Feature request: Allow array merging / replacement in native parser

[bmack]

If you work with additionalAttributes in Tag-based ViewHelpers, it would be highly beneficial to have a good "array_replace_recursive" logic.

Example:

<f:media additionalAttributes="{additionalAttributes}" />

But if you want to add more values from another array, a logic such as

<f:media additionalAttributes="{additionalAttributes} + {key: 'my-value'}" />

would be really cool.

[s2b]

I think this could be solved by adding the spread operator for arrays (maybe also for ViewHelper tags at a later point):

<my:viewhelper additionalAttributes="{ title: 'my title', ...attrs }" />

[s2b]

I made an attempt to implement this in #810

[lolli42]

related #336

[NamelessCoder]

First option with two variables would be made possible by #396.