File: racket-repl.el

package info (click to toggle)
racket-mode 20181003git0-2
  • links: PTS
  • area: main
  • in suites: buster
  • size: 732 kB
  • sloc: lisp: 7,641; makefile: 56
file content (746 lines) | stat: -rw-r--r-- 28,711 bytes parent folder | download
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
;;; racket-repl.el -*- lexical-binding: t; -*-

;; Copyright (c) 2013-2018 by Greg Hendershott.
;; Portions Copyright (C) 1985-1986, 1999-2013 Free Software Foundation, Inc.
;; Image portions Copyright (C) 2012 Jose Antonio Ortega Ruiz.

;; Author: Greg Hendershott
;; URL: https://github.com/greghendershott/racket-mode

;; License:
;; This is free software; you can redistribute it and/or modify it
;; under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version. This is distributed in the hope that it will be
;; useful, but without any warranty; without even the implied warranty
;; of merchantability or fitness for a particular purpose. See the GNU
;; General Public License for more details. See
;; http://www.gnu.org/licenses/ for details.

(require 'racket-custom)
(require 'racket-common)
(require 'racket-util)
(require 'comint)
(require 'compile)
(require 'easymenu)
(require 'cl-lib)

;; Don't (require 'racket-debug). Mutual dependency. Instead:
(declare-function  racket--debug-send-definition "racket-debug" (beg end))
(autoload         'racket--debug-send-definition "racket-debug")
(declare-function  racket--debug-on-break        "racket-debug" (response))
(autoload         'racket--debug-on-break        "racket-debug")
(declare-function  racket--debuggable-files      "racket-debug" (file-to-run))
(autoload         'racket--debuggable-files      "racket-debug")

(defconst racket--repl-buffer-name/raw
  "Racket REPL"
  "The base buffer name, NOT surrounded in *stars*")
(defconst racket--repl-buffer-name
  (concat "*" racket--repl-buffer-name/raw "*")
  "The actual buffer name as created by comint-mode")

(defmacro with-racket-repl-buffer (&rest body)
  "Execute the forms in BODY with `racket-repl-mode' temporarily current.
The value returned is the value of the last form in BODY --
unless no `racket-repl-mode' buffer exists, in which case no BODY
forms are evaluated and nil is returned. See also
`with-current-buffer'."
  (declare (indent 0) (debug t))
  (let ((repl-buffer (make-symbol "repl-buffer")))
    `(let ((,repl-buffer (get-buffer racket--repl-buffer-name)))
       (when ,repl-buffer
         (with-current-buffer ,repl-buffer
           ,@body)))))

(defun racket-repl--input-filter (str)
  "Don't save anything matching `racket-history-filter-regexp'."
  (not (string-match racket-history-filter-regexp str)))

(defalias 'racket-repl-eval-or-newline-and-indent #'racket-repl-submit)

(defun racket-repl-submit (&optional prefix)
  "Submit your input to the Racket REPL.

If the REPL is running a Racket lang whose language-info has a
'drracket:submit-predicate, that is first called to see if the
input is valid to be submitted.

With a prefix: After sending your input and a newline, also calls
`process-send-eof' -- because some langs require EOF to mark the
end of an interactive expression/statement."
  (interactive "P")
  (let* ((proc (get-buffer-process (current-buffer)))
         (_    (unless proc (user-error "Current buffer has no process")))
         (text (substring-no-properties (funcall comint-get-old-input))))
    (cl-case (if racket-use-repl-submit-predicate
                 (racket--cmd/await `(repl-submit? ,text t))
               'default)
      ((nil)
       (user-error "Not a complete expression, according to the current lang's submit-predicate."))
      ((t default)
       (comint-send-input)
       (remove-text-properties comint-last-input-start
                               comint-last-input-end
                               '(font-lock-face comint-highlight-input))
       ;; Hack for datalog/lang
       (when prefix (process-send-eof proc))))))

(defun racket-repl-exit (&optional quitp)
  "End the Racket REPL process.

Effectively the same as entering `(exit)` at the prompt, but
works even when the module language doesn't provide any binding
for `exit`.

