352 lines
14 KiB
EmacsLisp
352 lines
14 KiB
EmacsLisp
;;; json-snatcher.el --- Grabs the path to JSON values in a JSON file -*- lexical-binding: t -*-
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;; Copyright (C) 2013 Sterling Graham <sterlingrgraham@gmail.com>
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;; Author: Sterling Graham <sterlingrgraham@gmail.com>
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;; URL: http://github.com/sterlingg/json-snatcher
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;; Package-Version: 20150511.2047
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;; Version: 1.0
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;; Package-Requires: ((emacs "24"))
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;; This file is not part of GNU Emacs.
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;;; Commentary:
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;;
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;; Well this was my first excursion into ELisp programmming. It didn't go too badly once
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;; I fiddled around with a bunch of the functions.
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;;
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;; The process of getting the path to a JSON value at point starts with
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;; a call to the jsons-print-path function.
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;;
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;; It works by parsing the current buffer into a list of parse tree nodes
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;; if the buffer hasn't already been parsed in the current Emacs session.
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;; While parsing, the region occupied by the node is recorded into the
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;; jsons-parsed-regions hash table as a list.The list contains the location
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;; of the first character occupied by the node, the location of the last
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;; character occupied, and the path to the node. The parse tree is also stored
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;; in the jsons-parsed list for possible future use.
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;;
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;; Once the buffer has been parsed, the node at point is looked up in the
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;; jsons-curr-region list, which is the list of regions described in the
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;; previous paragraph for the current buffer. If point is not in one of these
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;; interval ranges nil is returned, otherwise the path to the value is returned
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;; in the form [<key-string>] for objects, and [<loc-int>] for arrays.
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;; eg: ['value1'][0]['value2'] gets the array at with name value1, then gets the
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;; 0th element of the array (another object), then gets the value at 'value2'.
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;;
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;;; Installation:
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;;
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;; IMPORTANT: Works ONLY in Emacs 24 due to the use of the lexical-binding variable.
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;;
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;; To install add the json-snatcher.el file to your load-path, and
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;; add the following lines to your .emacs file:
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;;(require 'json-snatcher)
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;; (defun js-mode-bindings ()
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;; "Sets a hotkey for using the json-snatcher plugin."
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;; (when (string-match "\\.json$" (buffer-name))
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;; (local-set-key (kbd "C-c C-g") 'jsons-print-path)))
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;; (add-hook 'js-mode-hook 'js-mode-bindings)
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;; (add-hook 'js2-mode-hook 'js-mode-bindings)
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;;
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;; This binds the key to snatch the path to the JSON value to C-c C-g only
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;; when either JS mode, or JS2 mode is active on a buffer ending with
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;; the .json extension.
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;;; License:
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;; This program is free software; you can redistribute it and/or
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;; modify it under the terms of the GNU General Public License
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;; as published by the Free Software Foundation; either version 3
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;; of the License, or (at your option) any later version.
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;;
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;; This program is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;;
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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;; Boston, MA 02110-1301, USA.
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;;; Code:
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(defvar jsons-curr-token 0
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"The current character in the buffer being parsed.")
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(defvar jsons-parsed (make-hash-table :test 'equal)
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"Hashes each open buffer to the parse tree for that buffer.")
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(defvar jsons-parsed-regions (make-hash-table :test 'equal)
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"Hashes each open buffer to the ranges in the buffer for each of the parse trees nodes.")
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(defvar jsons-curr-region () "The node ranges in the current buffer.")
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(defvar jsons-path-printer 'jsons-print-path-python "Default jsons path printer")
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(add-hook 'kill-buffer-hook 'jsons-remove-buffer)
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(defun jsons-consume-token ()
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"Return the next token in the stream."
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(goto-char jsons-curr-token)
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(let* ((delim_regex "\\([\][\\{\\}:,]\\)")
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;; TODO: Improve this regex. Although now it SEEMS to be working, and can be
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;; used to validate escapes if needed later. The second half of the string regex is pretty
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;; pointless at the moment. I did it this way, so that the code closely mirrors
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;; the RFC.
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(string_regex "\\(\"\\(\\([^\"\\\\\r\s\t\n]\\)*\\([\r\s\t\n]\\)*\\|\\(\\(\\\\\\\\\\)*\\\\\\(\\([^\r\s\t\n]\\|\\(u[0-9A-Fa-f]\\{4\\}\\)\\)\\)\\)\\)+\"\\)")
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(num_regex "\\(-?\\(0\\|\\([1-9][[:digit:]]*\\)\\)\\(\\.[[:digit:]]+\\)?\\([eE][-+]?[[:digit:]]+\\)?\\)")
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(literal_regex "\\(true\\|false\\|null\\)")
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(full_regex (concat "\\(" delim_regex "\\|" literal_regex "\\|" string_regex "\\|" num_regex "\\)")))
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(if (re-search-forward full_regex (point-max) "Not nil")
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(progn
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(setq jsons-curr-token (match-end 0))
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(buffer-substring-no-properties (match-beginning 0) (match-end 0)))
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(message "Reached EOF. Possibly invalid JSON."))))
