Better class addition which preserve previously assigned classes

[Vlczech]

If I use some classes on inputs, usage of:
{input some-input, class => 'some-class'}
leads to overwrite previously set classes.

However:
$form['some-input']->getControlPrototype()->addAttributes(['class' => 'some-class'])
leads to merge previously set classes with the other one classes.

[uestla]

This doesn't work since it does the same thing as the native {input /} macro - see here.

->getPrototype()->addClass('form-control') however works...

[Vlczech]

That's strange... If i added some class to input and use yours {input forminput, class => 'form-control'}, class which i set was ignored. If I tried to use {$form['forminput']->getprototype()->addClass('form-control')} {$form['forminput']->getprototype()->addAttributes(['class' => 'form-control'])} immediately before your code (and delete , class => 'form-control' from this input), then the class was set in the final code. That's why I decided for this pull request.

When I have a moment, i will try once again.

[uestla]

Yes that's correct, but in this pull request you're using addAttributes(), not addClass() :)

[Vlczech]

Sorry, that was a mistake, that i wrote another function thatn in pull request.

I used addAttributes as in pull request - editted previous message ;)