On Sat, 23 Apr 2016 14:18:56 +0300, Dan Ackroyd <[email protected]>
wrote:
On 22 April 2016 at 05:12, Marcio Almada <[email protected]> wrote:
Hello everyone,
We just completed the draft for the "Callable Types" RFC.
There seems to be one thing missing from the RFC; please could you add
an example where the parameter and return types are also 'typed'
callables?
Presumably it would look something like this?
function reduce(int $a, int $b, callable(int, callable(int, int):int
$math):int $reducer): callable(int, int):int {
return $reducer($a, $b);
}
Are there any limits to how far down the callable type can be defined ?
cheers
Dan
Hey Dan,
thanks for reviewing.
I have just added a paragraph about nested callables, I'll copy paste it
here:
Nested callables can be used with no imposed limit on the nesting level.
function foo(callable(callable(int)) $cb) {
$cb(function (int $i) {
var_dump($i);
});
}
foo(function (callable(int) $intPrinter) {
$intPrinter(123);
});
There's currently no way to reference callable signature from within
itself, meaning there's no way to make recursive signatures like below:
function bar(callable(int $number): callable(int $number):
callable(int $number): parent_callable $recursiveCb) { // this wouldn't
work currently
}
To add to that, nested callables can get pretty unreadable quickly, both
of these problems would be best solved by a typedef feature of some kind,
added to PHP later.
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