With a prefix, uses `comint-quit-subjob' to send a quit signal."
  (interactive "P")
  (if quitp
      (comint-quit-subjob)
    (newline)
    (racket--cmd/async `(exit))))

;;;###autoload
(defun racket-repl (&optional noselect)
  "Run the Racket REPL and display its buffer in some window.

If the Racket process is not already running, it is started.

If NOSELECT is not nil, does not select the REPL
window (preserves the originally selected window).

Commands that don't want the REPL to be displayed can instead use
`racket--repl-ensure-buffer-and-process'."
  (interactive "P")
  (racket--repl-ensure-buffer-and-process t)
  (unless noselect
    (select-window (get-buffer-window racket--repl-buffer-name t))))

(defconst racket--minimum-required-version "6.0"
  "The minimum version of Racket required by run.rkt.

Although some functionality may require an even newer version of
Racket, run.rkt will handle that via `dynamic-require` and
fallbacks. The version number here is a baseline for run.rkt to
be able to load at all.")

(defvar racket--run.rkt (expand-file-name "run.rkt" racket--rkt-source-dir)
  "Pathname of run.rkt")

(defvar-local racket-user-command-line-arguments
  nil
  "List of command-line arguments to supply to your Racket program.

Accessible in your Racket program in the usual way -- the
parameter `current-command-line-arguments` and friends.

This is an Emacs buffer-local variable -- convenient to set as a
file local variable. For example at the end of your .rkt file:

    ;; Local Variables:
    ;; racket-user-command-line-arguments: (\"-f\" \"bar\")
    ;; End:

Set this way the value must be an unquoted list of strings such
as:

    (\"-f\" \"bar\")

but NOT:

    '(\"-f\" \"bar\")
    (list \"-f\" \"bar\")
")

(defun racket--repl-live-p ()
  "Does the Racket REPL buffer exist and have a live Racket process?"
  (comint-check-proc racket--repl-buffer-name))

(defvar racket--repl-before-run-hook nil
  "Thunks to do before each `racket--repl-run' -- except an initial run.")

(defun racket--repl-run (&optional what-to-run context-level callback)
  "Do an initial or subsequent run.

WHAT-TO-RUN should be a cons of a file name to a list of
submodule symbols. Or if nil, defaults to `racket--what-to-run'.

CONTEXT-LEVEL should be a valid value for the variable
`racket-error-context', 'coverage, or 'profile. Or if nil,
defaults to the variable `racket-error-context'.

CALLBACK is supplied to `racket--repl-run' and is used as the
callback for `racket--cmd/async'; it may be nil which is
equivalent to #'ignore.

- If the REPL is _not_ live, start our backend run.rkt passing
  the file to run as a command-line argument. The Emacs UI will
  _not_ be blocked during this.

- If the REPL _is_ live, send a run command to the backend's TCP
  server. If the server isn't live yet -- e.g. if Racket run.rkt
  are still starting up -- this _will_ block the Emacs UI."
  (let ((cmd (racket--repl-make-run-command (or what-to-run (racket--what-to-run))
                                            (or context-level racket-error-context))))
    (cond ((racket--repl-live-p)
           (run-hook-with-args 'racket--repl-before-run-hook)
           (racket--cmd/async cmd callback)
           (racket--repl-show-and-move-to-end))
          (t
           (when callback
             ;; Not sure how to do a callback, here, unless maybe
             ;; issuing a ``prompt` command?
             (message "Warning: run command callback ignored for startup run"))
           (racket--repl-ensure-buffer-and-process t cmd)))))

(defun racket--repl-make-run-command (what-to-run &optional context-level)
  "Form a `run` command sexpr for the backend.
WHAT-TO-RUN may be nil, meaning just a `racket/base` namespace."
  (let ((context-level (or context-level racket-error-context)))
    (list 'run
          what-to-run
          racket-memory-limit
          racket-pretty-print
          context-level
          racket-user-command-line-arguments
          (when (and what-to-run (eq context-level 'debug))
            (racket--debuggable-files (car what-to-run))))))

(defvar racket--cmd-auth nil
  "A value we give the Racket back-end when we launch it and when we connect.
See issue #327.")

