Add docs for Enum#value

[lbguilherme]

I noticed this method wasn't really documented, although it is used in a doc example.

[beta-ziliani]

Thanks!

[asterite]

I think this could be put in struct Enum in primitives.cr. It's an actual method, not a pseudo-method.

[beta-ziliani]

@asterite help me here, if it isn't listed in enum.cr nor primitive.cr, and it's not a pseudo method, what is it? 👻

[lbguilherme]

I think this could be put in struct Enum in primitives.cr. It's an actual method, not a pseudo-method.

I couldn't find a def value anywhere for Enum. primitives.cr doesn't define it. So I assumed it was a pseudo-method.

[asterite]

This PR is probably fine, though!

[lbguilherme]

Found it! Not very documentation-friendly though.

crystal/src/compiler/crystal/types.cr

Lines 2736 to 2741 in 58e8fc5

	def initialize(program, namespace, name, @base_type)
	super(program, namespace, name)
	add_def Def.new("value", [] of Arg, Primitive.new("enum_value", @base_type))
	metaclass.as(ModuleType).add_def Def.new("new", [Arg.new("value", restriction: Path.global(@base_type.to_s))], Primitive.new("enum_new", self))
	end

[beta-ziliani]

Nice! But then, since it's a primitive, it might make sense to move it to primitive.cr like Ary said.

[asterite]

Actually it's impossible to do because value's type depends on the enum type. Enum should somehow be generic, but currently it's not.

[asterite]

With that in mind, maybe doing nothing for now is better

[beta-ziliani]

We need

struct Enum(T) where T < Int

Ref #934, which even has a proposed implemented according to #934 (comment)

[straight-shoota]

Yes, it's a regular method and can be overriden by implementing types. It's definitely not pseudo.

The docs are fine. I think we could just move them to enum.cr and simply define #value delegating to previous_def.