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(defun jsons-array (path)
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"Create a new json array object that contain the identifier \"json-array\".
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a list of the elements contained in the array, and the PATH to the array."
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(let*(
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(token (jsons-consume-token))
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(array "json-array")
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(elements ())
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(i 0))
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(while (not (string= token "]"))
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(if (not (string= token ","))
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(let ((json-val (jsons-value token path i)))
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(setq i (+ i 1))
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(push json-val elements)
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(setq token (jsons-consume-token)))
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(setq token (jsons-consume-token))))
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(list array (reverse elements) path)))
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(defun jsons-literal (token path)
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"Given a TOKEN and PATH, this function return the PATH to the literal."
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(let ((match_start (match-beginning 0))
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(match_end (match-end 0)))
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(progn
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(setq jsons-curr-region (append (list (list match_start match_end path)) jsons-curr-region))
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(list "json-literal" token path (list match_start match_end)))))
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(defun jsons-member (token path)
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"This function is called when a member in a JSON object needs to be parsed.
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Given the current TOKEN, and the PATH to this member."
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(let* ((member ())
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(value token)
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(range_start (match-beginning 0))
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(range_end (match-end 0))
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)
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(setq member (list "json-member" token))
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(if (not (string= (jsons-consume-token) ":"))
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(error "Encountered token other than : in jsons-member")
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nil)
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(let ((json-val (jsons-value (jsons-consume-token) (cons value path) nil)))
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(setq member (list member (append json-val
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(list range_start range_end))))
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(setq jsons-curr-region (append (list (list range_start range_end (elt json-val 2))) jsons-curr-region))
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member)))
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(defun jsons-number (token path)
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"This function will return a json-number given by the current TOKEN.
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PATH points to the path to this number. A json-number is defined as per
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the num_regex in the `jsons-get-tokens' function."
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(progn
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(setq jsons-curr-region (append (list (list (match-beginning 0) (match-end 0) path)) jsons-curr-region))
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(list "json-number" token path)))
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(defun jsons-object (path)
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"This function is called when a { is encountered while parsing.
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PATH is the path in the tree to this object."
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(let*(
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(token (jsons-consume-token))
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(members (make-hash-table :test 'equal))
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(object (list "json-object" members path)))
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(while (not (string= token "}"))
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(if (not (string= token ","))
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(let ((json-mem (jsons-member token path)))
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(puthash (elt (elt json-mem 0) 1) (elt json-mem 1) (elt object 1))
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(setq token (jsons-consume-token)))
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(setq token (jsons-consume-token))))
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object))
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(defun jsons-string (token path)
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"This function is called when a string is encountered while parsing.
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The TOKEN is the current token being examined.
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The PATH is the path to this string."
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(let ((match_start (match-beginning 0))
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(match_end (match-end 0)))
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(progn
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(setq jsons-curr-region (append (list (list match_start match_end path)) jsons-curr-region))
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(list "json-string" token path (list match_start match_end)))))
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(defun jsons-value (token path array-index)
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"A value, which is either an object, array, string, number, or literal.
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The is-array variable is nil if inside an array, or the index in
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the array that it occupies.
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TOKEN is the current token being parsed.
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PATH is the path to this value.
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ARRAY-INDEX is non-nil if the value is contained within an array, and
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points to the index of this value in the containing array."
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;;TODO: Refactor the if array-index statement.
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(if array-index
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(if (jsons-is-number token)
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(list "json-value" (jsons-number token (cons array-index path)) (list (match-beginning 0) (match-end 0)))
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(cond
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((string= token "{") (jsons-object (cons array-index path)))
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((string= token "[") (jsons-array (cons array-index path)))
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((string= (substring token 0 1) "\"") (jsons-string token (cons array-index path)))
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(t (jsons-literal token (cons array-index path)))))
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(if (jsons-is-number token)
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(list "json-value" (jsons-number token path) path (list (match-beginning 0) (match-end 0)))
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(cond
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((string= token "{") (jsons-object path))
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((string= token "[") (jsons-array path))
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((string= (substring token 0 1) "\"") (jsons-string token path))
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(t (jsons-literal token path))))))
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(defun jsons-get-path ()
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"Function to check whether we can grab the json path from the cursor position in the json file."
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(let ((i 0)
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(node nil))
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(setq jsons-curr-region (gethash (current-buffer) jsons-parsed-regions))
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(when (not (gethash (current-buffer) jsons-parsed))
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(jsons-parse))
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(while (< i (length jsons-curr-region))
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(let*
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((json_region (elt jsons-curr-region i))
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(min_token (elt json_region 0))
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(max_token (elt json_region 1)))
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(when (and (> (point) min_token) (< (point) max_token))
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(setq node (elt json_region 2))))
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(setq i (+ i 1)))
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node))
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(defun jsons-is-number (str)
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"Test to see whether STR is a valid JSON number."
