mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-12-11 09:20:51 +00:00
10065010a6
* lisp/json.el (json-pretty-print): Improve pretty-printing of multiple JSON snippets in a region. Don't lose the region contents starting with the first non-JSON-parseable text. Also, don't swallow errors that occurred while parsing (bug#34160).
847 lines
29 KiB
EmacsLisp
847 lines
29 KiB
EmacsLisp
;;; json.el --- JavaScript Object Notation parser / generator -*- lexical-binding: t -*-
|
||
|
||
;; Copyright (C) 2006-2019 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 <https://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)
|
||
;; 2019-02-02 - Pretty-printing now uses replace-region-contents and support for
|
||
;; minimization -tsdh
|
||
|
||
;;; Code:
|
||
|
||
(require 'map)
|
||
(require 'subr-x)
|
||
|
||
;; 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.")
|
||
|
||
|
||
|
||
;;; 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
|
||
|
||
(define-inline json-advance (&optional n)
|
||
"Advance N characters forward."
|
||
(inline-quote (forward-char ,n)))
|
||
|
||
(define-inline json-peek ()
|
||
"Return the character at point."
|
||
(inline-quote (following-char)))
|
||
|
||
(define-inline json-pop ()
|
||
"Advance past the character at point, returning it."
|
||
(inline-quote
|
||
(let ((char (json-peek)))
|
||
(if (zerop char)
|
||
(signal 'json-end-of-file nil)
|
||
(json-advance)
|
||
char))))
|
||
|
||
(define-inline 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.
|
||
(inline-quote (skip-chars-forward "\t\r\n ")))
|
||
|
||
|
||
|
||
;; 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))
|
||
|
||
|
||
|
||
;;; 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)
|
||
(json-skip-whitespace)
|
||
(unless (looking-at "\\([],}]\\|$\\)")
|
||
(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."
|
||
(+ (ash (- 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
|
||
(or json-key-type
|
||
(cdr (assq json-object-type '((hash-table . string)
|
||
(alist . symbol)
|
||
(plist . keyword)))))))
|
||
(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 ((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)
|
||
"]")))
|
||
|
||
|
||
|
||
;;; 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 `((eq ,char ,c) (,@rest)) res))
|
||
`(cond ,@res (t (signal 'json-readtable-error (list ,char))))))
|
||
|
||
(defun json-read ()
|
||
"Parse and return the JSON object following point.
|
||
Advances point just past JSON object.
|
||
|
||
If called with the following JSON after point
|
||
|
||
{\"a\": [1, 2, {\"c\": false}],
|
||
\"b\": \"foo\"}
|
||
|
||
you will get the following structure returned:
|
||
|
||
((a .
|
||
[1 2
|
||
((c . :json-false))])
|
||
(b . \"foo\"))"
|
||
(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)))
|
||
|
||
|
||
|
||
;;; JSON encoder
|
||
|
||
(defun json-encode (object)
|
||
"Return a JSON representation of OBJECT as a string.
|
||
|
||
OBJECT should have a structure like one returned by `json-read'.
|
||
If an error is detected during encoding, an error based on
|
||
`json-error' is signalled."
|
||
(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)))
|
||
((listp object) (json-encode-list object))
|
||
((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))
|
||
(t (signal 'json-error (list object)))))
|
||
|
||
;; Pretty printing & minimizing
|
||
|
||
(defun json-pretty-print-buffer (&optional minimize)
|
||
"Pretty-print current buffer.
|
||
With prefix argument MINIMIZE, minimize it instead."
|
||
(interactive "P")
|
||
(json-pretty-print (point-min) (point-max) minimize))
|
||
|
||
(defvar json-pretty-print-max-secs 2.0
|
||
"Maximum time for `json-pretty-print's comparison.
|
||
The function `json-pretty-print' uses `replace-region-contents'
|
||
(which see) passing the value of this variable as argument
|
||
MAX-SECS.")
|
||
|
||
(defun json-pretty-print (begin end &optional minimize)
|
||
"Pretty-print selected region.
|
||
With prefix argument MINIMIZE, minimize it instead."
|
||
(interactive "r\nP")
|
||
(let ((json-encoding-pretty-print (null minimize))
|
||
;; Distinguish an empty objects from 'null'
|
||
(json-null :json-null)
|
||
;; Ensure that ordering is maintained
|
||
(json-object-type 'alist)
|
||
(orig-buf (current-buffer))
|
||
error)
|
||
;; Strategy: Repeatedly `json-read' from the original buffer and
|
||
;; write the pretty-printed snippet to a temporary buffer. As
|
||
;; soon as we get an error from `json-read', simply append the
|
||
;; remainder which we couldn't pretty-print to the temporary
|
||
;; buffer as well (probably the region ends _inside_ a JSON
|
||
;; object).
|
||
;;
|
||
;; Finally, use `replace-region-contents' to swap the original
|
||
;; region with the contents of the temporary buffer so that point,
|
||
;; marks, etc. are kept.
|
||
(with-temp-buffer
|
||
(let ((tmp-buf (current-buffer)))
|
||
(set-buffer orig-buf)
|
||
(replace-region-contents
|
||
begin end
|
||
(lambda ()
|
||
(let ((pos (point))
|
||
(keep-going t))
|
||
(while keep-going
|
||
(condition-case err
|
||
;; We want to format only the JSON snippets in the
|
||
;; region without modifying the whitespace between
|
||
;; them.
|
||
(let ((space (buffer-substring
|
||
(point)
|
||
(+ (point)
|
||
(skip-chars-forward
|
||
" \t\n" (point-max)))))
|
||
(json (json-read)))
|
||
(setq pos (point)) ; End of last good json-read.
|
||
(set-buffer tmp-buf)
|
||
(insert space (json-encode json))
|
||
(set-buffer orig-buf))
|
||
(t
|
||
(setq keep-going nil)
|
||
(set-buffer orig-buf)
|
||
;; Rescue the remainder we couldn't pretty-print.
|
||
(append-to-buffer tmp-buf pos (point-max))
|
||
;; EOF is expected because we json-read until we hit
|
||
;; the end of the narrow region.
|
||
(unless (eq (car err) 'json-end-of-file)
|
||
(setq error err)))))
|
||
tmp-buf))
|
||
json-pretty-print-max-secs
|
||
;; FIXME: What's a good value here? Can we use something better,
|
||
;; e.g., by deriving a value from the size of the region?
|
||
64)))
|
||
;; If we got an error during JSON processing (possibly the region
|
||
;; starts or ends inside a JSON object), signal it to the user.
|
||
;; We did our best.
|
||
(when error
|
||
(signal (car error) (cdr error)))))
|
||
|
||
(defun json-pretty-print-buffer-ordered (&optional minimize)
|
||
"Pretty-print current buffer with object keys ordered.
|
||
With prefix argument MINIMIZE, minimize it instead."
|
||
(interactive "P")
|
||
(let ((json-encoding-object-sort-predicate 'string<))
|
||
(json-pretty-print-buffer minimize)))
|
||
|
||
(defun json-pretty-print-ordered (begin end &optional minimize)
|
||
"Pretty-print the region with object keys ordered.
|
||
With prefix argument MINIMIZE, minimize it instead."
|
||
(interactive "r\nP")
|
||
(let ((json-encoding-object-sort-predicate 'string<))
|
||
(json-pretty-print begin end minimize)))
|
||
|
||
(provide 'json)
|
||
|
||
;;; json.el ends here
|