(defun racket--repl-ensure-buffer-and-process (&optional display run-command)
  "Ensure Racket REPL buffer exists and has live Racket process.

If the Racket process is not already running, it is started and
the buffer is put in `racket-repl-mode'.

Non-nil DISPLAY means `display-buffer'.

Non-nil RUN-COMMAND is supplied as the second command-line
argument to `racket--run.rkt' so the process can start by
immediately running a desired file.

Never changes selected window."
  (if (racket--repl-live-p)
      (when display
        (display-buffer racket--repl-buffer-name))
    (racket--require-version racket--minimum-required-version)
    (with-current-buffer
        (make-comint racket--repl-buffer-name/raw ;w/o *stars*
                     racket-program
                     nil
                     racket--run.rkt
                     (number-to-string racket-command-port)
                     (setq racket--cmd-auth (format "%S\n" `(auth ,(random))))
                     (format "%S" (or run-command
                                      (racket--repl-make-run-command nil))))
      (let ((proc (get-buffer-process racket--repl-buffer-name)))
        ;; Display now so users see startup and banner sooner.
        (when display
          (display-buffer (current-buffer)))
        (message "Starting %s to run %s ..." racket-program racket--run.rkt)
        ;; Ensure command server connection closed when racket process dies.
        (set-process-sentinel proc
                              (lambda (_proc event)
                                (with-racket-repl-buffer
                                  (insert (concat "Process Racket REPL " event)))
                                (racket--cmd-disconnect)))
        (set-process-coding-system proc 'utf-8 'utf-8) ;for e.g. λ
        (racket-repl-mode))))
  (unless (racket--cmd-connected-or-connecting-p)
    (racket--cmd-connect-start)))

(defun racket--version ()
  "Get the `racket-program' version as a string."
  (with-temp-message "Checking Racket version ..."
    (with-temp-buffer
      (call-process racket-program nil t nil "--version")
      (goto-char (point-min))
      ;; Welcome to Racket v6.12.
      ;; Welcome to Racket v7.0.0.6.
      (save-match-data
        (re-search-forward "[0-9]+\\(?:\\.[0-9]+\\)*")
        (match-string 0)))))

(defun racket--require-version (at-least)
  "Raise a `user-error' unless Racket is version AT-LEAST."
  (let ((have (racket--version)))
    (unless (version<= at-least have)
      (user-error "racket-mode requires at least Racket version %s but you have %s"
                  at-least have))
    t))

;;; Connection to command process

(defvar racket--cmd-proc nil
  "Process when connection to the command server is established.")
(defvar racket--cmd-buf nil
  "Process buffer when connection to the command server is established.")
(defvar racket--cmd-connecting-p nil)

(defvar racket--cmd-nonce->callback (make-hash-table :test 'eq)
  "A hash from nonce to callback function.")
(defvar racket--cmd-nonce 0
  "Increments for each command request we send.")

(defvar racket--cmd-connect-attempts 15)
(defvar racket--cmd-connect-timeout 15)

(defun racket--cmd-connected-or-connecting-p ()
  (and (or racket--cmd-proc racket--cmd-connecting-p) t))

(defun racket--cmd-connect-start (&optional attempt)
  "Start to connect to the Racket command process.

If already connected, disconnects first.

The command server may might not be ready to accept connections,
because Racket itself and our backend are still starting up.
After calling this, call `racket--cmd-connect-finish' to
wait for the connection to be established."
  (unless (featurep 'make-network-process '(:nowait t))
    (error "racket-mode needs Emacs to support the :nowait feature"))
  (let ((attempt (or attempt 1)))
    (when (= attempt 1)
      (racket--cmd-disconnect)
      (setq racket--cmd-connecting-p t))
    (make-network-process
     :name    "racket-command"
     :host    "127.0.0.1"
     :service racket-command-port
     :nowait  t
     :sentinel
     (lambda (proc event)
       ;;(message "sentinel process %S event %S attempt %s" proc event attempt)
       (cond
        ((string-match-p "^open" event)
         (setq racket--cmd-proc proc)
         (setq racket--cmd-buf (generate-new-buffer
                                (concat " " (process-name proc))))
         (buffer-disable-undo racket--cmd-buf)
         (set-process-filter proc #'racket--cmd-process-filter)
         (process-send-string proc racket--cmd-auth)
         (message "Connected to %s process on port %s after %s attempt(s)"
                  proc racket-command-port attempt))
        ((string-match-p "^failed" event)
         (delete-process proc)
         (when (<= attempt racket--cmd-connect-attempts)
           (run-at-time 1.0 nil
                        #'racket--cmd-connect-start
                        (1+ attempt))))
        (t (racket--cmd-disconnect)))))))

