unofficial mirror of bug-gnu-emacs@gnu.org 
 help / color / mirror / code / Atom feed
blob fd2f63324c2d9d72f944f7b4e9aa997a21d7433c 26317 bytes (raw)
name: lisp/json.el 	 # note: path name is non-authoritative(*)

  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
 
;;; json.el --- JavaScript Object Notation parser / generator -*- lexical-binding: t -*-

;; Copyright (C) 2006-2017 Free Software Foundation, Inc.

;; Author: Theresa O'Connor <ted@oconnor.cx>
;; Version: 1.4
;; Keywords: convenience

;; This file is part of GNU Emacs.

;; GNU Emacs 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 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs 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.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This is a library for parsing and generating JSON (JavaScript Object
;; Notation).

;; Learn all about JSON here: <URL:http://json.org/>.

;; The user-serviceable entry points for the parser are the functions
;; `json-read' and `json-read-from-string'. The encoder has a single
;; entry point, `json-encode'.

;; Since there are several natural representations of key-value pair
;; mappings in elisp (alist, plist, hash-table), `json-read' allows you
;; to specify which you'd prefer (see `json-object-type' and
;; `json-array-type').

;; Similarly, since `false' and `null' are distinct in JSON, you can
;; distinguish them by binding `json-false' and `json-null' as desired.

;;; History:

;; 2006-03-11 - Initial version.
;; 2006-03-13 - Added JSON generation in addition to parsing. Various
;;              other cleanups, bugfixes, and improvements.
;; 2006-12-29 - XEmacs support, from Aidan Kehoe <kehoea@parhasard.net>.
;; 2008-02-21 - Installed in GNU Emacs.
;; 2011-10-17 - Patch `json-alist-p' and `json-plist-p' to avoid recursion -tzz
;; 2012-10-25 - Added pretty-printed reformatting -Ryan Crum (ryan@ryancrum.org)

;;; Code:

(require 'map)

;; Parameters

(defvar json-object-type 'alist
  "Type to convert JSON objects to.
Must be one of `alist', `plist', or `hash-table'.  Consider let-binding
this around your call to `json-read' instead of `setq'ing it.  Ordering
is maintained for `alist' and `plist', but not for `hash-table'.")

(defvar json-array-type 'vector
  "Type to convert JSON arrays to.
Must be one of `vector' or `list'.  Consider let-binding this around
your call to `json-read' instead of `setq'ing it.")

(defvar json-key-type nil
  "Type to convert JSON keys to.
Must be one of `string', `symbol', `keyword', or nil.

If nil, `json-read' will guess the type based on the value of
`json-object-type':

    If `json-object-type' is:   nil will be interpreted as:
      `hash-table'                `string'
      `alist'                     `symbol'
      `plist'                     `keyword'

Note that values other than `string' might behave strangely for
Sufficiently Weird keys.  Consider let-binding this around your call to
`json-read' instead of `setq'ing it.")

(defvar json-false :json-false
  "Value to use when reading JSON `false'.
If this has the same value as `json-null', you might not be able to tell
the difference between `false' and `null'.  Consider let-binding this
around your call to `json-read' instead of `setq'ing it.")

(defvar json-null nil
  "Value to use when reading JSON `null'.
If this has the same value as `json-false', you might not be able to
tell the difference between `false' and `null'.  Consider let-binding
this around your call to `json-read' instead of `setq'ing it.")

(defvar json-encoding-separator ","
  "Value to use as an element separator when encoding.")

(defvar json-encoding-default-indentation "  "
  "The default indentation level for encoding.
Used only when `json-encoding-pretty-print' is non-nil.")

(defvar json--encoding-current-indentation "\n"
  "Internally used to keep track of the current indentation level of encoding.
Used only when `json-encoding-pretty-print' is non-nil.")

(defvar json-encoding-pretty-print nil
  "If non-nil, then the output of `json-encode' will be pretty-printed.")

(defvar json-encoding-lisp-style-closings nil
  "If non-nil, ] and } closings will be formatted lisp-style,
without indentation.")

(defvar json-encoding-object-sort-predicate nil
  "Sorting predicate for JSON object keys during encoding.
If nil, no sorting is performed.  Else, JSON object keys are
ordered by the specified sort predicate during encoding.  For
instance, setting this to `string<' will have JSON object keys
ordered alphabetically.")

