about summary refs log tree commit diff stats
path: root/sandbox/005-sandbox.mu
blob: ee58638b62336a63620b72e8863f2b7af0e03339 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
## running code from the editor and creating sandboxes
#
# Running code in the sandbox editor prepends its contents to a list of
# (non-editable) sandboxes below the editor, showing the result and maybe a
# few other things (later layers).
#
# This layer draws the menubar buttons in non-editable sandboxes but they
# don't do anything yet. Later layers implement each button.

def! main [
  local-scope
  open-console
  clear-screen 0/screen  # non-scrolling app
  env:&:environment <- new-programming-environment 0/filesystem, 0/screen
  env <- restore-sandboxes env, 0/filesystem
  render-all 0/screen, env, render
  event-loop 0/screen, 0/console, env, 0/filesystem
]

container environment [
  sandbox:&:sandbox  # list of sandboxes, from top to bottom. TODO: switch to &:list:sandbox
  render-from:num
  number-of-sandboxes:num
]

after <programming-environment-initialization> [
  *result <- put *result, render-from:offset, -1
]

container sandbox [
  data:text
  response:text
  # coordinates to track clicks
  # constraint: will be 0 for sandboxes at positions before env.render-from
  starting-row-on-screen:num
  code-ending-row-on-screen:num  # past end of code
  screen:&:screen  # prints in the sandbox go here
  next-sandbox:&:sandbox
]

scenario run-and-show-results [
  local-scope
  trace-until 100/app  # trace too long
  assume-screen 50/width, 15/height
  # recipes.mu is empty
  assume-resources [
  ]
  # sandbox editor contains an instruction without storing outputs
  env:&:environment <- new-programming-environment resources, screen, [divide-with-remainder 11, 3]
  render-all screen, env, render
  # run the code in the editors
  assume-console [
    press F4
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # check that screen prints the results
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .divide-with-remainder 11, 3                       .
    .3                                                 .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  screen-should-contain-in-color 7/white, [
    .                                                  .
    .                                                  .
    .                                                  .
    .                                                  .
    .divide-with-remainder 11, 3                       .
    .                                                  .
    .                                                  .
    .                                                  .
    .                                                  .
  ]
  screen-should-contain-in-color 245/grey, [
    .                                                  .
    .                                                  .
    .──────────────────────────────────────────────────.
    .                                                  .
    .                                                  .
    .3                                                 .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # run another command
  assume-console [
    left-click 1, 80
    type [add 2, 2]
    press F4
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # check that screen prints both sandboxes
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .divide-with-remainder 11, 3                       .
    .3                                                 .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
]

after <global-keypress> [
  # F4? load all code and run all sandboxes.
  {
    do-run?:bool <- equal k, 65532/F4
    break-unless do-run?
    screen <- update-status screen, [running...       ], 245/grey
    error?:bool <- run-sandboxes env, resources, screen
    # F4 might update warnings and results on both sides
    screen <- render-all screen, env, render
    {
      break-if error?
      screen <- update-status screen, [                 ], 245/grey
    }
    screen <- update-cursor screen, current-sandbox, env
    loop +next-event
  }
]