(defun racket--cmd-connect-finish ()
  (with-timeout (racket--cmd-connect-timeout
                 (setq racket--cmd-connecting-p nil)
                 (error "Could not connect to racket-command process on port %s"
                        racket-command-port))
    (while (not racket--cmd-proc)
      (message "Still trying to connect to racket-command process on port %s ..."
               racket-command-port)
      (sit-for 0.2))
    (setq racket--cmd-connecting-p nil)))

(defun racket--cmd-disconnect ()
  "Disconnect from the Racket command process."
  (when racket--cmd-proc
    ;; Sentinel calls us for "deleted" event, which we ourselves will
    ;; trigger with the `delete-process' below. So set
    ;; racket--cmd-proc nil before calling `delete-process'.
    (let ((proc (prog1 racket--cmd-proc (setq racket--cmd-proc nil)))
          (buf  (prog1 racket--cmd-buf  (setq racket--cmd-buf nil))))
      (delete-process proc)
      (kill-buffer buf)
      (clrhash racket--cmd-nonce->callback)
      (setq racket--cmd-connecting-p nil))))

(defun racket--cmd-process-filter (_proc string)
  (let ((buffer racket--cmd-buf))
    (when (buffer-live-p buffer)
      (with-current-buffer buffer
        (goto-char (point-max))
        (insert string)
        (goto-char (point-min))
        (while
            (condition-case ()
                (progn
                  (forward-sexp 1)
                  (let ((sexp (buffer-substring (point-min) (point))))
                    (delete-region (point-min) (point))
                    (ignore-errors
                      (racket--cmd-dispatch-response (read sexp))
                      t)))
              (scan-error nil)))))))

(defun racket--cmd-dispatch-response (response)
  (pcase response
    (`(debug-break . ,response)
     (run-at-time 0.001 nil #'racket--debug-on-break response))
    (`(,nonce . ,response)
     (let ((callback (gethash nonce racket--cmd-nonce->callback)))
       (when callback
         (remhash nonce racket--cmd-nonce->callback)
         (run-at-time 0.001 nil callback response))))
    (_ nil)))

(defun racket--cmd/async-raw (command-sexpr &optional callback)
  "Send COMMAND-SEXPR and return. Later call CALLBACK with the response sexp.

If CALLBACK is not supplied or nil, defaults to `ignore'.

Otherwise CALLBACK is called after the command server returns a
response. Because command responses are obtained from the dynamic
extent of a `set-process-filter' proc -- which may have
limitations on what it can or should do -- CALLBACK is not called
immediately but instead using `run-at-time' with a very small
delay.

Important: Do not assume that `current-buffer' is the same when
CALLBACK is called, as it was when the command was sent. If you
need to do something to do that original buffer, save the
`current-buffer' in a `let' and use it in a `with-current-buffer'
form."
  (racket--repl-ensure-buffer-and-process nil)
  (racket--cmd-connect-finish)
  (cl-incf racket--cmd-nonce)
  (when (and callback
             (not (equal callback #'ignore)))
    (puthash racket--cmd-nonce callback racket--cmd-nonce->callback))
  (process-send-string racket--cmd-proc
                       (format "%S\n" (cons racket--cmd-nonce
                                            command-sexpr))))

(defun racket--cmd/async (command-sexpr &optional callback)
  "You probably want to use this instead of `racket--cmd/async-raw'.

CALLBACK is only called for 'ok responses, with (ok v ...)
unwrapped to (v ...).

