Ask HN: PHP, interfaces, typehinting subtype and LSP?
6 comments
It has to work with all subtypes of stdClass, since in order for the interface to hold its word, I need to be able to get an object thats implements I, and pass it any stdClass, regardless of what they do with it.
Based on the research I've made it is legal by the OO principles and SHOULD work but it got omitted somehow in the trade-off during the implementation.
Also NOT available in java.lang.
Also NOT available in java.lang.
Say I have a function that accepts I as argument:
function my_func(I $x)
{
$x->foo(new stdClass);
}
This is a question that would be better suited to asking on stackoverflow.com
{
function foo(stdClass $arg);
}
class Test extends stdClass
{
}
class Implementation implements I
{
function foo(Test $arg)
{
}
}
Result:
Fatal error: Declaration of InterfaceImplementation::foo() must be compatible with I::foo(stdClass $arg) in test.php on line XY
How come that I can't type hint a subtype in the implementation?