> (qfib 100)
354224848179261915075
> (fib 20)
6765
> (fib 30)
832040
> (fib 32)
2178309
> (delay (fib 32))
#<promise>
> (define promise (delay (fib 32)))
> promise
#<promise>
> (+ 2 4)
6
> (* 3 5)
15
> (force promise)
2178309
> (force promise)
2178309
> (delay (car '()))
#<promise>
> (define error (car '()))
[image] [image] mcar: contract violation
  expected: mpair?
  given: ()
> (define error (delay (car '())))
> (force error)
[image] [image] mcar: contract violation
  expected: mpair?
  given: ()
> (define l '())
> (car l)
[image] [image] mcar: contract violation
  expected: mpair?
  given: ()
> (define first (car l))
[image] [image] mcar: contract violation
  expected: mpair?
  given: ()
> (define first (delay (car l)))
> (set! l (list 1 2 3))
> (force first)
1
> (define undefined (delay (car l2)))
> (define l2 '( 1 2 3))
> (force undefined)
1
> (delay (car '()))
[image] [image] mcar: contract violation
  expected: mpair?
  given: ()
> promise?
[image] [image] promise?: undefined;
 cannot reference an identifier before its definition
> (cons-stream 1 (cons-stream 2 (cons-stream 3 the-empty-stream)))
> (head s)
1
> (head (tail s))
2
> (head (head (tail s)))
[image] [image] mcar: contract violation
  expected: mpair?
  given: 2
> (head (tail (tail s)))
3
> (tail (tail (tail s)))
()
> (tail s)
(2 . #<promise>)
[image] [image] b: undefined;
 cannot reference an identifier before its definition
> s
[image] [image] s: undefined;
 cannot reference an identifier before its definition
> s
(1 . #<promise>)
[image] [image] cons-stream: undefined;
 cannot reference an identifier before its definition
> (delay 1)
#<procedure>
> (force 1)
[image] [image] application: not a procedure;
 expected a procedure that can be applied to arguments
  given: 1
> (delay (fib 32))
#<procedure>
> (define promise (delay (fib 32)))
> (force promise)
2178309
> (force promise)
2178309
> (force promise)
2178309
> (define promise (delay (fib 32)))
> s
(1 . #<procedure:.../scheme/streams.scm:13:46>)
> (head (tail s))
2
> (head (head (tail s)))
[image] [image] mcar: contract violation
  expected: mpair?
  given: 2
> (head (tail (tail s)))
[image] [image] b: undefined;
 cannot reference an identifier before its definition
> (define b 'video)
> (head (tail (tail s)))
video
> (enum 1 100)
(1 . #<procedure:.../scheme/streams.scm:13:46>)
> (head (tail (tail (enum 1 100))))
3
> (from-to 1 10)
(1 2 3 4 5 6 7 8 9 10)
> (enum 1 10)
(1 . #<procedure:.../scheme/streams.scm:14:46>)
> (length (from 1 10000000))
[image] Interactions disabled; out of memory
> (length (from-to 1 1000000))
1000000
> (enum 1 1000000)
(1 . #<procedure:.../scheme/streams.scm:14:46>)
> (enum 1 100000000000000)
(1 . #<procedure:.../scheme/streams.scm:14:46>)
> (take 10 (enum 1 100000000000000))
(1 2 3 4 5 6 7 8 9 10)
> (take 10 (enum 1 100000000000000))
> (find-stream odd? (enum 0 100000000)) 
(1 . #<procedure:.../scheme/streams.scm:14:46>)
> (take 10 (from 15))
(15 16 17 18 19 20 21 22 23 24)
> (find-stream odd? (from 0))
(1 . #<procedure:.../scheme/streams.scm:14:46>)
> (find-stream negative? (from 0))
[image] [image] user break
> (find-stream negative? (enum 10 100))
#f
> (find-stream negative? (enum 10 1000))
#f
> (take 10 nats)
(0 1 2 3 4 5 6 7 8 9)
> (take 10 fibs)
(0 1 1 2 3 5 8 13 21 34)
> (take 100 fibs)
(0
 1
 1
 2
 3
 5
 8
 13
 21
 34
 55
 89
 144
 233
 377
 610
 987
 1597
 2584
 4181
 6765
 10946
 17711
 28657
 46368
 75025
 121393
 196418
 317811
 514229
 832040
 1346269
 2178309
 3524578
 5702887
 9227465
