I am not sure that own mapper is really needed. I agree that mapping can be enhanced for <module> and <presenter> placeholders, but in this case there is no need to use own mapper.

I for one would use such mapper. It really enables modularity across packages and default implementation can be reused as a fallback for custom implementation.

Now I can have multiple packages sharing same <module> by convention ie. namespace:

<?php $mapping = [ 'shop' => [
 'packageA/src/Shop/Presenters',
 'packageB/src/Shop/Presenters',
// ...
] ]

For now I have to prefix each package, because using multiple directories for same <module> is not possible. From my experience using paths with multiple modules is not really scalable across packages ie. <AModule>/<AdminModule>. Sharing <module> makes things simpler.

👍
But I would remove the setMapping method in IPresenterMapper interface

I think that use <module> and <presenter> placeholders would be good, but mapper could be usefully.
Mapper has no disadvantage, has only benefits in my opinion

@matej21 you are rigth. I removed setMapping from interface

👍 for this

👍 I like it.
It would be possible to create MapperChain, chaining multiple mappers for different modules of application (and even better, it would work greatly addons which use presenters). Maybe it would be the best to add it into Nette as well (it could be done in separate PR later).

What is purpose of this PR? To add <module> and <presenter> placeholders? It will not help, because everybody will have to write own mapper. Implementations will be fragmented.

What is the advantage of "split" 2-methods IPresenterFactory into 2-methods IPresenterFactory plus 2-methods IPresenterMapper? Is there really such big need to create your own mappers?