(defvar json-pre-element-read-function nil
  "Function called (if non-nil) by `json-read-array' and
`json-read-object' right before reading a JSON array or object,
respectively.  The function is called with one argument, which is
the current JSON key.")

(defvar json-post-element-read-function nil
  "Function called (if non-nil) by `json-read-array' and
`json-read-object' right after reading a JSON array or object,
respectively.")

\f

;;; Utilities

(defun json-join (strings separator)
  "Join STRINGS with SEPARATOR."
  (mapconcat 'identity strings separator))

(defun json-alist-p (list)
  "Non-null if and only if LIST is an alist with simple keys."
  (while (consp list)
    (setq list (if (and (consp (car list))
                        (atom (caar list)))
                   (cdr list)
                 'not-alist)))
  (null list))

(defun json-plist-p (list)
  "Non-null if and only if LIST is a plist with keyword keys."
  (while (consp list)
    (setq list (if (and (keywordp (car list))
                        (consp (cdr list)))
                   (cddr list)
                 'not-plist)))
  (null list))

(defun json--plist-reverse (plist)
  "Return a copy of PLIST in reverse order.
Unlike `reverse', this keeps the property-value pairs intact."
  (let (res)
    (while plist
      (let ((prop (pop plist))
            (val (pop plist)))
        (push val res)
        (push prop res)))
    res))

(defun json--plist-to-alist (plist)
  "Return an alist of the property-value pairs in PLIST."
  (let (res)
    (while plist
      (let ((prop (pop plist))
            (val (pop plist)))
        (push (cons prop val) res)))
    (nreverse res)))

(defmacro json--with-indentation (body)
  `(let ((json--encoding-current-indentation
          (if json-encoding-pretty-print
              (concat json--encoding-current-indentation
                      json-encoding-default-indentation)
            "")))
     ,body))

;; Reader utilities

(defsubst json-advance (&optional n)
  "Advance N characters forward."
  (forward-char n))

(defsubst json-peek ()
  "Return the character at point."
  (following-char))

(defsubst json-pop ()
  "Advance past the character at point, returning it."
  (let ((char (json-peek)))
    (if (zerop char)
        (signal 'json-end-of-file nil)
      (json-advance)
      char)))

(defun json-skip-whitespace ()
  "Skip past the whitespace at point."
  ;; See
  ;; https://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf
  ;; or https://tools.ietf.org/html/rfc7159#section-2 for the
  ;; definition of whitespace in JSON.
  (skip-chars-forward "\t\r\n "))

\f

;; Error conditions

(define-error 'json-error "Unknown JSON error")
(define-error 'json-readtable-error "JSON readtable error" 'json-error)
(define-error 'json-unknown-keyword "Unrecognized keyword" 'json-error)
(define-error 'json-number-format "Invalid number format" 'json-error)
(define-error 'json-string-escape "Bad Unicode escape" 'json-error)
(define-error 'json-string-format "Bad string format" 'json-error)
(define-error 'json-key-format "Bad JSON object key" 'json-error)
(define-error 'json-object-format "Bad JSON object" 'json-error)
(define-error 'json-end-of-file "End of file while parsing JSON"
  '(end-of-file json-error))

\f

;;; Paths

(defvar json--path '()
  "Used internally by `json-path-to-position' to keep track of
the path during recursive calls to `json-read'.")

(defun json--record-path (key)
  "Record the KEY to the current JSON path.
Used internally by `json-path-to-position'."
  (push (cons (point) key) json--path))

(defun json--check-position (position)
  "Check if the last parsed JSON structure passed POSITION.
Used internally by `json-path-to-position'."
  (let ((start (caar json--path)))
    (when (< start position (+ (point) 1))
      (throw :json-path (list :path (nreverse (mapcar #'cdr json--path))
                              :match-start start
                              :match-end (point)))))
  (pop json--path))

(defun json-path-to-position (position &optional string)
  "Return the path to the JSON element at POSITION.

When STRING is provided, return the path to the position in the
string, else to the position in the current buffer.

The return value is a property list with the following
properties:

:path        -- A list of strings and numbers forming the path to
                the JSON element at the given position.  Strings
                denote object names, while numbers denote array
                indexes.

:match-start -- Position where the matched JSON element begins.

:match-end   -- Position where the matched JSON element ends.

