if some calling code wants to override a later parameter, it currently
needs to pass a value to the earlier optional parameters.

I think that this is a code smell that should be addressed by a better
design. Here's a detailed explanation of why one should use default
parameters sparingly, along with alternatives: https://afilina.com/null-hell

I feel like such a feature would enable developers to dig themselves
a deeper hole towards unmaintainable code. That's just my 2 cents.

Anna Filina

On Thu, Jan 14, 2021 at 12:52 PM Andrew Brown <browner12@gmail.com> wrote:

> This is my first foray into PHP internals, so please let me know if I'm
> doing something wrong. Currently just following the instructions from
> https://wiki.php.net/rfc/howto.
>
> Currently this proposal is only a "concept".
>
> I propose we add a "default" keyword that can be passed as an argument
> into a function/method call. This would allow the calling code to defer to
> the function signature for the value of a parameter.
>
> Traditionally, all optional parameters are placed towards the end of the
> function parameter list, but as we all know, sometimes this order can be
> tricky. So if some calling code wants to override a later parameter, it
> currently needs to pass a value to the earlier optional parameters.
>
> A current solution around this is to define all defaults in the body of
> the function rather than in the signature.
>
> [image: Screen-Shot-2021-01-14-at-11.45.09-AM.jpg]
>
> However, this adds some extra boilerplate, and we can't use default
> parameters as they were really intended.
>
> My proposal is to add a new `default` keyword to be passed as an argument.
>
> [image: Screen-Shot-2021-01-14-at-11.44.57-AM.jpg]
>
> The first call of the function here is how we currently have to do things.
> We have to explicitly pass `true` in as the second parameter.
>
> However, in the second call, we now use the new `default` keyword, which
> will defer to the function signature for the default value of `$param2`.
>
> Thanks all, looking forward to some feedback!
>
> --
> Andrew M. Brown
>

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