Allow callable in args

[ruudk]

This makes it possible to dynamically alter the args via a callable.

[ruudk]

@spawnia Ready for review, whenever you have time 💙

[spawnia]

This makes it possible to dynamically alter the args via a callable.

I don't understand the benefit for that, please elaborate.

On the performance side, I only see this hurting. Given that Argument::listFromConfig() is called eagerly, there is no bonus for lazyness to be had here.

[ruudk]

I agree that there is no performance benefit of doing this lazily.

But it allows for using yield to return arguments that are depending on conditions.

Example:

fn() {
  yield 'id' => ['type' => Type::int()];
  if ($this->someFeatureFlag()) {
    yield 'other' => ['type' => Type::int()];
  }
  if ($this->someSpecialFlag()) {
    yield 'special' => ['type' => Type::int()];
  }
}

Obviously, we can also generate this array before constructing the type, or we can use a method that returns the flat array.
But everywhere we allow for callable that can yield results, except here.

[spawnia]

But everywhere we allow for callable that can yield results, except here.

Disagree, we only do that when it brings performance benefits. Other config options don't allow it, e.g. name.

I think it is somewhat misleading to offer this option since in other cases lazyness helps performance. In this case, it hurts performance - whether it is used or not. Thank you for the suggestion, but I am going to pass on this.