def run-sandboxes env:&:environment, resources:&:resources, screen:&:screen -> errors-found?:bool, env:&:environment, resources:&:resources, screen:&:screen [
  local-scope
  load-ingredients
  errors-found?:bool <- update-recipes env, resources, screen
  # check contents of editor
  <begin-run-sandboxes>
  current-sandbox:&:editor <- get *env, current-sandbox:offset
  {
    sandbox-contents:text <- editor-contents current-sandbox
    break-unless sandbox-contents
    # if contents exist, first save them
    # run them and turn them into a new sandbox
    new-sandbox:&:sandbox <- new sandbox:type
    *new-sandbox <- put *new-sandbox, data:offset, sandbox-contents
    # push to head of sandbox list
    dest:&:sandbox <- get *env, sandbox:offset
    *new-sandbox <- put *new-sandbox, next-sandbox:offset, dest
    *env <- put *env, sandbox:offset, new-sandbox
    # update sandbox count
    sandbox-count:num <- get *env, number-of-sandboxes:offset
    sandbox-count <- add sandbox-count, 1
    *env <- put *env, number-of-sandboxes:offset, sandbox-count
    # save all sandboxes
    # needs to be before running them, in case we die when running
    save-sandboxes env, resources
    # clear sandbox editor
    init:&:duplex-list:char <- push 167/§, 0/tail
    *current-sandbox <- put *current-sandbox, data:offset, init
    *current-sandbox <- put *current-sandbox, top-of-screen:offset, init
  }
  # run all sandboxes
  curr:&:sandbox <- get *env, sandbox:offset
  idx:num <- copy 0
  {
    break-unless curr
    curr <- update-sandbox curr, env, idx
    curr <- get *curr, next-sandbox:offset
    idx <- add idx, 1
    loop
  }
  <end-run-sandboxes>
  {
    break-if resources  # ignore this in tests
    $system [./snapshot_lesson]
  }
]

# load code from disk
# replaced in a later layer (whereupon errors-found? will actually be set)
def update-recipes env:&:environment, resources:&:resources, screen:&:screen -> errors-found?:bool, env:&:environment, screen:&:screen [
  local-scope
  load-ingredients
  in:text <- slurp resources, [lesson/recipes.mu]
  reload in
  errors-found? <- copy 0/false
]

# replaced in a later layer
def update-sandbox sandbox:&:sandbox, env:&:environment, idx:num -> sandbox:&:sandbox, env:&:environment [
  local-scope
  load-ingredients
  data:text <- get *sandbox, data:offset
  response:text, _, fake-screen:&:screen <- run-sandboxed data
  *sandbox <- put *sandbox, response:offset, response
  *sandbox <- put *sandbox, screen:offset, fake-screen
]

def update-status screen:&:screen, msg:text, color:num -> screen:&:screen [
  local-scope
  load-ingredients
  screen <- move-cursor screen, 0, 2
  screen <- print screen, msg, color, 238/grey/background
]

def save-sandboxes env:&:environment, resources:&:resources -> resources:&:resources [
  local-scope
  load-ingredients
  trace 11, [app], [save sandboxes]
  current-sandbox:&:editor <- get *env, current-sandbox:offset
  # first clear previous versions, in case we deleted some sandbox
  $system [rm lesson/[0-9]* >/dev/null 2>/dev/null]  # some shells can't handle '>&'
  curr:&:sandbox <- get *env, sandbox:offset
  idx:num <- copy 0
  {
    break-unless curr
    resources <- save-sandbox resources, curr, idx
    idx <- add idx, 1
    curr <- get *curr, next-sandbox:offset
    loop
  }
]

def save-sandbox resources:&:resources, sandbox:&:sandbox, sandbox-index:num -> resources:&:resources [
  local-scope
  load-ingredients
  data:text <- get *sandbox, data:offset
  filename:text <- append [lesson/], sandbox-index
  resources <- dump resources, filename, data
  <end-save-sandbox>
]

def! render-sandbox-side screen:&:screen, env:&:environment, render-editor:render-recipe -> screen:&:screen, env:&:environment [
  local-scope
  load-ingredients
  trace 11, [app], [render sandbox side]
  old-top-idx:num <- save-top-idx screen
  current-sandbox:&:editor <- get *env, current-sandbox:offset
  row:num, column:num <- copy 1, 0
  left:num <- get *current-sandbox, left:offset
  right:num <- get *current-sandbox, right:offset
  # render sandbox editor
  render-from:num <- get *env, render-from:offset
  {
    render-current-sandbox?:bool <- equal render-from, -1
    break-unless render-current-sandbox?
    row, column, screen, current-sandbox <- call render-editor, screen, current-sandbox
    clear-screen-from screen, row, column, left, right
    row <- add row, 1
  }
  # render sandboxes
  draw-horizontal screen, row, left, right
  sandbox:&:sandbox <- get *env, sandbox:offset
  row, screen <- render-sandboxes screen, sandbox, left, right, row, render-from, 0, env
  clear-rest-of-screen screen, row, left, right
  #
  assert-no-scroll screen, old-top-idx
]

