diff options
Diffstat (limited to 'lisp/json.el')
| -rw-r--r-- | lisp/json.el | 577 |
1 files changed, 288 insertions, 289 deletions
diff --git a/lisp/json.el b/lisp/json.el index ac323dac295..c2fc1574faa 100644 --- a/lisp/json.el +++ b/lisp/json.el @@ -3,7 +3,7 @@ ;; Copyright (C) 2006-2020 Free Software Foundation, Inc. ;; Author: Theresa O'Connor <ted@oconnor.cx> -;; Version: 1.4 +;; Version: 1.5 ;; Keywords: convenience ;; This file is part of GNU Emacs. @@ -29,11 +29,11 @@ ;; 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 +;; `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 +;; 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'). @@ -55,6 +55,7 @@ ;;; Code: (require 'map) +(require 'seq) (require 'subr-x) ;; Parameters @@ -113,8 +114,10 @@ Used only when `json-encoding-pretty-print' is non-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.") + "If non-nil, delimiters ] and } will be formatted Lisp-style. +This means they will be placed on the same line as the last +element of the respective array or object, without indentation. +Used only when `json-encoding-pretty-print' is non-nil.") (defvar json-encoding-object-sort-predicate nil "Sorting predicate for JSON object keys during encoding. @@ -124,88 +127,81 @@ 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.") + "If non-nil, a function to call before reading a JSON array or object. +It is called by `json-read-array' and `json-read-object', +respectively, 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.") + "If non-nil, a function to call after reading a JSON array or object. +It is called by `json-read-array' and `json-read-object', +respectively, with no arguments.") ;;; Utilities -(defun json-join (strings separator) - "Join STRINGS with SEPARATOR." - (mapconcat 'identity strings separator)) +(define-obsolete-function-alias 'json-join #'string-join "28.1") (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))) + "Non-nil if and only if LIST is an alist with simple keys." + (declare (pure t) (side-effect-free error-free)) + (while (and (consp (car-safe list)) + (atom (caar list)) + (setq list (cdr list)))) (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))) + "Non-nil if and only if LIST is a plist with keyword keys." + (declare (pure t) (side-effect-free error-free)) + (while (and (keywordp (car-safe list)) + (consp (cdr list)) + (setq list (cddr list)))) (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) +(defun json--plist-nreverse (plist) + "Return PLIST in reverse order. +Unlike `nreverse', this keeps the ordering of each property +relative to its value intact. Like `nreverse', this function may +destructively modify PLIST to produce the result." + (let (prev (next (cddr plist))) + (while next + (setcdr (cdr plist) prev) + (setq prev plist plist next next (cddr next)) + (setcdr (cdr plist) prev))) + plist) + +(defmacro json--with-indentation (&rest body) + "Evaluate BODY with the correct indentation for JSON encoding. +This macro binds `json--encoding-current-indentation' according +to `json-encoding-pretty-print' around BODY." + (declare (debug t) (indent 0)) `(let ((json--encoding-current-indentation (if json-encoding-pretty-print (concat json--encoding-current-indentation json-encoding-default-indentation) ""))) - ,body)) + ,@body)) ;; Reader utilities (define-inline json-advance (&optional n) - "Advance N characters forward." + "Advance N characters forward, or 1 character if N is nil. +On reaching the end of the accessible region of the buffer, stop +and signal an error." (inline-quote (forward-char ,n))) (define-inline json-peek () - "Return the character at point." + "Return the character at point. +At the end of the accessible region of the buffer, return 0." (inline-quote (following-char))) (define-inline json-pop () - "Advance past the character at point, returning it." + "Advance past the character at point, returning it. +Signal `json-end-of-file' if called at the end of the buffer." (inline-quote - (let ((char (json-peek))) - (if (zerop char) - (signal 