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;;; -*- mode: scheme; coding: utf-8; -*-
;; Copyright (C) 2010, 2013 Free Software Foundation, Inc.
;; Copyright (C) 2003 André van Tonder. All Rights Reserved.
;;
;; Permission is hereby granted, free of charge, to any person
;; obtaining a copy of this software and associated documentation
;; files (the "Software"), to deal in the Software without
;; restriction, including without limitation the rights to use, copy,
;; modify, merge, publish, distribute, sublicense, and/or sell copies
;; of the Software, and to permit persons to whom the Software is
;; furnished to do so, subject to the following conditions:
;;
;; The above copyright notice and this permission notice shall be
;; included in all copies or substantial portions of the Software.
;;
;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
;; BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
;; ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
;; CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
;; SOFTWARE.
;; Modified by Andreas Rottmann for Guile.
(define-module (test-srfi-45)
#:use-module (test-suite lib)
#:use-module (srfi srfi-45))
(define-syntax test-output
(syntax-rules ()
((_ expected proc)
(let ((output (call-with-output-string proc)))
(pass-if (equal? expected output))))))
(define-syntax test-equal
(syntax-rules ()
((_ expected expr)
(pass-if (equal? expected expr)))))
(define test-leaks? #f)
(define-syntax test-leak
(syntax-rules ()
((_ expr)
(cond (test-leaks?
(display "Leak test, please watch memory consumption;")
(display " press C-c when satisfied.\n")
(call/cc
(lambda (k)
(sigaction SIGINT (lambda (signal) (k #t)))
expr)))))))
;=========================================================================
; TESTS AND BENCHMARKS:
;=========================================================================
;=========================================================================
; Memoization test 1:
(test-output "hello"
(lambda (port)
(define s (delay (begin (display 'hello port) 1)))
(test-equal 1 (force s))
(test-equal 1 (force s))))
;=========================================================================
; Memoization test 2:
(test-output "bonjour"
(lambda (port)
(let ((s (delay (begin (display 'bonjour port) 2))))
(test-equal 4 (+ (force s) (force s))))))
;=========================================================================
; Memoization test 3: (pointed out by Alejandro Forero Cuervo)
(test-output "hi"
(lambda (port)
(define r (delay (begin (display 'hi port) 1)))
(define s (lazy r))
(define t (lazy s))
(test-equal 1 (force t))
(test-equal 1 (force r))))
;=========================================================================
; Memoization test 4: Stream memoization
(define (stream-drop s index)
(lazy
(if (zero? index)
s
(stream-drop (cdr (force s)) (- index 1)))))
(define (ones port)
(delay (begin
(display 'ho port)
(cons 1 (ones port)))))
(test-output "hohohohoho"
(lambda (port)
(define s (ones port))
(test-equal 1
(car (force (stream-drop s 4))))
(test-equal 1
(car (force (stream-drop s 4))))))
;=========================================================================
; Reentrancy test 1: from R5RS
(letrec ((count 0)
(p (delay (begin (set! count (+ count 1))
(if (> count x)
count
(force p)))))
(x 5))
(test-equal 6 (force p))
(set! x 10)
(test-equal 6 (force p)))
;=========================================================================
; Reentrancy test 2: from SRFI 40
(letrec ((f (let ((first? #t))
(delay
(if first?
(begin
(set! first? #f)
(force f))
'second)))))
(test-equal 'second (force f)))
;=========================================================================
; Reentrancy test 3: due to John Shutt
(let* ((q (let ((count 5))
(define (get-count) count)
(define p (delay (if (<= count 0)
count
(begin (set! count (- count 1))
(force p)
(set! count (+ count 2))
count))))
(list get-count p)))
(get-count (car q))
(p (cadr q)))
(test-equal 5 (get-count))
(test-equal 0 (force p))
(test-equal 10 (get-count)))
;=========================================================================
; Test leaks: All the leak tests should run in bounded space.
;=========================================================================
; Leak test 1: Infinite loop in bounded space.
(define (loop) (lazy (loop)))
(test-leak (force (loop))) ;==> bounded space
;=========================================================================
; Leak test 2: Pending memos should not accumulate
; in shared structures.
(let ()
(define s (loop))
(test-leak (force s))) ;==> bounded space
;=========================================================================
; Leak test 3: Safely traversing infinite stream.
(define (from n)
(delay (cons n (from (+ n 1)))))
(define (traverse s)
(lazy (traverse (cdr (force s)))))
(test-leak (force (traverse (from 0)))) ;==> bounded space
;=========================================================================
; Leak test 4: Safely traversing infinite stream
; while pointer to head of result exists.
(let ()
(define s (traverse (from 0)))
(test-leak (force s))) ;==> bounded space
;=========================================================================
; Convenient list deconstructor used below.
(define-syntax match
(syntax-rules ()
((match exp
(() exp1)
((h . t) exp2))
(let ((lst exp))
(cond ((null? lst) exp1)
((pair? lst) (let ((h (car lst))
(t (cdr lst)))
exp2))
(else 'match-error))))))
;========================================================================
; Leak test 5: Naive stream-filter should run in bounded space.
; Simplest case.
(define (stream-filter p? s)
(lazy (match (force s)
(() (delay '()))
((h . t) (if (p? h)
(delay (cons h (stream-filter p? t)))
(stream-filter p? t))))))
(test-leak
(force (stream-filter (lambda (n) (= n 10000000000))
(from 0)))) ;==> bounded space
;========================================================================
; Leak test 6: Another long traversal should run in bounded space.
; The stream-ref procedure below does not strictly need to be lazy.
; It is defined lazy for the purpose of testing safe compostion of
; lazy procedures in the times3 benchmark below (previous
; candidate solutions had failed this).
(define (stream-ref s index)
(lazy
(match (force s)
(() 'error)
((h . t) (if (zero? index)
(delay h)
(stream-ref t (- index 1)))))))
; Check that evenness is correctly implemented - should terminate:
(test-equal 0
(force (stream-ref (stream-filter zero? (from 0))
0)))
;; Commented out since it takes too long
#;
(let ()
(define s (stream-ref (from 0) 100000000))
(test-equal 100000000 (force s))) ;==> bounded space
;======================================================================
; Leak test 7: Infamous example from SRFI 40.
(define (times3 n)
(stream-ref (stream-filter
(lambda (x) (zero? (modulo x n)))
(from 0))
3))
(test-equal 21 (force (times3 7)))
;; Commented out since it takes too long
#;
(test-equal 300000000 (force (times3 100000000))) ;==> bounded space
;======================================================================
; Test promise? predicate (non-standard Guile extension)
(pass-if "promise? predicate"
(promise? (delay 1)))
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