def render-sandboxes screen:&:screen, sandbox:&:sandbox, left:num, right:num, row:num, render-from:num, idx:num -> row:num, screen:&:screen, sandbox:&:sandbox [
  local-scope
  load-ingredients
  env:&:environment, _/optional <- next-ingredient
  return-unless sandbox
  screen-height:num <- screen-height screen
  hidden?:bool <- lesser-than idx, render-from
  {
    break-if hidden?
    # render sandbox menu
    row <- add row, 1
    at-bottom?:bool <- greater-or-equal row, screen-height
    return-if at-bottom?
    screen <- move-cursor screen, row, left
    screen <- render-sandbox-menu screen, idx, left, right
    # save menu row so we can detect clicks to it later
    *sandbox <- put *sandbox, starting-row-on-screen:offset, row
    # render sandbox contents
    row <- add row, 1
    screen <- move-cursor screen, row, left
    sandbox-data:text <- get *sandbox, data:offset
    row, screen <- render-code screen, sandbox-data, left, right, row
    *sandbox <- put *sandbox, code-ending-row-on-screen:offset, row
    # render sandbox warnings, screen or response, in that order
    sandbox-response:text <- get *sandbox, response:offset
    <render-sandbox-results>
    {
      sandbox-screen:&:screen <- get *sandbox, screen:offset
      empty-screen?:bool <- fake-screen-is-empty? sandbox-screen
      break-if empty-screen?
      row, screen <- render-screen screen, sandbox-screen, left, right, row
    }
    {
      break-unless empty-screen?
      <render-sandbox-response>
      row, screen <- render-text screen, sandbox-response, left, right, 245/grey, row
    }
    +render-sandbox-end
    at-bottom?:bool <- greater-or-equal row, screen-height
    return-if at-bottom?
    # draw solid line after sandbox
    draw-horizontal screen, row, left, right
  }
  # if hidden, reset row attributes
  {
    break-unless hidden?
    *sandbox <- put *sandbox, starting-row-on-screen:offset, 0
    *sandbox <- put *sandbox, code-ending-row-on-screen:offset, 0
    <end-render-sandbox-reset-hidden>
  }
  # draw next sandbox
  next-sandbox:&:sandbox <- get *sandbox, next-sandbox:offset
  next-idx:num <- add idx, 1
  row, screen <- render-sandboxes screen, next-sandbox, left, right, row, render-from, next-idx, env
]

def render-sandbox-menu screen:&:screen, sandbox-index:num, left:num, right:num -> screen:&:screen [
  local-scope
  load-ingredients
  move-cursor-to-column screen, left
  edit-button-left:num, edit-button-right:num, copy-button-left:num, copy-button-right:num, delete-button-left:num <- sandbox-menu-columns left, right
  print screen, sandbox-index, 232/dark-grey, 245/grey
  start-buttons:num <- subtract edit-button-left, 1
  clear-line-until screen, start-buttons, 245/grey
  print screen, [edit], 232/black, 25/background-blue
  clear-line-until screen, edit-button-right, 25/background-blue
  print screen, [copy], 232/black, 58/background-green
  clear-line-until screen, copy-button-right, 58/background-green
  print screen, [delete], 232/black, 52/background-red
  clear-line-until screen, right, 52/background-red
]

scenario skip-rendering-sandbox-menu-past-bottom-row [
  trace-until 100/app  # trace too long
  assume-screen 50/width, 6/height
  # recipes.mu is empty
  assume-resources [
    [lesson/0] <- [|add 2, 2|]
    [lesson/1] <- [|add 1, 1|]
  ]
  # create two sandboxes such that the top one just barely fills the screen
  env:&:environment <- new-programming-environment resources, screen, []
  env <- restore-sandboxes env, resources
  run [
    render-all screen, env, render
  ]
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 2, 2                                          .
    .──────────────────────────────────────────────────.
  ]
]

