Generic notation in PHPDoc vs. plain array notation

gistfile1.php

<?php
/**
 * @template <T> The type of the individual elements
 */
class ArrayCollection implements IteratorAggregate
{
    private $elements;

    /**
     * @param array<T> $elements
     */
    public function __construct(array $elements)
    {
        $this->elements = $elements;
    }
 
    /**
     * @return Iterator<T>
     */
    public function getIterator()
    {
         return new ArrayIterator($this->elements);
    }
}

// usage
/** @type ArrayCollection<Foo> $col */
$col = new ArrayCollection();

foreach ($col as $elem) { 
    // $elem is instance of Foo here
}
?>

<?php
class ArrayCollection implements IteratorAggregate
{
    private $elements;

    /**
     * @param mixed[] $elements
     */
    public function __construct(array $elements)
    {
        $this->elements = $elements;
    }
 
    /**
     * @return ArrayIterator
     */
    public function getIterator()
    {
         return new ArrayIterator($this->elements);
    }
}

// usage
/** @type ArrayCollection|Foo[] $col */
$col = new ArrayCollection();

foreach ($col as $elem) { 
    // $elem is instance of Foo here
}
?>

Could these ideas be successfully condensed into just this one syntax:

@type (class name or primitive type 'array')<(optional key type, ) (required member type) (description)

I have been thinking quite a bit about this proposal in the past time and to be honest, it is starting to grow on me. Though I am not so sure about the @template tag since that would only serve a purpose for a Collection object that only intends to be used with a specific set of values (that and I don't think the name @template is intuitive).

Some concerns that I still have:

• How to deal with generics where the value may be of several types? Use the or operator (|) as has been done so far?
• We should also support multi-dimensional notations

I think we sould keep the or operator for working with several types. But what do you mean by "multi-dimensional notations"?

Coming from a Java perspective, I would love some kind of Generics support in PHP and/or PHPDOC. 👍