9 lines
169 B
Racket
9 lines
169 B
Racket
#lang typed-scheme
|
|
|
|
(: x : '())
|
|
(define x '())
|
|
|
|
|
|
(define-typed-struct even-struct ([x : (U #f odd-struct)]))
|
|
(define-typed-struct odd-struct ([x : (U #f even-struct)]))
|