'error responses are handled here. Note: We use `message' not
`error' here because:

  1. It would show \"error running timer:\" which, although true,
     is confusing or at best N/A for end users.

  2. More simply, we don't need to escape any call stack, we only
     need to ... not call the callback!

The original value of `current-buffer' is temporarily restored
during CALLBACK, because neglecting to do so is a likely
mistake."
  (let ((buf (current-buffer)))
    (racket--cmd/async-raw
     command-sexpr
     (if callback
         (lambda (response)
           (pcase response
             (`(ok ,v)    (with-current-buffer buf (funcall callback v)))
             (`(error ,m) (message "%s" m))
             (v           (message "Unknown command response: %S" v))))
       #'ignore))))

(defun racket--cmd/await (command-sexpr)
  "Send COMMAND-SEXPR. Await and return an 'ok response value, or raise `error'."
  (let* ((awaiting 'RACKET-REPL-AWAITING)
         (response awaiting))
    (racket--cmd/async-raw command-sexpr
                           (lambda (v) (setq response v)))
    (with-timeout (racket-command-timeout
                   (error "racket-command process timeout"))
      (while (eq response awaiting)
        (accept-process-output nil 0.001))
      (pcase response
        (`(ok ,v)    v)
        (`(error ,m) (error "%s" m))
        (v           (error "Unknown command response: %S" v))))))

;;; Misc

(defun racket-repl-file-name ()
  "Return the file running in the REPL, or nil.

The result can be nil if the REPL is not started, or if it is
running no particular file as with the `,top` command.

On Windows this will replace \ with / in an effort to match the
Unix style names used by Emacs on Windows."
  (when (comint-check-proc racket--repl-buffer-name)
    (pcase (racket--cmd/await `(path+md5))
      (`(,(and (pred stringp) path) . ,_md5)
       (cl-case system-type
         (windows-nt (subst-char-in-string ?\\ ?/ path))
         (otherwise  path)))
      (_ nil))))

(defun racket--in-repl-or-its-file-p ()
  "Is current-buffer `racket-repl-mode' or buffer for file active in it?"
  (or (eq (current-buffer)
          (get-buffer racket--repl-buffer-name))
      (string-equal (racket--buffer-file-name)
                    (racket-repl-file-name))))

(defun racket-repl-switch-to-edit ()
  "Switch to the window for the buffer of the file running in the REPL.

If no buffer is visting the file, `find-file' it in `other-window'.

If the REPL is running no file -- if the prompt is `>` -- use the
most recent `racket-mode' buffer, if any."
  (interactive)
  (pcase (racket-repl-file-name)
    (`() (let ((buffer (racket--most-recent-racket-mode-buffer)))
           (unless buffer
             (user-error "There are no racket-mode buffers"))
           (pop-to-buffer buffer t)))
    (path (let ((buffer (find-buffer-visiting path)))
            (if buffer
                (pop-to-buffer buffer t)
              (other-window 1)
              (find-file path))))))

(defun racket--most-recent-racket-mode-buffer ()
  (cl-some (lambda (b)
             (with-current-buffer b
               (and (eq major-mode 'racket-mode) b)))
           (buffer-list)))

;;; send to REPL

(defun racket--send-region-to-repl (start end)
  "Internal function to send the region to the Racket REPL.

Before sending the region, calls `racket-repl' and
`racket--repl-forget-errors'. Also inserts a ?\n at the process
mark so that output goes on a fresh line, not on the same line as
the prompt.

Afterwards call `racket--repl-show-and-move-to-end'."
  (when (and start end)
    (racket-repl t)
    (racket--repl-forget-errors)
    (let ((proc (get-buffer-process racket--repl-buffer-name)))
      (with-racket-repl-buffer
        (save-excursion
          (goto-char (process-mark proc))
          (insert ?\n)
          (set-marker (process-mark proc) (point))))
      (comint-send-region proc start end)
      (comint-send-string proc "\n"))
    (racket--repl-show-and-move-to-end)))

(defun racket-send-region (start end)
  "Send the current region (if any) to the Racket REPL."
  (interactive "r")
  (unless (region-active-p)
    (user-error "No region"))
  (racket--send-region-to-repl start end))

(defun racket-send-definition (&optional prefix)
  "Send the current definition to the Racket REPL."
  (interactive "P")
  (save-excursion
    (end-of-defun)
    (let ((end (point)))
      (beginning-of-defun)
      (if prefix
          (racket--debug-send-definition (point) end)
        (racket--send-region-to-repl (point) end)))))

(defun racket-send-last-sexp ()
  "Send the previous sexp to the Racket REPL.

