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Date: Tue, 18 May 2021 20:56:50 +0100
Message-ID: <CA+p1FabuPBuruEmAk-auRfYHZ+uDgiK4wMerocbRjVTqKrn_wQ@mail.gmail.com>
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Partial function application
From: davidgebler@gmail.com (David Gebler)

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On Tue, May 18, 2021 at 2:45 PM Larry Garfield <larry@garfieldtech.com>
wrote:

> User-space functions have always accepted more arguments than they're
> defined with.  They just get dropped off the end silently, unless you use
> func_get_args() or variadics.  While I know not everyone likes that
> "feature", it means that extra trailing ? "arguments" don't feel weird to
> me.  They just get dropped off the end and we move on with life.  At least
> that's how I conceptualize them.
>

This is my question about the partials feature, though; does the
implementation have potential to reasonably be confusing? if it's
essentially a convenient way of creating a closure, why would extra
arguments passed in the closure call be passed to the wrapped function,
rather than discarded?

function foo(int $a, int $b, int ...$p) { ... }
$partial = foo(?, 10);

$partial(5, 15, 25);

Intuitively, because the existing convention is extra unused parameters in
user defined functions are silently ignored, I think I would expect the
above to be equivalent to something like:

$partial = fn(int $a) => foo($a, 10);
$partial(5, 15, 25); // 15 and 25 are lopped off to no effect

and not

$partial = fn(int $a, int ...$params) => foo($a, 10, ....$params);

But correct me if I'm wrong, isn't the latter what the RFC effectively
proposes?


>
> --Larry Garfield
>
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