Explain the concept of composalizable

[JJ]

The problem

While checking the (not-so) new behavior of does I found the concept of composalizable, which are classes that, even if they cannot be composed, behave as if they were.

Suggestions

Apparently just enums behave that way. But we'll have to research it a bit further.

[JJ]

Composalizable is mentioned in Raku/roast#402 as not specced yet.

[jnthn]

Generally, archetypes are a mechanism that describe the way a certain kind of type behaves, and so answer questions like "does it make sense to inherit from this", "does it make sense to compose this", "can this thing turn into something I can inherit" (for example, you an is SomeRule, which results in inheriting from the pun), or "can this thing turn into something I can compose" (the role case that you asked about). The point was to avoid hardcoding things like "role", "grammar", and "class" into the compiler as special cases when deciding the contexts in which a type may be used, thus allowing for a more extensible meta-space.

Apparently just enums behave that way.

This matches my recollection. Here's the implementation of what it means to composalize an enum.

[jnthn]

Ah, and to add: the archetypes were considered as something to eventually spec provided the design held up, so no objections to documenting.

[JJ]

El dom., 22 dic. 2019 a las 20:07, Jonathan Worthington (< notifications@github.com>) escribió:

Ah, and to add: the archetypes were considered as something to eventually spec provided the design held up, so no objections to documenting.

Thanks!