When the previous sexp is a sexp comment the sexp itself is sent,
without the #; prefix."
  (interactive)
  (racket--send-region-to-repl (racket--repl-last-sexp-start)
                               (point)))

(defun racket-eval-last-sexp ()
  "Eval the previous sexp asynchronously and `message' the result."
  (interactive)
  (racket--cmd/async
   `(eval
     ,(buffer-substring-no-properties (racket--repl-last-sexp-start)
                                      (point)))
   (lambda (v)
     (message "%s" v))))

(defun racket--repl-last-sexp-start ()
  (save-excursion
    (condition-case ()
        (progn
          (backward-sexp)
          (if (save-match-data (looking-at "#;"))
              (+ (point) 2)
            (point)))
      (scan-error (user-error "There isn't a complete s-expression before point")))))

(defun racket--repl-forget-errors ()
  "Forget existing errors in the REPL.
Although they remain clickable they will be ignored by
`next-error' and `previous-error'"
  (with-racket-repl-buffer
    (compilation-forget-errors)
    ;; `compilation-forget-errors' may have just set
    ;; `compilation-messages-start' to a marker at position 1. But in
    ;; that case process output (including error messages) will be
    ;; inserted ABOVE the marker, in which case `next-error' won't see
    ;; them. Instead use a non-marker position like 1 or use nil.
    (when (and (markerp compilation-messages-start)
               (equal (marker-position compilation-messages-start) 1)
               (equal (marker-buffer compilation-messages-start) (current-buffer)))
      (setq compilation-messages-start nil))))

(add-hook 'racket--repl-before-run-hook #'racket--repl-forget-errors)

(defun racket--repl-show-and-move-to-end ()
  "Make the Racket REPL visible, and move point to end.
Keep original window selected."
  (display-buffer racket--repl-buffer-name)
  (save-selected-window
    (select-window (get-buffer-window racket--repl-buffer-name t))
    (comint-show-maximum-output)))

;;; Inline images in REPL

(defvar racket-image-cache-dir nil)

(defun racket-repl--list-image-cache ()
  "List all the images in the image cache."
  (and racket-image-cache-dir
       (file-directory-p racket-image-cache-dir)
       (let ((files (directory-files-and-attributes
                     racket-image-cache-dir t "racket-image-[0-9]*.png")))
         (mapcar #'car
                 (sort files (lambda (a b)
                               (< (float-time (nth 6 a))
                                  (float-time (nth 6 b)))))))))

(defun racket-repl--clean-image-cache ()
  "Clean all except for the last `racket-images-keep-last'
images in 'racket-image-cache-dir'."
  (interactive)
  (dolist (file (butlast (racket-repl--list-image-cache)
                         racket-images-keep-last))
    (delete-file file)))

(defun racket-repl--replace-images ()
  "Replace all image patterns with actual images"
  (with-silent-modifications
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward  "\"#<Image: \\(.+racket-image-.+\\.png\\)>\"" nil t)
        ;; can't pass a filename to create-image because emacs might
        ;; not display it before it gets deleted (race condition)
        (let* ((file (match-string 1))
               (begin (match-beginning 0))
               (end (match-end 0)))
          (delete-region begin end)
          (goto-char begin)
          (if (and racket-images-inline (display-images-p))
              (insert-image (create-image file) "[image]")
            (goto-char begin)
            (insert "[image] ; use M-x racket-view-last-image to view"))
          (setq racket-image-cache-dir (file-name-directory file))
          (racket-repl--clean-image-cache))))))

(defun racket-view-last-image (n)
  "Open the last displayed image using `racket-images-system-viewer'.

