Den 2018-06-14 kl. 11:21, skrev Rowan Collins:
On 14 June 2018 at 09:35, Nikita Popov <nikita....@gmail.com> wrote:
On Thu, Jun 14, 2018 at 6:53 AM, Sara Golemon <poll...@php.net> wrote:
Just for casual discussion at this point:
https://github.com/php/php-src/pull/3297
switch ($a) {
case FOO:
// Works exactly as current behavior.
break;
case == FOO:
// Nearly identical, though not using the ZEND_CASE optimization.
// Can probably make this equivalent to `case FOO`, but it felt
like an interesting direction.
break;
case === FOO:
// Only triggers if `$a === FOO`, no type juggling
break;
}
Love it? Hate it? See obvious flaws? The implementation is just a
rushed proof of concept, not something I've labored over, it may well
have bugs. Certainly wouldn't target anything earlier than 7.4, if at
all.
I like the general idea here (switch with strict type comparison), but not
super fond of the particular syntax and implementation.
I think if people want to use strict matching, they'll quite likely want to
have it on all cases. Something like "strict switch ($expr) {}" or "switch
strict ($expr) {}" or "switch (strict $expr) {}" or "switch ($expr) strict
{}" or "switch ($expr) { strict; }" or whatever would be preferable in that
case.
For ages, I've had an idea along these lines kicking around. Like Nikita,
I was assuming that all branches would want strict comparison or none, so
was thinking of putting the operator at the top, something like "switch
($expr) use (===)". I figured it could then be extended so the "===" could
be substituted for any binary operator; for instance, you could match
values into ranges with "switch ($score) use (>=)".
That said, I can see an attraction in a form with the operator on the
branch, if operators other than "==" and "===" are supported; for the range
example, it might be handy to have cases for ">= 50", "> 0", and "=== 0".
I prefer reusing "===" in some way over the word "strict", even if no other
operators are supported, because "strict" could mean a number of things -
"strictly no fall-throughs", for instance - and I think that could cause
confusion (people already expect "strict types" to mean more than it does).
Regards,
Yup, I also like this idea very much. Using the === syntax is a clear
message on what's it all about. Having the ability to extend it to
other operators is also interesting, e.g. !== & !=.
Another point is that by keeping switch keyword it would be relatively
easy to upgrade legacy code, making it more robust.
Of course there is a use for a new keyword like match extending the
functionality even more. Maybe we can have both?
I'm thinking if one should be able to have like:
switch ($a) {
case === FOO:
break;
case !== BAR:
break;
}
or:
switch ($a) with !== {
case FOO:
break;
case BAR:
break;
default:
break;
}
or:
switch ($a, ===) {
case FOO:
break;
case BAR:
break;
}
r//Björn Larsson
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