This can for instance be useful to determine the path to a JSON
element in a deeply nested structure."
  (save-excursion
    (unless string
      (goto-char (point-min)))
    (let* ((json--path '())
           (json-pre-element-read-function #'json--record-path)
           (json-post-element-read-function
            (apply-partially #'json--check-position position))
           (path (catch :json-path
                   (if string
                       (json-read-from-string string)
                     (json-read)))))
      (when (plist-get path :path)
        path))))

;;; Keywords

(defvar json-keywords '("true" "false" "null")
  "List of JSON keywords.")

;; Keyword parsing

(defun json-read-keyword (keyword)
  "Read a JSON keyword at point.
KEYWORD is the keyword expected."
  (unless (member keyword json-keywords)
    (signal 'json-unknown-keyword (list keyword)))
  (mapc (lambda (char)
          (when (/= char (json-peek))
            (signal 'json-unknown-keyword
                    (list (save-excursion
                            (backward-word-strictly 1)
                            (thing-at-point 'word)))))
          (json-advance))
        keyword)
  (unless (looking-at "\\(\\s-\\|[],}]\\|$\\)")
    (signal 'json-unknown-keyword
            (list (save-excursion
                    (backward-word-strictly 1)
                    (thing-at-point 'word)))))
  (cond ((string-equal keyword "true") t)
        ((string-equal keyword "false") json-false)
        ((string-equal keyword "null") json-null)))

;; Keyword encoding

(defun json-encode-keyword (keyword)
  "Encode KEYWORD as a JSON value."
  (cond ((eq keyword t)          "true")
        ((eq keyword json-false) "false")
        ((eq keyword json-null)  "null")))

;;; Numbers

;; Number parsing

(defun json-read-number (&optional sign)
 "Read the JSON number following point.
The optional SIGN argument is for internal use.

N.B.: Only numbers which can fit in Emacs Lisp's native number
representation will be parsed correctly."
 ;; If SIGN is non-nil, the number is explicitly signed.
 (let ((number-regexp
        "\\([0-9]+\\)?\\(\\.[0-9]+\\)?\\([Ee][+-]?[0-9]+\\)?"))
   (cond ((and (null sign) (= (json-peek) ?-))
          (json-advance)
          (- (json-read-number t)))
         ((and (null sign) (= (json-peek) ?+))
          (json-advance)
          (json-read-number t))
         ((and (looking-at number-regexp)
               (or (match-beginning 1)
                   (match-beginning 2)))
          (goto-char (match-end 0))
          (string-to-number (match-string 0)))
         (t (signal 'json-number-format (list (point)))))))

;; Number encoding

(defun json-encode-number (number)
  "Return a JSON representation of NUMBER."
  (format "%s" number))

;;; Strings

(defvar json-special-chars
  '((?\" . ?\")
    (?\\ . ?\\)
    (?b . ?\b)
    (?f . ?\f)
    (?n . ?\n)
    (?r . ?\r)
    (?t . ?\t))
  "Characters which are escaped in JSON, with their elisp counterparts.")

;; String parsing

(defun json--decode-utf-16-surrogates (high low)
  "Return the code point represented by the UTF-16 surrogates HIGH and LOW."
  (+ (lsh (- high #xD800) 10) (- low #xDC00) #x10000))

(defun json-read-escaped-char ()
  "Read the JSON string escaped character at point."
  ;; Skip over the '\'
  (json-advance)
  (let* ((char (json-pop))
         (special (assq char json-special-chars)))
    (cond
     (special (cdr special))
     ((not (eq char ?u)) char)
     ;; Special-case UTF-16 surrogate pairs,
     ;; cf. <https://tools.ietf.org/html/rfc7159#section-7>.  Note that
     ;; this clause overlaps with the next one and therefore has to
     ;; come first.
     ((looking-at
       (rx (group (any "Dd") (any "89ABab") (= 2 (any xdigit)))
           "\\u" (group (any "Dd") (any "C-Fc-f") (= 2 (any xdigit)))))
      (json-advance 10)
      (json--decode-utf-16-surrogates
       (string-to-number (match-string 1) 16)
       (string-to-number (match-string 2) 16)))
     ((looking-at (rx (= 4 xdigit)))
      (let ((hex (match-string 0)))
        (json-advance 4)
        (string-to-number hex 16)))
     (t
      (signal 'json-string-escape (list (point)))))))

