1 # Context Coloring [![Build Status](https://travis-ci.org/jacksonrayhamilton/context-coloring.png?branch=master)](https://travis-ci.org/jacksonrayhamilton/context-coloring) [![Coverage Status](https://coveralls.io/repos/jacksonrayhamilton/context-coloring/badge.svg?branch=master)](https://coveralls.io/r/jacksonrayhamilton/context-coloring?branch=master)
4 <img alt="Screenshot of JavaScript code highlighted by context." src="screenshot.png" title="Screenshot">
7 Highlights code by scope. Top-level scopes are one color, second-level scopes
8 are another color, and so on. Variables retain the color of the scope in which
9 they are defined. A variable defined in an outer scope referenced by an inner
10 scope is colored the same as the outer scope.
12 By default, comments and strings are still highlighted syntactically.
16 - Light and dark (customizable) color schemes.
18 - Script, function and block scopes (and even `catch` block scopes).
19 - Very fast for files under 1000 lines.
21 - `defun`, `lambda`, `let`, `let*`, quotes, backticks, commas.
22 - 25,000 lines per second!
28 JavaScript language support requires either [js2-mode][], or
29 [Node.js 0.10+][node] and the [scopifier][] executable.
33 - `M-x package-install RET context-coloring RET`
37 - Clone this repository.
41 git clone https://github.com/jacksonrayhamilton/context-coloring.git
44 - Byte-compile the package for improved speed.
51 - Add the following to your init file:
54 (add-to-list 'load-path "~/.emacs.d/context-coloring")
55 (require 'context-coloring)
58 ### Dependencies (js-mode)
61 npm install -g scopifier
66 Add the following to your init file:
70 (add-hook 'js-mode-hook 'context-coloring-mode)
73 (add-to-list 'auto-mode-alist '("\\.js\\'" . js2-mode))
74 (add-hook 'js2-mode-hook 'context-coloring-mode)
77 (add-hook 'emacs-lisp-mode-hook 'context-coloring-mode)
84 - `context-coloring-syntactic-comments` (default: `t`): If non-nil, also color
85 comments using `font-lock`.
86 - `context-coloring-syntactic-strings` (default: `t`): If non-nil, also color
87 strings using `font-lock`.
88 - `context-coloring-delay` (default: `0.25`; supported modes: `js-mode`,
89 `js3-mode`, `emacs-lisp-mode`): Delay between a buffer update and
91 - `context-coloring-js-block-scopes` (default: `nil`; supported modes:
92 `js2-mode`): If non-nil, also color block scopes in the scope hierarchy in
97 Color schemes for custom themes are automatically applied when those themes are
98 active. Built-in theme support is available for: `ample`, `anti-zenburn`,
99 `grandshell`, `leuven`, `monokai`, `solarized`, `spacegray`, `tango` and
102 You can define your own theme colors too:
105 (context-coloring-define-theme
120 See `C-h f context-coloring-define-theme` for more info on theme parameters.
124 To add support for a new language, write a "scopifier" for it, and define a new
125 coloring dispatch strategy with `context-coloring-define-dispatch`. Then the
126 plugin should handle the rest. (See `C-h f context-coloring-define-dispatch`
127 for more info on dispatch strategies.)
129 A "scopifier" is a CLI program that reads a buffer's contents from stdin and
130 writes a JSON array of numbers to stdout. Every three numbers in the array
131 represent a range of color. For instance, if I fed the following string of
132 JavaScript code to a scopifier
135 var a = function () {};
138 then the scopifier would produce the following array
144 where, for every three numbers, the first number is a 1-indexed start [point][],
145 the second number is an exclusive end point, and the third number is a scope
146 level. The result of applying level 0 coloring to the range [1, 24) and
147 then applying level 1 coloring to the range [9, 23) would result in the
151 <img alt="Screenshot of ranges [1, 24) and [9, 23)." src="scopifier.png" title="Screenshot">
154 If there is an abstract syntax tree generator for your language, you can walk
155 the syntax tree, find variables and scopes, and build their positions and levels
156 into an array like the one above.
158 For example, a Ruby scopifier might be defined and implemented like this:
161 (context-coloring-define-dispatch
165 :command "/home/username/scopifier")
174 print scopifier ARGF.read
177 When a `--version` argument is passed, a scopifier should print its version
178 number and exit. This allows context-coloring to determine if an update is
181 Alternatively, you could implement a "colorizer" in Emacs Lisp. A colorizer
182 also handles the job of calling `context-coloring-colorize-region` to apply
183 colors to a buffer. A colorizer may have better performance than a scopifier
184 when parsing and coloring can be performed in the same pass.
186 [js2-mode]: https://github.com/mooz/js2-mode
187 [node]: http://nodejs.org/download/
188 [scopifier]: https://github.com/jacksonrayhamilton/scopifier
189 [point]: http://www.gnu.org/software/emacs/manual/html_node/elisp/Point.html