On Mon, May 3, 2021 at 6:44 PM Delta Echo <[email protected]> wrote:
> Hi, Is there any document that explains how recursive type definitions like
>
> type stateFn func(*Scanner) stateFn
>
> are handled in Go?
Not sure what "handle" means in this case. The language specs do not
mention recursive types, so what follows is my opinion only.
A recursive type is a type size of which cannot be computed because
for that you need to know its size in the first place.
So `type t struct { t }` is recursive: https://play.golang.org/p/M64qW_XnnsG
But `type t struct { *t }` is not:
https://play.golang.org/p/7EE2hzcRst1 because the fixed size of a
pointer "breaks" the recursive chain.
In this ad hoc definition `type stateFn func(*Scanner) stateFn` is not
recursive and thus compiles just fine:
https://play.golang.org/p/sLDd4K58FDG
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