Alias for multiple mixins / traits

Question
1

Hello everyone! What is the best way to give an alias for multiple mixed-in traits and group them? For example, I’d want to write something like this:

type NounAttributes = HasDeclensionTypeAndSubtype with HasStressType with HasStem with IsPartOfSpeech with HasSyntacticAndMorphologicalCharacteristics with HasInitialForm with HasGender with HasAnimacy

type NounFormAttributes = HasNumber with HasCase with HasStress

class NounForm private[Noun]() extends NounAttributes with NounFormAttributes { ... }

instead of:

class NounForm private[Noun]() extends
    //noun attributes
    HasDeclensionTypeAndSubtype with HasStressType with HasStem with IsPartOfSpeech
    with HasSyntacticAndMorphologicalCharacteristics with HasInitialForm with HasGender with HasAnimacy
    //noun form attributes
    with HasNumber with HasCase with HasStress { ... }

One solution that came to my head is to define an empty trait in the Noun class like this:

private[Noun] trait NounFormAttributes extends HasNumber with HasCase with HasStress

and use it instead, but I don’t like it and can’t understand why the ‘type’ keyword doesn’t work in this case.

Thank you in advance!

2

What is wrong with the trait? That is exactly what you want.

The type keyword doesn’t work, because you can not extend a type, but a class or a trait.

3

Because in this case it doesn’t add any behavior aspects and serves only for grouping. It doesn’t even work as a marker interface. I hoped that there is a way to make the ‘type’ keyword work because all I need is to give an alternative high-level descriptive name for a group of traits for more readability. But maybe this is too much of perfectionism. :slightly_smiling_face:

4

Yes it does, it is the behavior of all the other behaviors mixed together.