# divide up the menu bar for a sandbox into 3 segments, for edit/copy/delete buttons
# delete-button-right == right
# all left/right pairs are inclusive
def sandbox-menu-columns left:num, right:num -> edit-button-left:num, edit-button-right:num, copy-button-left:num, copy-button-right:num, delete-button-left:num [
  local-scope
  load-ingredients
  start-buttons:num <- add left, 4/space-for-sandbox-index
  buttons-space:num <- subtract right, start-buttons
  button-width:num <- divide-with-remainder buttons-space, 3  # integer division
  buttons-wide-enough?:bool <- greater-or-equal button-width, 8
  assert buttons-wide-enough?, [sandbox must be at least 30 or so characters wide]
  edit-button-left:num <- copy start-buttons
  copy-button-left:num <- add start-buttons, button-width
  edit-button-right:num <- subtract copy-button-left, 1
  delete-button-left:num <- subtract right, button-width
  copy-button-right:num <- subtract delete-button-left, 1
]

# print a text 's' to 'editor' in 'color' starting at 'row'
# clear rest of last line, move cursor to next line
def render-text screen:&:screen, s:text, left:num, right:num, color:num, row:num -> row:num, screen:&:screen [
  local-scope
  load-ingredients
  return-unless s
  column:num <- copy left
  screen <- move-cursor screen, row, column
  screen-height:num <- screen-height screen
  i:num <- copy 0
  len:num <- length *s
  {
    +next-character
    done?:bool <- greater-or-equal i, len
    break-if done?
    done? <- greater-or-equal row, screen-height
    break-if done?
    c:char <- index *s, i
    {
      # newline? move to left rather than 0
      newline?:bool <- equal c, 10/newline
      break-unless newline?
      # clear rest of line in this window
      {
        done?:bool <- greater-than column, right
        break-if done?
        space:char <- copy 32/space
        print screen, space
        column <- add column, 1
        loop
      }
      row <- add row, 1
      column <- copy left
      screen <- move-cursor screen, row, column
      i <- add i, 1
      loop +next-character
    }
    {
      # at right? wrap.
      at-right?:bool <- equal column, right
      break-unless at-right?
      # print wrap icon
      wrap-icon:char <- copy 8617/loop-back-to-left
      print screen, wrap-icon, 245/grey
      column <- copy left
      row <- add row, 1
      screen <- move-cursor screen, row, column
      # don't increment i
      loop +next-character
    }
    i <- add i, 1
    print screen, c, color
    column <- add column, 1
    loop
  }
  was-at-left?:bool <- equal column, left
  clear-line-until screen, right
  {
    break-if was-at-left?
    row <- add row, 1
  }
  move-cursor screen, row, left
]

scenario render-text-wraps-barely-long-lines [
  local-scope
  assume-screen 5/width, 5/height
  run [
    render-text screen, [abcde], 0/left, 4/right, 7/white, 1/row
  ]
  screen-should-contain [
    .     .
    .abcd.
    .e    .
    .     .
  ]
]

# assumes programming environment has no sandboxes; restores them from previous session
def restore-sandboxes env:&:environment, resources:&:resources -> env:&:environment [
  local-scope
  load-ingredients
  # read all scenarios, pushing them to end of a list of scenarios
  idx:num <- copy 0
  curr:&:sandbox <- copy 0
  prev:&:sandbox <- copy 0
  {
    filename:text <- append [lesson/], idx
    contents:text <- slurp resources, filename
    break-unless contents  # stop at first error; assuming file didn't exist
                           # todo: handle empty sandbox
    # create new sandbox for file
    curr <- new sandbox:type
    *curr <- put *curr, data:offset, contents
    <end-restore-sandbox>
    {
      break-if idx
      *env <- put *env, sandbox:offset, curr
    }
    {
      break-unless idx
      *prev <- put *prev, next-sandbox:offset, curr
    }
    idx <- add idx, 1
    prev <- copy curr
    loop
  }
  # update sandbox count
  *env <- put *env, number-of-sandboxes:offset, idx
]

