type-expander

History

Fred Fu a56777e97c change polymorphic types to type constructors this fix ensured the code to be forward compatible with the upcoming TR's [kind system](https://github.com/racket/typed-racket/pull/1143)		2021-11-05 13:39:24 -04:00
..
base-lang-test-1.rkt	Squashed commits.	2017-04-27 22:54:34 +02:00
base-lang-test-2.rkt	Squashed commits.	2017-04-27 22:54:34 +02:00
base-lang-test-3.rkt	Squashed commits.	2017-04-27 22:54:34 +02:00
lang-test-1.rkt	Squashed commits.	2017-04-27 22:54:34 +02:00
lang-test-2.rkt	Squashed commits.	2017-04-27 22:54:34 +02:00
lang-test-3.rkt	Squashed commits.	2017-04-27 22:54:34 +02:00
readme.rkt	Squashed commits.	2017-04-27 22:54:34 +02:00
test-contracts-to-types.rkt	Skip test-contracts-to-types on 6.4, there seems to be a problem (and I don't really want to try to find out what it is, as it works with later versions).	2017-05-10 16:36:24 +02:00
type-expander-test.rkt	change polymorphic types to type constructors	2021-11-05 13:39:24 -04:00

readme.rkt

#lang typed/racket
(require type-expander
         typed/rackunit
         (for-syntax racket/list))

(define-type-expander (Repeat stx)
  (syntax-case stx ()
    [(_ t n)
     #`(List #,@(map (λ (x) #'t)
                     (range (syntax->datum #'n))))]))

(: five-strings (→ String (Repeat String 5)))
(define (five-strings x)
  (list x "a" "b" "c" "d"))

(check-equal? (five-strings "hello")
              '("hello" "a" "b" "c" "d"))

(check-equal? (ann (five-strings "moon") (Repeat String 5))
              '("moon"  "a" "b" "c" "d"))