[elpa] master ba07fd7: New package: json-mode

[Simen Heggestøyl]

branch: master
commit ba07fd786261ea2a588533887587258b2c796f40
Author: Simen Heggestøyl <address@hidden>
Commit: Simen Heggestøyl <address@hidden>

    New package: json-mode
---
 packages/json-mode/json-mode.el |  171 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)

diff --git a/packages/json-mode/json-mode.el b/packages/json-mode/json-mode.el
new file mode 100644
index 0000000..defaae0
--- /dev/null
+++ b/packages/json-mode/json-mode.el
@@ -0,0 +1,171 @@
+;;; json-mode.el --- Major mode for editing JSON files  -*- lexical-binding: 
t; -*-
+
+;; Copyright (C) 2015-2016 Free Software Foundation, Inc.
+
+;; Author: Simen Heggestøyl <address@hidden>
+;; Maintainer: Simen Heggestøyl <address@hidden>
+;; Version: 0.1
+;; Package-Requires: ((emacs "25.1"))
+;; Keywords: data
+
+;; This program 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.
+
+;; This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Major mode for editing JavaScript Object Notation (JSON) data files.
+;; Read more about JSON at http://json.org/.
+
+;; It provides support for indentation and syntax highlighting.
+
+;; Thanks to Josh Johnston for writing the original JSON mode!
+
+;;; Code:
+
+(require 'json)
+(require 'smie)
+
+(defgroup json-mode nil
+  "JavaScript Object Notation (JSON) editing mode."
+  :tag "JSON Mode"
+  :group 'data)
+
+(defcustom json-mode-indent-level 2
+  "Basic size of one indentation step."
+  :type 'integer)
+
+(defface json-mode-object-name-face
+  '((t :inherit font-lock-variable-name-face))
+  "Face to use for JSON object names.")
+
+(defvar json-mode-map
+  (let ((map (make-sparse-keymap "JSON")))
+    (define-key map "\C-c\C-f" #'json-mode-pretty-print-dwim)
+    (define-key map "\C-c\C-p" #'json-mode-show-path)
+    (easy-menu-define json-menu map "JSON mode menu"
+      `("JSON"
+        :help "JSON-specific features"
+        ["Pretty-print region" json-mode-pretty-print-dwim
+         :visible (region-active-p)]
+        ["Pretty-print buffer" json-mode-pretty-print-dwim
+         :visible (not (region-active-p))]
+        ["Show path" json-mode-show-path]))
+    map)
+  "Keymap used in JSON mode.")
+
+(defvar json-mode-syntax-table
+  (let ((st (make-syntax-table)))
+    ;; Objects
+    (modify-syntax-entry ?\{ "(}" st)
+    (modify-syntax-entry ?\} "){" st)
+    ;; Arrays
+    (modify-syntax-entry ?\[ "(]" st)
+    (modify-syntax-entry ?\] ")[" st)
+    ;; Strings
+    (modify-syntax-entry ?\" "\"" st)
+    ;; Comments
+    (modify-syntax-entry ?/ ". 12" st)
+    (modify-syntax-entry ?\n ">" st)
+    st))
+
+(defvar json-mode-font-lock-keywords
+  `(;; Constants
+    (,(concat "\\<" (regexp-opt json-keywords) "\\>")
+     (0 font-lock-constant-face))
+    ;; Object names
+    ("\\(\"[^\"]*\"\\)[[:blank:]]*:"
+     (1 'json-mode-object-name-face))
+    ;; Strings
+    ("\"\\(\\\\.\\|[^\"]\\)*\""
+     (0 font-lock-string-face))))
+
+(defun json-font-lock-syntactic-face-function (state)
+  "Highlight comments only.
+Strings are handled by `json-mode-font-lock-keywords', since we
+want to highlight object name strings differently from ordinary
+strings."
+  (when (nth 4 state) font-lock-comment-face))
+
+(defconst json-mode--smie-grammar
+  (smie-prec2->grammar
+   (smie-precs->prec2 '((assoc ",") (left ":")))))
+
+(defun json-mode--smie-rules (method arg)
+  "Provide indentation rules for METHOD given ARG.
+See the documentation of `smie-rules-function' for further
+information."
+  (pcase (cons method arg)
+    (`(:elem . basic) json-mode-indent-level)))
+
+(defun json-mode-pretty-print-dwim (&optional alphabetical)
+  "Pretty print region if active, else pretty print the buffer.
+`json-mode-indent-level' will be used as indentation offset.  If
+ALPHABETICAL is non-nil (interactively, with a prefix argument),
+JSON object members will be sorted alphabetically by their keys."
+  (interactive "P")
+  (let ((json-encoding-default-indentation
+         (make-string json-mode-indent-level ?\s)))
+    (if (use-region-p)
+        (funcall
+         (if alphabetical
+             'json-pretty-print-ordered
+           'json-pretty-print)
+         (region-beginning) (region-end))
+      (funcall
+       (if alphabetical
+           'json-pretty-print-buffer-ordered
+         'json-pretty-print-buffer)))))
+
+(defun json-mode-show-path ()
+  "Show the path to the JSON value under point.
+The value is also copied to the kill ring."
+  (interactive)
+  (let ((path (json-path-to-position (point))))
+    (if path
+        (let ((formatted-path
+               (json-mode--format-path (plist-get path :path))))
+          (when (fboundp 'pulse-momentary-highlight-region)
+            (pulse-momentary-highlight-region
+             (plist-get path :match-start)
+             (plist-get path :match-end)))
+          (message formatted-path)
+          (kill-new formatted-path))
+      (message "Not a JSON value"))))
+
+(defun json-mode--format-path (path)
+  "Return PATH formatted as a JSON data selector.
+PATH should be a list of keys, which can be either strings or
+integers."
+  (mapconcat (lambda (key) (format "[%S]" key)) path ""))
+
+;;;###autoload
+(add-to-list 'auto-mode-alist '("\\.json\\'" . json-mode))
+
+;;;###autoload
+(define-derived-mode json-mode prog-mode "JSON"
+  "Major mode for editing JavaScript Object Notation (JSON) data files."
+  (setq-local
+   font-lock-defaults
+   '(json-mode-font-lock-keywords
+     nil nil nil nil
+     (font-lock-syntactic-face-function
+      . json-font-lock-syntactic-face-function)))
+  ;; JSON has no comment syntax, but we set this to keep SMIE happy.
+  ;; Also, some JSON extensions allow comments.
+  (setq-local comment-start "// ")
+  (setq-local comment-end "")
+  (smie-setup json-mode--smie-grammar #'json-mode--smie-rules))
+
+(provide 'json-mode)
+
+;;; json-mode.el ends here