 14930352
 24157817
 39088169
 63245986
 102334155
 165580141
 267914296
 433494437
 701408733
 1134903170
 1836311903
 2971215073
 4807526976
 7778742049
 12586269025
 20365011074
 32951280099
 53316291173
 86267571272
 139583862445
 225851433717
 365435296162
 591286729879
 956722026041
 1548008755920
 2504730781961
 4052739537881
 6557470319842
 10610209857723
 17167680177565
 27777890035288
 44945570212853
 72723460248141
 117669030460994
 190392490709135
 308061521170129
 498454011879264
 806515533049393
 1304969544928657
 2111485077978050
 3416454622906707
 5527939700884757
 8944394323791464
 14472334024676221
 23416728348467685
 37889062373143906
 61305790721611591
 99194853094755497
 160500643816367088
 259695496911122585
 420196140727489673
 679891637638612258
 1100087778366101931
 1779979416004714189
 2880067194370816120
 4660046610375530309
 7540113804746346429
 12200160415121876738
 19740274219868223167
 31940434634990099905
 51680708854858323072
 83621143489848422977
 135301852344706746049
 218922995834555169026)
> (map-stream (lambda (x) (+ x 1)
> (take 10 (map-stream (lambda (x) (* x x)) nats))
(0 1 4 9 16 25 36 49 64 81)
> (take 10 (map-stream (lambda (x) (* x x)) fibs))
(0 1 1 4 9 25 64 169 441 1156)
> (take 10 (map-stream (lambda (x) (* x x)) (enum 1 10)))
(1 4 9 16 25 36 49 64 81 100)
> (take 10 (map-stream (lambda (x) (* x x)) (enum 1 20)))
(1 4 9 16 25 36 49 64 81 100)
> (take 10 (map-stream (lambda (x) (* x x)) (enum 1 5)))
(1 4 9 16 25)
> 
> (take 10 (filter-stream odd? (map-stream (lambda (x) (* x x)) nats)))
(1 9 25 49 81 121 169 225 289 361)
> (map + '(1 2 3) '(4 5 6))
(5 7 9)
> (take 10 (zip-stream + nats nats))
(0 2 4 6 8 10 12 14 16 18)
> (take 10 (map-stream + nats nats))
(0 2 4 6 8 10 12 14 16 18)
> (take 10 (map-stream + nats nats nats nats nats))
(0 5 10 15 20 25 30 35 40 45)
> (cons-stream 1 a)
(1 . #<procedure:.../scheme/streams.scm:14:46>)
> a
[image] [image] a: undefined;
 cannot reference an identifier before its definition
> (define a 2)
> (define a nats)
> (take 10 ones)
[image] [image] ones: undefined;
 cannot reference an identifier before its definition
> (take 10 ones)
(1 1 1 1 1 1 1 1 1 1)
> (take 10 nats)
(0 1 2 3 4 5 6 7 8 9)
> (head (tail nats))
1
[image] define: not allowed in an expression context in: (define tail (r5rs:lambda (nats2) (map-stream + nats2 ones)))
> (take 10 fibs)
(0 1 1 2 3 5 8 13 21 34)
> (take 100 fibs)
[image] [image] user break
> (take 20 fibs)
(0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181)
> (take 30 fibs)
[image] Interactions disabled; out of memory
> (take 30 fibs)
(0
 1
 1
 2
 3
 5
 8
 13
 21
 34
 55
 89
 144
 233
 377
 610
 987
 1597
 2584
 4181
 6765
 10946
 17711
 28657
 46368
 75025
 121393
 196418
 317811
 514229)
> (take 10 (from 2))
(2 3 4 5 6 7 8 9 10 11)
> (sieve (from 2))
(2 . #<procedure:.../scheme/streams.scm:14:46>)
> ((not-divisible 2) 4)
> (take 10 (sieve (from 2)))
(2 3 5 7 9 11 13 15 17 19)
> (take 10 (sieve (from 2)))
(2 3 5 7 11 13 17 19 23 29)
> (take 100 (sieve (from 2)))
(2
 3
 5
 7
 11
 13
 17
 19
 23
 29
 31
 37
 41
 43
 47
 53
 59
 61
 67
 71
 73
 79
 83
 89
 97
 101
 103
 107
 109
 113
 127
 131
 137
 139
 149
 151
 157
 163
 167
 173
 179
 181
 191
 193
 197
 199
 211
 223
 227
 229
 233
 239
 241
 251
 257
 263
 269
 271
 277
 281
 283
 293
 307
 311
 313
 317
 331
 337
 347
 349
 353
 359
 367
 373
 379
 383
 389
 397
 401
 409
 419
 421
 431
 433
 439
 443
 449
 457
 461
 463
 467
 479
 487
 491
 499
 503
 509
 521
 523
 541)
>