(defun json-read-string ()
  "Read the JSON string at point."
  (unless (= (json-peek) ?\")
    (signal 'json-string-format (list "doesn't start with `\"'!")))
  ;; Skip over the '"'
  (json-advance)
  (let ((characters '())
        (char (json-peek)))
    (while (not (= char ?\"))
      (when (< char 32)
        (signal 'json-string-format (list (prin1-char char))))
      (push (if (= char ?\\)
                (json-read-escaped-char)
              (json-pop))
            characters)
      (setq char (json-peek)))
    ;; Skip over the '"'
    (json-advance)
    (if characters
        (concat (nreverse characters))
      "")))

;; String encoding

(defun json-encode-string (string)
  "Return a JSON representation of STRING."
  ;; Reimplement the meat of `replace-regexp-in-string', for
  ;; performance (bug#20154).
  (let ((l (length string))
        (start 0)
        res mb)
    ;; Only escape quotation mark, backslash and the control
    ;; characters U+0000 to U+001F (RFC 4627, ECMA-404).
    (while (setq mb (string-match "[\"\\[:cntrl:]]" string start))
      (let* ((c (aref string mb))
             (special (rassq c json-special-chars)))
        (push (substring string start mb) res)
        (push (if special
                  ;; Special JSON character (\n, \r, etc.).
                  (string ?\\ (car special))
                ;; Fallback: UCS code point in \uNNNN form.
                (format "\\u%04x" c))
              res)
        (setq start (1+ mb))))
    (push (substring string start l) res)
    (push "\"" res)
    (apply #'concat "\"" (nreverse res))))

(defun json-encode-key (object)
  "Return a JSON representation of OBJECT.
If the resulting JSON object isn't a valid JSON object key,
this signals `json-key-format'."
  (let ((encoded (json-encode object)))
    (unless (stringp (json-read-from-string encoded))
      (signal 'json-key-format (list object)))
    encoded))

;;; JSON Objects

(defun json-new-object ()
  "Create a new Elisp object corresponding to a JSON object.
Please see the documentation of `json-object-type'."
  (cond ((eq json-object-type 'hash-table)
         (make-hash-table :test 'equal))
        (t
         ())))

(defun json-add-to-object (object key value)
  "Add a new KEY -> VALUE association to OBJECT.
Returns the updated object, which you should save, e.g.:
    (setq obj (json-add-to-object obj \"foo\" \"bar\"))
Please see the documentation of `json-object-type' and `json-key-type'."
  (let ((json-key-type
         (if (eq json-key-type nil)
             (cdr (assq json-object-type '((hash-table . string)
                                           (alist . symbol)
                                           (plist . keyword))))
           json-key-type)))
    (setq key
          (cond ((eq json-key-type 'string)
                 key)
                ((eq json-key-type 'symbol)
                 (intern key))
                ((eq json-key-type 'keyword)
                 (intern (concat ":" key)))))
    (cond ((eq json-object-type 'hash-table)
           (puthash key value object)
           object)
          ((eq json-object-type 'alist)
           (cons (cons key value) object))
          ((eq json-object-type 'plist)
           (cons key (cons value object))))))

;; JSON object parsing

(defun json-read-object ()
  "Read the JSON object at point."
  ;; Skip over the "{"
  (json-advance)
  (json-skip-whitespace)
  ;; read key/value pairs until "}"
  (let ((elements (json-new-object))
        key value)
    (while (not (= (json-peek) ?}))
      (json-skip-whitespace)
      (setq key (json-read-string))
      (json-skip-whitespace)
      (if (= (json-peek) ?:)
          (json-advance)
        (signal 'json-object-format (list ":" (json-peek))))
      (json-skip-whitespace)
      (when json-pre-element-read-function
        (funcall json-pre-element-read-function key))
      (setq value (json-read))
      (when json-post-element-read-function
        (funcall json-post-element-read-function))
      (setq elements (json-add-to-object elements key value))
      (json-skip-whitespace)
      (when (/= (json-peek) ?})
        (if (= (json-peek) ?,)
            (json-advance)
          (signal 'json-object-format (list "," (json-peek))))))
    ;; Skip over the "}"
    (json-advance)
    (pcase json-object-type
      (`alist (nreverse elements))
      (`plist (json--plist-reverse elements))
      (_ elements))))

