I want to execute code everytime a apecific attribute is assiggned to a function.
For example:
<?php
#[Attribute]
class exampleAttribute
{
public function __construct()
{
echo "exampleAttribute called";
}
}
#[exampleAttribute()]
function exampleFunction()
{
//...
}
But in this example the echo statement is never called. How do I do this?
Attributes are not instantiated automatically, because there is no particular time when they "become attached" - they are just part of the definition of that function, like the types and argument names.
Instead, you have to access them via reflection, as discussed in the PHP manual. Specifically, you would use a ReflectionFunction object to read the attribute, and then the newInstance method to instantiate it. Only when you do that will your echo line run.
