match-struct.rkt

#lang racket/base

#|
cpu time: 111 real time: 113 gc time: 0
cpu time: 141 real time: 142 gc time: 0
cpu time: 1125 real time: 1131 gc time: 4
|#

(module plain racket/base
  (provide (struct-out st))
  (struct st [x]))

(module contracted racket/base
  (require racket/contract
           (submod ".." plain))

  (provide
    (contract-out (struct st ([x integer?])))))

(require racket/match
         'plain
         (prefix-in c: 'contracted))

(define a (st 42))
(define b (c:st 42))

(collect-garbage)
(collect-garbage)
(collect-garbage)

(time
  (for ([x 10000000])
    (match a
      [(? st?) 'ok])))

(collect-garbage)
(collect-garbage)
(collect-garbage)

(time
  (for ([x 10000000])
    (match a
      [(st _) 'ok])))

(collect-garbage)
(collect-garbage)
(collect-garbage)

(time
  (for ([x 10000000])
    (match b
      [(c:st _) 'ok])))