fae24ab496
* Types now start with a Capital letter, because. * Boolean expression no longer start with the letter b.
20 lines
520 B
Racket
20 lines
520 B
Racket
#lang s-exp "../cur.rkt"
|
|
(require "sugar.rkt")
|
|
(provide Maybe none some)
|
|
|
|
(data Maybe : (forall (A : Type) Type)
|
|
(none : (forall (A : Type) (Maybe A)))
|
|
(some : (forall* (A : Type) (a : A) (Maybe A))))
|
|
|
|
(module+ test
|
|
(require rackunit "bool.rkt")
|
|
#;(check-equal?
|
|
(case* Maybe (some Bool true)
|
|
(lambda (x : (Maybe Bool)) Bool)
|
|
[(none (A : Type)) IH: ()
|
|
false]
|
|
[(some (A : Type) (x : A)) IH: ()
|
|
;; TODO: Don't know how to use dependency yet
|
|
(if x true false)])
|
|
true))
|