'json-end-of-file nil) - (json-advance) - char)))) + (prog1 (or (char-after) + (signal 'json-end-of-file ())) + (json-advance)))) (define-inline json-skip-whitespace () "Skip past the whitespace at point." @@ -213,7 +209,7 @@ Unlike `reverse', this keeps the property-value pairs intact." ;; 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 "))) + (inline-quote (skip-chars-forward "\t\n\r "))) @@ -227,6 +223,7 @@ Unlike `reverse', this keeps the property-value pairs intact." (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-array-format "Bad JSON array" 'json-error) (define-error 'json-end-of-file "End of file while parsing JSON" '(end-of-file json-error)) @@ -235,8 +232,8 @@ Unlike `reverse', this keeps the property-value pairs intact." ;;; Paths (defvar json--path '() - "Used internally by `json-path-to-position' to keep track of -the path during recursive calls to `json-read'.") + "Keeps track of the path during recursive calls to `json-read'. +Used internally by `json-path-to-position'.") (defun json--record-path (key) "Record the KEY to the current JSON path. @@ -247,7 +244,7 @@ Used internally by `json-path-to-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)) + (when (< start position (1+ (point))) (throw :json-path (list :path (nreverse (mapcar #'cdr json--path)) :match-start start :match-end (point))))) @@ -265,13 +262,13 @@ 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. + indices. :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 +This can, for instance, be useful to determine the path to a JSON element in a deeply nested structure." (save-excursion (unless string @@ -279,7 +276,7 @@ element in a deeply nested structure." (let* ((json--path '()) (json-pre-element-read-function #'json--record-path) (json-post-element-read-function - (apply-partially #'json--check-position position)) + (lambda () (json--check-position position))) (path (catch :json-path (if string (json-read-from-string string) @@ -289,38 +286,33 @@ element in a deeply nested structure." ;;; Keywords -(defvar json-keywords '("true" "false" "null") +(defconst json-keywords '("true" "false" "null") "List of JSON keywords.") +(make-obsolete-variable 'json-keywords "it is no longer used." "28.1") ;; Keyword parsing +;; Characters that can follow a JSON value. +(rx-define json--post-value (| (in "\t\n\r ,]}") eos)) + (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))) + "Read the expected JSON KEYWORD at point." + (prog1 (cond ((equal keyword "true") t) + ((equal keyword "false") json-false) + ((equal keyword "null") json-null) + (t (signal 'json-unknown-keyword (list keyword)))) + (or (looking-at-p keyword) + (signal 'json-unknown-keyword (list (thing-at-point 'word)))) + (json-advance (length keyword)) + (or (looking-at-p (rx json--post-value)) + (signal 'json-unknown-keyword (list (thing-at-point 'word)))) + (json-skip-whitespace))) ;; Keyword encoding (defun json-encode-keyword (keyword) "Encode KEYWORD as a JSON value." + (declare (side-effect-free t)) (cond ((eq keyword t) "true") ((eq keyword json-false) "false") ((eq keyword json-null) "null"))) @@ -329,37 +321,31 @@ KEYWORD is the keyword expected." ;; 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))))))) +(rx-define json--number + (: (? ?-) ; Sign. + (| (: (in "1-9") (* digit)) ?0) ; Integer. + (? ?. (+ digit)) ; Fraction. + (? (in "Ee") (? (in ?+ ?-)) (+ digit)))) ; Exponent. + +(defun json-read-number (&optional _sign) + "Read the JSON number following point." + (declare (advertised-calling-convention () "28.1")) + (or (looking-at (rx json--number)) + (signal 'json-number-format (list (point)))) + (goto-char (match-end 0)) + (prog1 (string-to-number (match-string 0)) + (or (looking-at-p (rx json--post-value)) + (signal 'json-number-format (list (point)))) + (json-skip-whitespace))) ;; Number encoding -(defun json-encode-number (number) - "Return a JSON representation of NUMBER." - (format "%s" number)) +(defalias 'json-encode-number #'number-to-string + "Return a JSON representation of NUMBER.") ;;; Strings -(defvar json-special-chars +(defconst json-special-chars '((?