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(progn
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(match-end 0)
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(save-match-data
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(if (string-match "^\\(-?\\(0\\|\\([1-9][[:digit:]]*\\)\\)\\(\\.[[:digit:]]+\\)?\\([eE][-+]?[[:digit:]]+\\)?\\)$" str)
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(progn
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(match-end 0)
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t)
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nil))))
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(defun jsons-parse ()
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"Parse the file given in file, return a list of nodes representing the file."
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(save-excursion
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(setq jsons-curr-token 0)
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(setq jsons-curr-region ())
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(if (not (gethash (current-buffer) jsons-parsed))
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(let* ((token (jsons-consume-token))
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(return_val nil))
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(cond
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((string= token "{") (setq return_val (jsons-object ())))
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((string= token "[") (setq return_val (jsons-array ())))
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(t nil))
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(puthash (current-buffer) return_val jsons-parsed)
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(puthash (current-buffer) jsons-curr-region jsons-parsed-regions)
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return_val)
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(gethash (current-buffer) jsons-parsed))))
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(defun jsons-print-to-buffer (node buffer)
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"Prints the given NODE to the BUFFER specified in buffer argument.
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TODO: Remove extra comma printed after lists of object members, and lists of array members."
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(let ((id (elt node 0)))
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(cond
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((string= id "json-array")
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(progn
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(jsons-put-string buffer "[")
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(mapc (lambda (x) (progn
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(jsons-print-to-buffer buffer x)
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(jsons-put-string buffer ",") )) (elt node 1))
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(jsons-put-string buffer "]")))
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((string= id "json-literal")
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(jsons-put-string buffer (elt node 1)))
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((string= id "json-member")
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(jsons-put-string buffer (elt node 1))
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(jsons-put-string buffer ": ")
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(jsons-print-to-buffer buffer (elt node 2)))
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((string= id "json-number")
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(jsons-put-string buffer (elt node 1)))
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((string= id "json-object")
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(progn
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(jsons-put-string buffer "{")
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(maphash (lambda (key value)
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(progn
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(jsons-put-string buffer key)
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(jsons-put-string buffer ":")
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(jsons-print-to-buffer buffer value)
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(jsons-put-string buffer ","))) (elt node 1))
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(jsons-put-string buffer "}")))
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((string= id "json-string")
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(jsons-put-string buffer (elt node 1)))
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((string= id "json-value")
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(jsons-print-to-buffer buffer (elt node 1)))
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(t nil))))
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(defun jsons-print-path-jq ()
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"Print the jq path to the JSON value under point, and save it in the kill ring."
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(let* ((path (jsons-get-path))
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(i 0)
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(jq_str ".")
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key)
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(setq path (reverse path))
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(while (< i (length path))
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(if (numberp (elt path i))
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(progn
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(setq jq_str (concat jq_str "[" (number-to-string (elt path i)) "]"))
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(setq i (+ i 1)))
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(progn
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(setq key (elt path i))
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(setq jq_str (concat jq_str (substring key 1 (- (length key) 1))))
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(setq i (+ i 1))))
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(when (elt path i)
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(unless (numberp (elt path i))
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(setq jq_str (concat jq_str ".")))))
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(progn (kill-new jq_str)
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(princ jq_str))))
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(defun jsons-print-path-python ()
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"Print the python path to the JSON value under point, and save it in the kill ring."
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(let ((path (jsons-get-path))
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(i 0)
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(python_str ""))
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(setq path (reverse path))
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(while (< i (length path))
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(if (numberp (elt path i))
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(progn
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(setq python_str (concat python_str "[" (number-to-string (elt path i)) "]"))
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(setq i (+ i 1)))
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(progn
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(setq python_str (concat python_str "[" (elt path i) "]"))
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(setq i (+ i 1)))))
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(progn (kill-new python_str)
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(princ python_str))))
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;;;###autoload
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(defun jsons-print-path ()
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"Print the path to the JSON value under point, and save it in the kill ring."
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(interactive)
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(funcall jsons-path-printer))
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(defun jsons-put-string (buffer str)
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"Append STR to the BUFFER specified in the argument."
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(save-current-buffer
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(set-buffer (get-buffer-create buffer))
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(insert (prin1-to-string str t))))
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(defun jsons-remove-buffer ()
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"Used to clean up the token regions, and parse tree used by the parser."
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(progn
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(remhash (current-buffer) jsons-parsed)
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(remhash (current-buffer) jsons-parsed-regions)))
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(provide 'json-snatcher)
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;; Local-Variables:
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;; indent-tabs-mode: nil
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;; End:
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;;; json-snatcher.el ends here
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