Req #44298 [Fbk->NoF]: Allow switch() to track multiple variables.
| From: | php-bugs at lists dot php dot net | Date: | Sun, 18 Jan 2015 04:22:18 +0000 |
| Subject: | Req #44298 [Fbk->NoF]: Allow switch() to track multiple variables. | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-190016@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=44298&edit=1
ID: 44298
Updated by: php-bugs@lists.php.net
Reported by: php at dafydd dot com
Summary: Allow switch() to track multiple variables.
-Status: Feedback
+Status: No Feedback
Type: Feature/Change Request
Package: *General Issues
Operating System: Mac/Doesn't matter
PHP Version: 5.2.5
Private report: N
New Comment:
No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
If this is not the case and you are able to provide the
information that was requested earlier, please do so and
change the status of the bug back to "Re-Opened". Thank you.
Previous Comments:
------------------------------------------------------------------------
[2015-01-07 20:51:22] danack@php.net
Hi, this is actually possible already in PHP already, and doesn't need any extra functionality.
You can specify a function to be called to combine multiple arguments into a single value inside
case statements like this:
function f($value, $access = null) {
$knownAccessTypes = [
'read-only',
'read-write'
];
if (in_array($access, $knownAccessTypes)) {
return $value.$access;
}
return $value;
}
function multiSwitchFunction($value, $access = null) {
switch (f($value, $access)) {
case f('a', 'read-only'): return 'a r';
case f('a', 'read-write'): return 'a w';
case f('a'): return 'a default';
case f('b', 'read-only'): return 'b r';
case f('b', 'read-write'): return 'b w ';
case f('c', 'read-only'): return 'c r';
case f('c', 'read-write'): return 'c w';
case f('d', 'read-only'): return 'd r';
case f('d', 'read-write'): return 'd w' ;
default: return "unknown";
}
}
var_dump(multiSwitchFunction('a', 'read-write'));
var_dump(multiSwitchFunction('a', 'foobar'));
var_dump(multiSwitchFunction('d', 'read-write'));
var_dump(multiSwitchFunction('d', 'foobar'));
If that doesn't suite your needs, it might be better to discuss the exact feature you would
like on the PHP internals list, where an RFC could be discussed.
------------------------------------------------------------------------
[2008-02-29 23:41:29] php at dafydd dot com
Description:
------------
In writing with PHP, I have frequently come across situations where I would have to nest switch()
functions. So, I thought of an alternative.
Reproduce code:
---------------
Current code:
Suppose I have one variable limited to four specific values, and a second variable that identifies
whether or not the first variable can be changed. Right now, I have to do this:
switch ($value) {
case 'a':
switch ($access) {
case 'read-only':
case 'read-write':
}
case 'b':
switch ($access) {
case 'read-only':
case 'read-write':
}
case 'c':
switch ($access) {
case 'read-only':
case 'read-write':
}
case 'd':
switch ($access) {
case 'read-only':
case 'read-write':
}
}
Expected result:
----------------
Instead of doing that, how about changing switch to track multiple variables. Perhaps like this:
switch ($value, $access) {
case ('a', 'read-only'):
case ('a', 'read-write'):
case ('a', default):
case ('b', 'read-only'):
case ('b', 'read-write'):
case ('b', default):
case ('c', 'read-only'):
case ('c', 'read-write'):
case ('c', default):
case ('d', 'read-only'):
case ('d', 'read-write'):
case ('d', default):
case (default, default):
}
This would reduce repetition in coding!
Actual result:
--------------
I fully anticipate that this would be an "incorporate into PHP 7" class of new feature.
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=44298&edit=1