\" . ?\") (?\\ . ?\\) (?b . ?\b) @@ -367,7 +353,7 @@ representation will be parsed correctly." (?n . ?\n) (?r . ?\r) (?t . ?\t)) - "Characters which are escaped in JSON, with their elisp counterparts.") + "Characters which are escaped in JSON, with their Elisp counterparts.") ;; String parsing @@ -377,48 +363,47 @@ representation will be parsed correctly." (defun json-read-escaped-char () "Read the JSON string escaped character at point." - ;; Skip over the '\' + ;; Skip over the '\'. (json-advance) - (let* ((char (json-pop)) - (special (assq char json-special-chars))) + (let ((char (json-pop))) (cond - (special (cdr special)) - ((not (eq char ?u)) char) + ((cdr (assq char json-special-chars))) + ((/= 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))))) + (rx (group (any "Dd") (any "89ABab") (= 2 xdigit)) + "\\u" (group (any "Dd") (any "C-Fc-f") (= 2 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))) + (json-advance 4) + (string-to-number (match-string 0) 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 '"' + ;; Skip over the '"'. (json-advance) (let ((characters '()) (char (json-peek))) - (while (not (= char ?\")) + (while (/= char ?\") (when (< char 32) - (signal 'json-string-format (list (prin1-char char)))) + (if (zerop char) + (signal 'json-end-of-file ()) + (signal 'json-string-format (list char)))) (push (if (= char ?\\) (json-read-escaped-char) - (json-pop)) + (json-advance) + char) characters) (setq char (json-peek))) - ;; Skip over the '"' + ;; Skip over the '"'. (json-advance) (if characters (concat (nreverse characters)) @@ -426,29 +411,47 @@ representation will be parsed correctly." ;; String encoding +;; Escape only quotation mark, backslash, and the control +;; characters U+0000 to U+001F (RFC 4627, ECMA-404). +(rx-define json--escape (in ?\" ?\\ cntrl)) + +(defvar json--long-string-threshold 200 + "Length above which strings are considered long for JSON encoding. +It is generally faster to manipulate such strings in a buffer +rather than directly.") + +(defvar json--string-buffer nil + "Buffer used for encoding Lisp strings as JSON. +Initialized lazily by `json-encode-string'.") + (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)))) + ;; Try to avoid buffer overhead in trivial cases, while also + ;; avoiding searching pathological strings for escape characters. + ;; Since `string-match-p' doesn't take a LIMIT argument, we use + ;; string length as our heuristic. See also bug#20154. + (if (and (< (length string) json--long-string-threshold) + (not (string-match-p (rx json--escape) string))) + (concat "\"" (substring-no-properties string) "\"") + (with-current-buffer + (or json--string-buffer + (with-current-buffer (generate-new-buffer " *json-string*") + ;; This seems to afford decent performance gains. + (setq-local inhibit-modification-hooks t) + (setq json--string-buffer (current-buffer)))) + (insert ?\" (substring-no-properties string)) ; see bug#43549 + (goto-char (1+ (point-min))) + (while (re-search-forward (rx json--escape) nil 'move) + (let ((char (preceding-char))) + (delete-char -1) + (insert ?\\ (or + ;; Special JSON character (\n, \r, etc.). + (car (rassq char json-special-chars)) + ;; Fallback: UCS code point in \uNNNN form. + (format "u%04x" char))))) + (insert ?\") + ;; Empty buffer for next invocation. + (delete-and-extract-region (point-min) (point-max))))) (defun json-encode-key (object) "Return a JSON representation of OBJECT. @@ -459,15 +462,13 @@ this signals `json-key-format'." (signal 'json-key-format (list object))) encoded)) -;;; JSON Objects +;;; Objects (defun json-new-object () - "Create a new Elisp object corresponding to a JSON object. + "Create a new Elisp object corresponding to an empty JSON object. Please see the documentation of `json-object-type'." - (cond ((eq json-object-type 'hash-table) - (make-hash-table :test 'equal)) - (t - ()))) + (and (eq json-object-type 'hash-table) + (make-hash-table :test #'equal))) (defun json-add-to-object (object key value) "Add a new KEY -> VALUE association to OBJECT. @@ -475,10 +476,10 @@ 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))))))) + (cond (json-key-type) + ((eq json-object-type 'hash-table) 'string) + ((eq json-object-type 'alist) 'symbol) + ((eq json-object-type 'plist) 'keyword)))) (setq key (cond ((eq json-key-type 'string) key) @@ -498,13 +499,13 @@ Please see the documentation of `json-object-type' and `json-key-type'." (defun json-read-object () "Read the JSON object at point." - ;; Skip over the "{" + ;; Skip over the '{'. (json-advance) (json-skip-whitespace) - ;; read key/value pairs until "}" + ;; Read key/value pairs until '}'. (let ((elements (json-new-object)) key value) - (while (not (= (json-peek) ?})) + (while (/= (json-peek) ?\}) (json-skip-whitespace) (setq key (json-read-string)) (json-skip-whitespace) @@ -519,94 +520,94 @@ Please see the documentation of `json-object-type' and `json-key-type'." (funcall json-post-element-read-function)) (setq elements (json-add-to-object elements key value)) (json-skip-whitespace) - (when (/= (json-peek) ?}) + (when (/= (json-peek) ?\}) (if (= (json-peek) ?,) (json-advance) (signal 'json-object-format (list "," (json-peek)))))) - ;; Skip over the "}" + ;; Skip over the '}'. (json-advance) (pcase json-object-type ('alist (nreverse elements)) - ('plist (json--plist-reverse elements)) + ('plist (json--plist-nreverse 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)))) + (cond ((hash-table-empty-p hash-table) "{}") + (json-encoding-object-sort-predicate + (json--encode-alist (map-pairs hash-table) t)) + (t + (let ((kv-sep (if json-encoding-pretty-print ": " ":")) + result) + (json--with-indentation + (maphash + (lambda (k v) + (push (concat json--encoding-current-indentation + (json-encode-key k) + kv-sep + (json-encode v)) + result)) + hash-table)) + (concat "{" + (string-join (nreverse result) json-encoding-separator) + (and json-encoding-pretty-print + (not 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." +(defun json--encode-alist (alist &optional destructive) + "Return a JSON representation of ALIST. +DESTRUCTIVE non-nil means it is safe to modify ALIST by +side-effects." (when json-encoding-object-sort-predicate - (setq alist - (sort alist (lambda (a b) + (setq alist (sort (if destructive alist (copy-sequence 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))) + (concat "{" + (let ((kv-sep (if json-encoding-pretty-print ": " ":"))) + (json--with-indentation + (mapconcat (lambda (cons) + (concat json--encoding-current-indentation + (json-encode-key (car cons)) + kv-sep + (json-encode (cdr cons)))) + alist + json-encoding-separator))) + (and json-encoding-pretty-print + (not json-encoding-lisp-style-closings) + json--encoding-current-indentation) + "}")) + +(defun json-encode-alist (alist) + "Return a JSON representation of ALIST." + (if alist (json--encode-alist alist) "{}")) (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))) + (cond ((null plist) "{}") + (json-encoding-object-sort-predicate + (json--encode-alist (map-pairs plist) t)) + (t + (let ((kv-sep (if json-encoding-pretty-print ": " ":")) 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 - "") - "}")))) + (json--with-indentation + (while plist + (push (concat json--encoding-current-indentation + (json-encode-key (pop plist)) + kv-sep + (json-encode (pop plist))) + result))) + (concat "{" + (string-join (nreverse result) json-encoding-separator) + (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. @@ -624,15 +625,17 @@ become JSON objects." (defun json-read-array () "Read the JSON array at point." - ;; Skip over the "[" + ;; Skip over the '['. (json-advance) (json-skip-whitespace) - ;; read values until "]" - (let (elements) - (while (not (= (json-peek) ?\])) + ;; Read values until ']'. + (let (elements + (len 0)) + (while (/= (json-peek) ?