;; Hash table encoding

(defun json-encode-hash-table (hash-table)
  "Return a JSON representation of HASH-TABLE."
  (if json-encoding-object-sort-predicate
      (json-encode-alist (map-into hash-table 'list))
    (format "{%s%s}"
            (json-join
             (let (r)
               (json--with-indentation
                (maphash
                 (lambda (k v)
                   (push (format
                          (if json-encoding-pretty-print
                              "%s%s: %s"
                            "%s%s:%s")
                          json--encoding-current-indentation
                          (json-encode-key k)
                          (json-encode v))
                         r))
                 hash-table))
               r)
             json-encoding-separator)
            (if (or (not json-encoding-pretty-print)
                    json-encoding-lisp-style-closings)
                ""
              json--encoding-current-indentation))))

;; List encoding (including alists and plists)

(defun json-encode-alist (alist)
  "Return a JSON representation of ALIST."
  (when json-encoding-object-sort-predicate
    (setq alist
          (sort alist (lambda (a b)
                        (funcall json-encoding-object-sort-predicate
                                 (car a) (car b))))))
  (format "{%s%s}"
          (json-join
           (json--with-indentation
            (mapcar (lambda (cons)
                      (format (if json-encoding-pretty-print
                                  "%s%s: %s"
                                "%s%s:%s")
                              json--encoding-current-indentation
                              (json-encode-key (car cons))
                              (json-encode (cdr cons))))
                    alist))
           json-encoding-separator)
          (if (or (not json-encoding-pretty-print)
                  json-encoding-lisp-style-closings)
              ""
            json--encoding-current-indentation)))

(defun json-encode-plist (plist)
  "Return a JSON representation of PLIST."
  (if json-encoding-object-sort-predicate
      (json-encode-alist (json--plist-to-alist plist))
    (let (result)
      (json--with-indentation
       (while plist
         (push (concat
                json--encoding-current-indentation
                (json-encode-key (car plist))
                (if json-encoding-pretty-print
                    ": "
                  ":")
                (json-encode (cadr plist)))
               result)
         (setq plist (cddr plist))))
      (concat "{"
              (json-join (nreverse result) json-encoding-separator)
              (if (and json-encoding-pretty-print
                       (not json-encoding-lisp-style-closings))
                  json--encoding-current-indentation
                "")
              "}"))))

(defun json-encode-list (list)
  "Return a JSON representation of LIST.
Tries to DWIM: simple lists become JSON arrays, while alists and plists
become JSON objects."
  (cond ((null list)         "null")
        ((json-alist-p list) (json-encode-alist list))
        ((json-plist-p list) (json-encode-plist list))
        ((listp list)        (json-encode-array list))
        (t
         (signal 'json-error (list list)))))

;;; Arrays

;; Array parsing

(defun json-read-array ()
  "Read the JSON array at point."
  ;; Skip over the "["
  (json-advance)
  (json-skip-whitespace)
  ;; read values until "]"
  (let (elements)
    (while (not (= (json-peek) ?\]))
      (json-skip-whitespace)
      (when json-pre-element-read-function
        (funcall json-pre-element-read-function (length elements)))
      (push (json-read) elements)
      (when json-post-element-read-function
        (funcall json-post-element-read-function))
      (json-skip-whitespace)
      (when (/= (json-peek) ?\])
        (if (= (json-peek) ?,)
            (json-advance)
          (signal 'json-error (list 'bleah)))))
    ;; Skip over the "]"
    (json-advance)
    (pcase json-array-type
      (`vector (nreverse (vconcat elements)))
      (`list (nreverse elements)))))

;; Array encoding

(defun json-encode-array (array)
  "Return a JSON representation of ARRAY."
  (if (and json-encoding-pretty-print
           (> (length array) 0))
      (concat
       (json--with-indentation
         (concat (format "[%s" json--encoding-current-indentation)
                 (json-join (mapcar 'json-encode array)
                            (format "%s%s"
                                    json-encoding-separator
                                    json--encoding-current-indentation))))
       (format "%s]"
               (if json-encoding-lisp-style-closings
                   ""
                 json--encoding-current-indentation)))
    (concat "["
            (mapconcat 'json-encode array json-encoding-separator)
            "]")))

\f

;;; JSON reader.