# print the fake sandbox screen to 'screen' with appropriate delimiters
# leave cursor at start of next line
def render-screen screen:&:screen, sandbox-screen:&:screen, left:num, right:num, row:num -> row:num, screen:&:screen [
  local-scope
  load-ingredients
  return-unless sandbox-screen
  # print 'screen:'
  row <- render-text screen, [screen:], left, right, 245/grey, row
  screen <- move-cursor screen, row, left
  # start printing sandbox-screen
  column:num <- copy left
  s-width:num <- screen-width sandbox-screen
  s-height:num <- screen-height sandbox-screen
  buf:&:@:screen-cell <- get *sandbox-screen, data:offset
  stop-printing:num <- add left, s-width, 3
  max-column:num <- min stop-printing, right
  i:num <- copy 0
  len:num <- length *buf
  screen-height:num <- screen-height screen
  {
    done?:bool <- greater-or-equal i, len
    break-if done?
    done? <- greater-or-equal row, screen-height
    break-if done?
    column <- copy left
    screen <- move-cursor screen, row, column
    # initial leader for each row: two spaces and a '.'
    space:char <- copy 32/space
    print screen, space, 245/grey
    print screen, space, 245/grey
    full-stop:char <- copy 46/period
    print screen, full-stop, 245/grey
    column <- add left, 3
    {
      # print row
      row-done?:bool <- greater-or-equal column, max-column
      break-if row-done?
      curr:screen-cell <- index *buf, i
      c:char <- get curr, contents:offset
      color:num <- get curr, color:offset
      {
        # damp whites down to grey
        white?:bool <- equal color, 7/white
        break-unless white?
        color <- copy 245/grey
      }
      print screen, c, color
      column <- add column, 1
      i <- add i, 1
      loop
    }
    # print final '.'
    print screen, full-stop, 245/grey
    column <- add column, 1
    {
      # clear rest of current line
      line-done?:bool <- greater-than column, right
      break-if line-done?
      print screen, space
      column <- add column, 1
      loop
    }
    row <- add row, 1
    loop
  }
]

scenario run-updates-results [
  local-scope
  trace-until 100/app  # trace too long
  assume-screen 50/width, 12/height
  # define a recipe (no indent for the 'add' line below so column numbers are more obvious)
  assume-resources [
    [lesson/recipes.mu] <- [
      ||
      |recipe foo [|
      |  local-scope|
      |  z:num <- add 2, 2|
      |  reply z|
      |]|
    ]
  ]
  # sandbox editor contains an instruction without storing outputs
  env:&:environment <- new-programming-environment resources, screen, [foo]  # contents of sandbox editor
  render-all screen, env, render
  $clear-trace
  # run the code in the editors
  assume-console [
    press F4
  ]
  event-loop screen, console, env, resources
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .foo                                               .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # the new sandbox should be saved to disk
  trace-should-contain [
    app: save sandboxes
  ]
  # make a change (incrementing one of the args to 'add'), then rerun
  assume-resources [
    [lesson/recipes.mu] <- [
      ||
      |recipe foo [|
      |  local-scope|
      |  z:num <- add 2, 3|
      |  reply z|
      |]|
    ]
  ]
  $clear-trace
  assume-console [
    press F4
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # check that screen updates the result on the right
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .foo                                               .
    .5                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # no need to save sandboxes all over again
  trace-should-not-contain [
    app: save sandboxes
  ]
]

scenario run-instruction-manages-screen-per-sandbox [
  local-scope
  trace-until 100/app  # trace too long
  assume-screen 50/width, 20/height
  # empty recipes
  assume-resources [
  ]
  # sandbox editor contains an instruction
  env:&:environment <- new-programming-environment resources, screen, [print screen, 4]  # contents of sandbox editor
  render-all screen, env, render
  # run the code in the editor
  assume-console [
    press F4
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # check that it prints a little toy screen
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .print screen, 4                                   .
    .screen:                                           .
    .  .4                             .                .
    .  .                              .                .
    .  .                              .                .
    .  .                              .                .
    .  .                              .                .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
]

