Get enum underlying type in compile time

Help & Support
1

Is it possible to get enum underlying type in compile type (i.e. in macro)? Stuck with this trying to support enum types in storage schema providing correct storage type like UInt8/UInt16 so to reduce storage usage but also support large enums if needed

2

TypeNode doesn’t support it but you could try one of the following:

enum Foo : Int8
  X
end

# `NumberLiteral#kind : SymbolLiteral`
{{ Foo.constant(Foo.constants.first).kind }} # => :i8

# `EnumDef#base_type : Path`
macro foo(x)
  {{ x.base_type }} # => Int8
end

foo enum Foo : Int8
  X
end
1 Like
3

Related: Document how to change base type of an enum by Blacksmoke16 · Pull Request #9803 · crystal-lang/crystal · GitHub. Was a PR to add this, but wasn’t a valid use case to warrant the addition at the time.