Document how to change base type of an enum

[Blacksmoke16]

• Add TypeNode.base_type for Enum types
• Add Enum.base_type that uses the macro method
• Mention the ability to change the base type in the Enum API docs

[Blacksmoke16]

Umm, not sure why specs failed. They passed locally for me. Some caching issue?

[asterite]

std specs also run with the current compiler, and base_type is not defined there. You can implement it by doing typeof(values.first)

[Blacksmoke16]

@asterite But how are all the other macro methods useable? {% if @type.has_attribute?("Flags") %} is a TypeNode method and that doesn't cause things to break.

EDIT: NVM, I misread. I suppose, but think this macro method would be most ideal :/. Maybe I'll add a todo to update it after the next release.

[straight-shoota]

Can you show a use case for this? typeof(value) already works to determine the base type. So this is essentially just adding a dedicated method for this? Where is this needed?

[Blacksmoke16]

@straight-shoota It originally came from some chat in Gitter. https://gitter.im/crystal-lang/crystal?at=5f7afbbc6e0eb8446967c41e

I'd maybe ask @HertzDevil what he was doing it for. But IMO, there should be a better API for getting that type than doing a typeof of one of the values given it's known at compile time anyway.

[straight-shoota]

Unless there's a common use case I'd say type(value) is totally fine. No need for adding an extra part to the API. typeof is evaluated at compile time, so there's no runtime impact.

[Blacksmoke16]

Will leave it up to @HertzDevil then. If he doesn't have any specific use cases then I'm fine with closing, or at least revert the new method and keep the doc updates.

[Blacksmoke16]

I kinda forgot about this, but I just reverted the methods and just made this document how to change the base type of an enum.