With prefix arg, open the N-th last shown image."
  (interactive "p")
  (let ((images (reverse (racket-repl--list-image-cache))))
    (if (>= (length images) n)
        (start-process "Racket image view"
                       nil
                       racket-images-system-viewer
                       (nth (- n 1) images))
      (error "There aren't %d recent images" n))))

(defun racket-repl--output-filter (_txt)
  (racket-repl--replace-images))

;;; racket-repl-mode

(defvar racket-repl-mode-map
  (racket--easy-keymap-define
   '(("C-m"             racket-repl-submit)
     ("C-j"             newline-and-indent)
     ("TAB"             indent-for-tab-command)
     ("C-M-u"           racket-backward-up-list)
     ("C-M-q"           prog-indent-sexp)
     ("C-a"             comint-bol)
     ("C-w"             comint-kill-region)
     ("[C-S-backspace]" comint-kill-whole-line)
     ("["               racket-smart-open-bracket)
     (")"               racket-insert-closing)
     ("]"               racket-insert-closing)
     ("}"               racket-insert-closing)
     ("C-c C-e f"       racket-expand-file)
     ("C-c C-e x"       racket-expand-definition)
     ("C-c C-e e"       racket-expand-last-sexp)
     ("C-c C-e r"       racket-expand-region)
     ("M-C-y"           racket-insert-lambda)
     ("C-c C-d"         racket-doc)
     ("C-c C-."         racket-describe)
     ("M-."             racket-visit-definition)
     ("C-M-."           racket-visit-module)
     ("M-,"             racket-unvisit)
     ("C-c C-z"         racket-repl-switch-to-edit)
     ("C-c C-l"         racket-logger)
     ("C-c C-\\"        racket-repl-exit)))
  "Keymap for Racket REPL mode.")

(easy-menu-define racket-repl-mode-menu racket-repl-mode-map
  "Menu for Racket REPL mode."
  '("Racket"
    ["Break" comint-interrupt-subjob]
    ["Exit" racket-repl-exit]
    "---"
    ["Insert Lambda" racket-insert-lambda] ;λ in string breaks menu
    ["Indent Region" indent-region]
    ["Cycle Paren Shapes" racket-cycle-paren-shapes]
    ("Macro Expand"
     ["File" racket-expand-file]
     ["Region" racket-expand-region  :active (region-active-p)]
     ["Definition" racket-expand-definition]
     ["Last S-Expression" racket-expand-last-sexp])
    "---"
    ["Visit Definition" racket-visit-definition]
    ["Visit Module" racket-visit-module]
    ["Return from Visit" racket-unvisit]
    "---"
    ["Racket Documentation" racket-doc]
    ["Describe" racket-describe]
    "---"
    ["Switch to Edit Buffer" racket-repl-switch-to-edit]))

(define-derived-mode racket-repl-mode comint-mode "Racket-REPL"
  "Major mode for Racket REPL.
\\{racket-repl-mode-map}"
  (racket--common-variables)
  (setq-local comint-use-prompt-regexp nil)
  (setq-local comint-prompt-read-only t)
  (setq-local comint-scroll-show-maximum-output nil) ;t slow for big outputs
  (setq-local mode-line-process nil)
  (setq-local comint-input-filter #'racket-repl--input-filter)
  (add-hook 'comint-output-filter-functions #'racket-repl--output-filter nil t)
  (compilation-setup t)
  (setq-local
   compilation-error-regexp-alist
   '(;; error
     ("^;?[ ]*\\([^ :]+\\):\\([0-9]+\\)[:.]\\([0-9]+\\)" 1 2 3)
     ;; contract
     ("^;?[ ]*at:[ ]+\\([^ :]+\\):\\([0-9]+\\)[.]\\([0-9]+\\)$" 1 2 3)
     ;; rackunit check-xxx
     ("#<path:\\([^>]+\\)> \\([0-9]+\\) \\([0-9]+\\)" 1 2 3)
     ;;rackunit/text-ui test-suite
     ("^location:[ ]+\\(\\([^:]+\\):\\([0-9]+\\):\\([0-9]+\\)\\)" 2 3 4 2 1)
     ;; path struct
     ("#<path:\\([^>]+\\)>" 1 nil nil 0))))

(provide 'racket-repl)

;; racket-repl.el ends here