-# Context Coloring [](https://travis-ci.org/jacksonrayhamilton/context-coloring)
+# Context Coloring [](https://travis-ci.org/jacksonrayhamilton/context-coloring) [](https://coveralls.io/r/jacksonrayhamilton/context-coloring?branch=master)
<p align="center">
<img alt="Screenshot of JavaScript code highlighted by context." src="screenshot.png" title="Screenshot">
</p>
-Highlights code according to function context.
+Highlights code by scope. Top-level scopes are one color, second-level scopes
+are another color, and so on. Variables retain the color of the scope in which
+they are defined. A variable defined in an outer scope referenced by an inner
+scope is colored the same as the outer scope.
-- Code in the global scope is one color. Code in functions within the global
- scope is a different color, and code within such functions is another color,
- and so on.
-- Identifiers retain the color of the scope in which they are declared.
-
-Lexical scope information at-a-glance can assist a programmer in understanding
-the overall structure of a program. It can help to curb nasty bugs like name
-shadowing. A rainbow can indicate excessive complexity. State change within a
-closure is easily monitored.
-
-By default, context-coloring still highlights comments and strings
-syntactically. It is still easy to differentiate code from non-code, and strings
-cannot be confused for variables.
-
-This coloring strategy is probably more useful than conventional syntax
-highlighting. Highlighting keywords can help one to detect spelling errors, but
-a [linter][] could also spot those errors, and if integrated with [flycheck][],
-an extra spot opens up in your editing toolbelt.
-
-Give context-coloring a try; you may find that it *changes the way you write
-code*.
+By default, comments and strings are still highlighted syntactically.
## Features
-- Supported languages: JavaScript
- Light and dark (customizable) color schemes.
-- Very fast for files under 1000 lines.
+- JavaScript support:
+ - Script, function and block scopes (and even `catch` block scopes).
+ - Very fast for files under 1000 lines.
+- Emacs Lisp support:
+ - `defun`, `lambda`, `let`, `let*`, `cond`, `condition-case`, `defadvice`,
+ `dolist`, `quote`, `backquote` and backquote splicing.
+ - Instantaneous lazy coloring, 8000 lines-per-second full coloring.
## Installation
make compile
```
-- Add the following to your `~/.emacs` file:
+- Add the following to your init file:
```lisp
(add-to-list 'load-path "~/.emacs.d/context-coloring")
(require 'context-coloring)
```
-### scopifier (for non-js2-mode users)
+### Dependencies (js-mode)
```bash
npm install -g scopifier
## Usage
-Add the following to your `~/.emacs` file:
+Add the following to your init file:
```lisp
-;; non-js2-mode users:
+;; js-mode:
(add-hook 'js-mode-hook 'context-coloring-mode)
-;; js2-mode users:
+;; js2-mode:
(add-to-list 'auto-mode-alist '("\\.js\\'" . js2-mode))
(add-hook 'js2-mode-hook 'context-coloring-mode)
+
+;; emacs-lisp-mode:
+(add-hook 'emacs-lisp-mode-hook 'context-coloring-mode)
```
## Customizing
comments using `font-lock`.
- `context-coloring-syntactic-strings` (default: `t`): If non-nil, also color
strings using `font-lock`.
-- `context-coloring-delay` (default: `0.25`; supported modes: `js-mode`,
- `js3-mode`): Delay between a buffer update and colorization.
+- `context-coloring-default-delay` (default: `0.25`; supported modes: `js-mode`,
+ `js3-mode`): Default (sometimes overridden) delay between a buffer update and
+ colorization.
- `context-coloring-js-block-scopes` (default: `nil`; supported modes:
`js2-mode`): If non-nil, also color block scopes in the scope hierarchy in
JavaScript.
### Color Schemes
Color schemes for custom themes are automatically applied when those themes are
-active. Built-in theme support is available for: `ample`, `anti-zenburn`,
+active. Built-in theme support is available for: `ample`, `anti-zenburn`,
`grandshell`, `leuven`, `monokai`, `solarized`, `spacegray`, `tango` and
`zenburn`.
```lisp
(context-coloring-define-theme
'zenburn
- :colors '("#DCDCCC"
- "#93E0E3"
- "#BFEBBF"
- "#F0DFAF"
- "#DFAF8F"
- "#CC9393"
- "#DC8CC3"
- "#94BFF3"
- "#9FC59F"
- "#D0BF8F"
- "#DCA3A3"))
+ :colors '("#dcdccc"
+ "#93e0e3"
+ "#bfebbf"
+ "#f0dfaf"
+ "#dfaf8f"
+ "#cc9393"
+ "#dc8cc3"
+ "#94bff3"
+ "#9fc59f"
+ "#d0bf8f"
+ "#dca3a3"))
```
See `C-h f context-coloring-define-theme` for more info on theme parameters.
## Extending
To add support for a new language, write a "scopifier" for it, and define a new
-coloring dispatch strategy with `context-coloring-define-dispatch`. Then the
-plugin should handle the rest. (See `C-h f context-coloring-define-dispatch` for
-more info on dispatch strategies.)
+coloring dispatch strategy with `context-coloring-define-dispatch`. Then the
+plugin should handle the rest. (See `C-h f context-coloring-define-dispatch`
+for more info on dispatch strategies.)
A "scopifier" is a CLI program that reads a buffer's contents from stdin and
-writes a JSON array of numbers to stdout. Every three numbers in the array
-represent a range of color. For instance, if I fed the following string of
-JavaScript code to a scopifier:
+writes a JSON array of numbers to stdout. Every three numbers in the array
+represent a range of color. For instance, if I fed the following string of
+JavaScript code to a scopifier
```js
var a = function () {};
```
-Then the scopifier would produce the following array:
+then the scopifier would produce the following array
```js
[1,24,0,9,23,1]
```
-Where, for every three numbers, the first number is a 1-indexed start [point][],
+where, for every three numbers, the first number is a 1-indexed start [point][],
the second number is an exclusive end point, and the third number is a scope
-level. The result of applying level 0 coloring to the range [1, 24) and then
-applying level 1 coloring to the range [9, 23) would result in the following
-coloring:
+level. The result of applying level 0 coloring to the range [1, 24) and
+then applying level 1 coloring to the range [9, 23) would result in the
+following coloring:
<p align="center">
<img alt="Screenshot of ranges [1, 24) and [9, 23)." src="scopifier.png" title="Screenshot">
```
When a `--version` argument is passed, a scopifier should print its version
-number and exit. This allows context-coloring to determine if an update is
+number and exit. This allows context-coloring to determine if an update is
required.
-[linter]: http://jshint.com/about/
-[flycheck]: http://www.flycheck.org/
+Alternatively, you could implement a "colorizer" in Emacs Lisp. A colorizer
+also handles the job of calling `context-coloring-colorize-region` to apply
+colors to a buffer. A colorizer may have better performance than a scopifier
+when parsing and coloring can be performed in the same pass.
+
[js2-mode]: https://github.com/mooz/js2-mode
[node]: http://nodejs.org/download/
[scopifier]: https://github.com/jacksonrayhamilton/scopifier