def editor-contents editor:&:editor -> result:text [
  local-scope
  load-ingredients
  buf:&:buffer:char <- new-buffer 80
  curr:&:duplex-list:char <- get *editor, data:offset
  # skip § sentinel
  assert curr, [editor without data is illegal; must have at least a sentinel]
  curr <- next curr
  return-unless curr, 0
  {
    break-unless curr
    c:char <- get *curr, value:offset
    buf <- append buf, c
    curr <- next curr
    loop
  }
  result <- buffer-to-array buf
]

scenario editor-provides-edited-contents [
  local-scope
  assume-screen 10/width, 5/height
  e:&:editor <- new-editor [abc], 0/left, 10/right
  assume-console [
    left-click 1, 2
    type [def]
  ]
  run [
    editor-event-loop screen, console, e
    s:text <- editor-contents e
    1:@:char/raw <- copy *s
  ]
  memory-should-contain [
    1:array:character <- [abdefc]
  ]
]

# scrolling through sandboxes

scenario scrolling-down-past-bottom-of-sandbox-editor [
  local-scope
  trace-until 100/app  # trace too long
  assume-screen 50/width, 20/height
  # initialize
  assume-resources [
  ]
  env:&:environment <- new-programming-environment resources, screen, [add 2, 2]
  render-all screen, env, render
  assume-console [
    # create a sandbox
    press F4
  ]
  event-loop screen, console, env, resources
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-down'
  assume-console [
    press page-down
  ]
  run [
    event-loop screen, console, env, resources
    cursor:char <- copy 9251/    print screen, cursor
  ]
  # sandbox editor hidden; first sandbox displayed
  # cursor moves to first sandbox
  screen-should-contain [
    .                               run (F4)           .
    .──────────────────────────────────────────────────.
    .   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-up'
  assume-console [
    press page-up
  ]
  run [
    event-loop screen, console, env, resources
    cursor:char <- copy 9251/    print screen, cursor
  ]
  # sandbox editor displays again
  screen-should-contain [
    .                               run (F4)           .
    .                                                 .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
]

# page-down updates render-from to scroll sandboxes
after <global-keypress> [
  {
    page-down?:bool <- equal k, 65518/page-down
    break-unless page-down?
    sandbox:&:sandbox <- get *env, sandbox:offset
    break-unless sandbox
    # slide down if possible
    {
      render-from:num <- get *env, render-from:offset
      number-of-sandboxes:num <- get *env, number-of-sandboxes:offset
      max:num <- subtract number-of-sandboxes, 1
      at-end?:bool <- greater-or-equal render-from, max
      break-if at-end?
      render-from <- add render-from, 1
      *env <- put *env, render-from:offset, render-from
    }
    screen <- render-sandbox-side screen, env, render
    screen <- update-cursor screen, current-sandbox, env
    loop +next-event
  }
]

# update-cursor takes render-from into account
after <update-cursor-special-cases> [
  {
    render-from:num <- get *env, render-from:offset
    scrolling?:bool <- greater-or-equal render-from, 0
    break-unless scrolling?
    cursor-column:num <- get *current-sandbox, left:offset
    screen <- move-cursor screen, 2/row, cursor-column  # highlighted sandbox will always start at row 2
    return
  }
]

# 'page-up' is like 'page-down': updates first-sandbox-to-render when necessary
after <global-keypress> [
  {
    page-up?:bool <- equal k, 65519/page-up
    break-unless page-up?
    render-from:num <- get *env, render-from:offset
    at-beginning?:bool <- equal render-from, -1
    break-if at-beginning?
    render-from <- subtract render-from, 1
    *env <- put *env, render-from:offset, render-from
    screen <- render-sandbox-side screen, env, render
    screen <- update-cursor screen, current-sandbox, env
    loop +next-event
  }
]

