Den 2019-04-14 kl. 18:52, skrev Nikita Popov:
On Mon, Apr 8, 2019 at 4:06 PM Nikita Popov <nikita....@gmail.com> wrote:
On Wed, Mar 13, 2019 at 4:56 PM Nikita Popov <nikita....@gmail.com> wrote:
Hi internals,
Motivated by the recent list comprehensions RFC, I think it's time we
took another look at short closures:
https://wiki.php.net/rfc/arrow_functions_v2
This is based on a previous (withdrawn) proposal by Levi & Bob. It uses
the syntax
fn($x) => $x * $multiplier
and implicit by-value variable binding. This example is roughly
equivalent to:
function($x) use($multiplier) { return $x * $multiplier; }
The RFC contains a detailed discussion of syntax choices and binding
modes.
Regards,
Nikita
Heads up: I plan to start voting on this RFC tomorrow if nothing new comes
up.
Most of the discussion was (as expected) about the choice of syntax.
Ultimately I think there are many reasonable choices we can make here, but
we should stick to a specific proposal for the purposes of the RFC vote.
None of the given arguments convinced me that some other syntax is
*strictly* better than the proposed fn($x, $y) => $x*$y -- it's more a
matter of some choices being slightly better in one case and slightly worse
in another. My personal runner-up would be \($x, $y) => $x*$y, but I
suspect that there are some people who are more strongly biased against
"sigil salad" than I am...
Nikita
So, there's been quite a bit of extra discussion here... unfortunately I
can't say that it really clarified anything, we're still circling around
different syntax choices, with the main contenders being fn, \ and ==>.
fn($x) => $x
fn($x, $y) => $x*$y
\$x => $x
\($x, $y) => $x*$y
$x ==> $x
($x, $y) ==> $x*$y
I think the main qualities of these possibilities are:
* Implementation complexity: fn and \ are easy, ==> is hard (lexer hack).
* Availability of reduced syntax: \ an ==> have a special single-argument
syntax, fn doesn't.
* Obviousness/readability: fn and ==> are obvious, while \ is not.
Especially \$x => $x looks quite obscure to the uninitiated (is that a
variable escape, like it would be in strings?)
At this point I'm considering to either a) move forward with fn() as the
choice I'd consider most likely to gather a consensus or b) have a
secondary three-way vote between these three syntax choices.
Nikita
Hi,
Even if a consensus wasn't reached I feel that there has been
quite a constructive discussion, where the pros and cons were
drilled down for the syntax alternatives at hand.
So having no voting rights myself, but alternative B for voting
looks ok in my eyes. One could ask having three alternatives
or two? OTOH, those three alternatives are now on the table
and nothing else, so all three. But if implementation of ==>
are much to overwhelming, only two.
r//Björn L
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