\]) (json-skip-whitespace) (when json-pre-element-read-function - (funcall json-pre-element-read-function (length elements))) + (funcall json-pre-element-read-function len) + (setq len (1+ len))) (push (json-read) elements) (when json-post-element-read-function (funcall json-post-element-read-function)) @@ -640,8 +643,8 @@ become JSON objects." (when (/= (json-peek) ?\]) (if (= (json-peek) ?,) (json-advance) - (signal 'json-error (list 'bleah))))) - ;; Skip over the "]" + (signal 'json-array-format (list "," (json-peek)))))) + ;; Skip over the ']'. (json-advance) (pcase json-array-type ('vector (nreverse (vconcat elements))) @@ -652,42 +655,43 @@ become JSON objects." (defun json-encode-array (array) "Return a JSON representation of ARRAY." (if (and json-encoding-pretty-print - (> (length array) 0)) + (not (seq-empty-p array))) (concat + "[" (json--with-indentation - (concat (format "[%s" json--encoding-current-indentation) - (json-join (mapcar 'json-encode array) - (format "%s%s" - json-encoding-separator + (concat json--encoding-current-indentation + (mapconcat #'json-encode array + (concat json-encoding-separator json--encoding-current-indentation)))) - (format "%s]" - (if json-encoding-lisp-style-closings - "" - json--encoding-current-indentation))) + (unless json-encoding-lisp-style-closings + json--encoding-current-indentation) + "]") (concat "[" - (mapconcat 'json-encode array json-encoding-separator) + (mapconcat #'json-encode array json-encoding-separator) "]"))) -;;; JSON reader. +;;; 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)))))) + "Dispatch reader function for CHAR at point. +If CHAR is nil, signal `json-end-of-file'." + (declare (debug t)) + (macroexp-let2 nil char char + `(cond ,@(map-apply + (lambda (key expr) + `((eq ,char ,key) ,expr)) + `((?\" ,#'json-read-string) + (?\[ ,#'json-read-array) + (?\{ ,#'json-read-object) + (?n ,#'json-read-keyword "null") + (?f ,#'json-read-keyword "false") + (?t ,#'json-read-keyword "true") + ,@(mapcar (lambda (c) (list c #'json-read-number)) + '(?- ?0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 ?9)))) + (,char (signal 'json-readtable-error (list ,char))) + (t (signal 'json-end-of-file ()))))) (defun json-read () "Parse and return the JSON object following point. @@ -705,10 +709,7 @@ you will get the following structure returned: ((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)))) + (json-readtable-dispatch (char-after))) ;; Syntactic sugar for the reader @@ -723,12 +724,11 @@ you will get the following structure returned: "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 +;;; Encoder (defun json-encode (object) "Return a JSON representation of OBJECT as a string. @@ -736,20 +736,21 @@ you will get the following structure returned: 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 signaled." - (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 + (cond ((eq object t) (json-encode-keyword object)) + ((eq object json-null) (json-encode-keyword object)) + ((eq object 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. @@ -768,9 +769,9 @@ MAX-SECS.") With prefix argument MINIMIZE, minimize it instead." (interactive "r\nP") (let ((json-encoding-pretty-print (null minimize)) - ;; Distinguish an empty objects from 'null' + ;; Distinguish an empty object from 'null'. (json-null :json-null) - ;; Ensure that ordering is maintained + ;; Ensure that ordering is maintained. (json-object-type 'alist) (orig-buf (current-buffer)) error) @@ -799,9 +800,7 @@ With prefix argument MINIMIZE, minimize it instead." ;; them. (let ((space (buffer-substring (point) - (+ (point) - (skip-chars-forward - " \t\n" (point-max))))) + (+ (point) (skip-chars-forward " \t\n")))) (json (json-read))) (setq pos (point)) ; End of last good json-read. (set-buffer tmp-buf) @@ -831,14 +830,14 @@ With prefix argument MINIMIZE, minimize it instead." "Pretty-print current buffer with object keys ordered. With prefix argument MINIMIZE, minimize it instead." (interactive "P") - (let ((json-encoding-object-sort-predicate 'string<)) + (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<)) + (let ((json-encoding-object-sort-predicate #'string<)) (json-pretty-print begin end minimize))) (provide 'json) |