# sandbox belonging to 'env' whose next-sandbox is 'in'
# return 0 if there's no such sandbox, either because 'in' doesn't exist in 'env', or because it's the first sandbox
def previous-sandbox env:&:environment, in:&:sandbox -> out:&:sandbox [
  local-scope
  load-ingredients
  curr:&:sandbox <- get *env, sandbox:offset
  return-unless curr, 0/nil
  next:&:sandbox <- get *curr, next-sandbox:offset
  {
    return-unless next, 0/nil
    found?:bool <- equal next, in
    break-if found?
    curr <- copy next
    next <- get *curr, next-sandbox:offset
    loop
  }
  return curr
]

scenario scrolling-through-multiple-sandboxes [
  local-scope
  trace-until 100/app  # trace too long
  assume-screen 50/width, 20/height
  # initialize environment
  assume-resources [
  ]
  env:&:environment <- new-programming-environment resources, screen, []
  render-all screen, env, render
  # create 2 sandboxes
  assume-console [
    press ctrl-n
    type [add 2, 2]
    press F4
    type [add 1, 1]
    press F4
  ]
  event-loop screen, console, env, resources
  cursor:char <- copy 9251/  print screen, cursor
  screen-should-contain [
    .                               run (F4)           .
    .                                                 .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-down'
  assume-console [
    press page-down
  ]
  run [
    event-loop screen, console, env, resources
    cursor:char <- copy 9251/    print screen, cursor
  ]
  # sandbox editor hidden; first sandbox displayed
  # cursor moves to first sandbox
  screen-should-contain [
    .                               run (F4)           .
    .──────────────────────────────────────────────────.
    .   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-down' again
  assume-console [
    press page-down
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # just second sandbox displayed
  screen-should-contain [
    .                               run (F4)           .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-down' again
  assume-console [
    press page-down
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # no change
  screen-should-contain [
    .                               run (F4)           .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-up'
  assume-console [
    press page-up
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # back to displaying both sandboxes without editor
  screen-should-contain [
    .                               run (F4)           .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-up' again
  assume-console [
    press page-up
  ]
  run [
    event-loop screen, console, env, resources
    cursor:char <- copy 9251/    print screen, cursor
  ]
  # back to displaying both sandboxes as well as editor
  screen-should-contain [
    .                               run (F4)           .
    .                                                 .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-up' again
  assume-console [
    press page-up
  ]
  run [
    event-loop screen, console, env, resources
    cursor:char <- copy 9251/    print screen, cursor
  ]
  # no change
  screen-should-contain [
    .                               run (F4)           .
    .                                                 .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .1   edit           copy           delete          .
    .add 2, 2                                          .
    .4                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
]

scenario scrolling-manages-sandbox-index-correctly [
  local-scope
  trace-until 100/app  # trace too long
  assume-screen 50/width, 20/height
  # initialize environment
  assume-resources [
  ]
  env:&:environment <- new-programming-environment resources, screen, []
  render-all screen, env, render
  # create a sandbox
  assume-console [
    press ctrl-n
    type [add 1, 1]
    press F4
  ]
  event-loop screen, console, env, resources
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-down' and 'page-up' a couple of times. sandbox index should be stable
  assume-console [
    press page-down
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # sandbox editor hidden; first sandbox displayed
  # cursor moves to first sandbox
  screen-should-contain [
    .                               run (F4)           .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-up' again
  assume-console [
    press page-up
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # back to displaying both sandboxes as well as editor
  screen-should-contain [
    .                               run (F4)           .
    .                                                  .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
  # hit 'page-down'
  assume-console [
    press page-down
  ]
  run [
    event-loop screen, console, env, resources
  ]
  # sandbox editor hidden; first sandbox displayed
  # cursor moves to first sandbox
  screen-should-contain [
    .                               run (F4)           .
    .──────────────────────────────────────────────────.
    .0   edit           copy           delete          .  # no change
    .add 1, 1                                          .
    .2                                                 .
    .──────────────────────────────────────────────────.
    .                                                  .
  ]
]