(defvar json-readtable
  (let ((table
         '((?t json-read-keyword "true")
           (?f json-read-keyword "false")
           (?n json-read-keyword "null")
           (?{ json-read-object)
           (?\[ json-read-array)
           (?\" json-read-string))))
    (mapc (lambda (char)
            (push (list char 'json-read-number) table))
          '(?- ?+ ?. ?0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 ?9))
    table)
  "Readtable for JSON reader.")

(defmacro json-readtable-dispatch (char)
  "Dispatch reader function for CHAR."
  (declare (debug (symbolp)))
  (let ((table
         '((?t json-read-keyword "true")
           (?f json-read-keyword "false")
           (?n json-read-keyword "null")
           (?{ json-read-object)
           (?\[ json-read-array)
           (?\" json-read-string)))
        res)
    (dolist (c '(?- ?+ ?. ?0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 ?9))
      (push (list c 'json-read-number) table))
    (pcase-dolist (`(,c . ,rest) table)
      (push `(,c (,@rest)) res))
    `(pcase ,char ,@res (_ (signal 'json-readtable-error ,char)))))

(defun json-read ()
  "Parse and return the JSON object following point.
Advances point just past JSON object."
  (json-skip-whitespace)
  (let ((char (json-peek)))
    (if (zerop char)
        (signal 'json-end-of-file nil)
      (json-readtable-dispatch char))))

;; Syntactic sugar for the reader

(defun json-read-from-string (string)
  "Read the JSON object contained in STRING and return it."
  (with-temp-buffer
    (insert string)
    (goto-char (point-min))
    (json-read)))

(defun json-read-file (file)
  "Read the first JSON object contained in FILE and return it."
  (with-temp-buffer
    (insert-file-contents file)
    (goto-char (point-min))
    (json-read)))

\f

;;; JSON encoder

(defun json-encode (object)
  "Return a JSON representation of OBJECT as a string."
  (cond ((memq object (list t json-null json-false))
         (json-encode-keyword object))
        ((stringp object)      (json-encode-string object))
        ((keywordp object)     (json-encode-string
                                (substring (symbol-name object) 1)))
        ((symbolp object)      (json-encode-string
                                (symbol-name object)))
        ((numberp object)      (json-encode-number object))
        ((arrayp object)       (json-encode-array object))
        ((hash-table-p object) (json-encode-hash-table object))
        ((listp object)        (json-encode-list object))
        (t                     (signal 'json-error (list object)))))

;; Pretty printing

(defun json-pretty-print-buffer ()
  "Pretty-print current buffer."
  (interactive)
  (json-pretty-print (point-min) (point-max)))

(defun json-pretty-print (begin end)
  "Pretty-print selected region."
  (interactive "r")
  (atomic-change-group
    (let ((json-encoding-pretty-print t)
          ;; Ensure that ordering is maintained
          (json-object-type 'alist)
          (txt (delete-and-extract-region begin end)))
      (insert (json-encode (json-read-from-string txt))))))

(defun json-pretty-print-buffer-ordered ()
  "Pretty-print current buffer with object keys ordered."
  (interactive)
  (let ((json-encoding-object-sort-predicate 'string<))
    (json-pretty-print-buffer)))

(defun json-pretty-print-ordered (begin end)
  "Pretty-print the region with object keys ordered."
  (interactive "r")
  (let ((json-encoding-object-sort-predicate 'string<))
    (json-pretty-print begin end)))

(provide 'json)

;;; json.el ends here

debug log:

solving fd2f63324c ...
found fd2f63324c in https://yhetil.org/emacs-bugs/8737812hqc.fsf@holos/
found 64486258cc in https://git.savannah.gnu.org/cgit/emacs.git
preparing index
index prepared:
100644 64486258ccf58b4469f0928afd82fc69382dcbd3	lisp/json.el

applying [1/1] https://yhetil.org/emacs-bugs/8737812hqc.fsf@holos/
diff --git a/lisp/json.el b/lisp/json.el
index 64486258cc..fd2f63324c 100644

Checking patch lisp/json.el...
Applied patch lisp/json.el cleanly.

index at:
100644 fd2f63324c2d9d72f944f7b4e9aa997a21d7433c	lisp/json.el

(*) Git path names are given by the tree(s) the blob belongs to.
    Blobs themselves have no identifier aside from the hash of its contents.^

Code repositories for project(s) associated with this public inbox

	https://git.savannah.gnu.org/cgit/emacs.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).