-# 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 JavaScript 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 were declared.
-- Identifiers are bold when first declared.
-- Comments are gray and italic.
+By default, comments and strings are still highlighted syntactically.
-In JavaScript, we are constantly leveraging closures to bind nearby
-data. Lexical scope information at-a-glance can assist a programmer in
-understanding the overall structure of a program. It can also help curb nasty
-bugs like implicit globals and name shadowing, and act as an indicator of
-excessive complexity.
+## Features
-There are some breakthrough advantages, too. Context coloring could enable a
-programmer to write in a functional style. It would be easy to tell when he had
-escaped the boundaries of his function and produced side-effects.
+- Light and dark customizable color schemes.
+- JavaScript support:
+ - Script, function and block scopes (and even `catch` block scopes).
+ - Node.js "file-level" scope detection.
+- Emacs Lisp support:
+ - `defun`, `lambda`, `let`, `let*`, `cond`, `condition-case`, `defadvice`,
+ `dolist`, `quote`, `backquote` and backquote splicing.
+ - Works in `eval-expression` too.
-Context coloring also improves a programmer's ability to write functions that
-construct objects with implicit private state (which is a good way to avoid
-`this` too).
+## Installation
-This coloring scheme is probably more useful than conventional JavaScript
-*syntax* highlighting. Highlighting keywords can help detect spelling errors, or
-alert one to unclosed string literals; but so can a [linter][]. (If you haven't
-already, you should [integrate][emacs integration] one into your editor.)
+Requires Emacs 24.3+. JavaScript language support requires
+[js2-mode](https://github.com/mooz/js2-mode).
-## Usage
+To install, run the command `M-x package-install RET context-coloring RET`, and
+then add the following to your init file:
-Requires Emacs 24+ and [Node.js 0.10+][node].
+```lisp
+;; JavaScript:
+(add-to-list 'auto-mode-alist '("\\.js\\'" . js2-mode))
+(add-hook 'js2-mode-hook #'context-coloring-mode)
-- Clone this repository.
-- Run `make` in it.
-- Add it to your [load path][].
-- Add the following to your `~/.emacs`:
+;; Emacs Lisp:
+(add-hook 'emacs-lisp-mode-hook #'context-coloring-mode)
-```lisp
-(require 'context-coloring)
-(add-hook 'js-mode-hook 'context-coloring-mode)
+;; eval-expression:
+(add-hook 'eval-expression-minibuffer-setup-hook #'context-coloring-mode) ; 24.4+
+(add-hook 'minibuffer-setup-hook #'context-coloring-mode) ; 24.3
```
-[linter]: https://github.com/jacksonrayhamilton/jslinted
-[emacs integration]: https://github.com/jacksonrayhamilton/jslinted#emacs-integration
-[node]: http://nodejs.org/download/
-[load path]: https://www.gnu.org/software/emacs/manual/html_node/emacs/Lisp-Libraries.html
+## Color Schemes
+
+The [Zenburn](https://github.com/bbatsov/zenburn-emacs) theme, featured in the
+screenshot above, now supports context coloring.
+
+You can define your own colors by customizing faces like
+`context-coloring-level-N-face`, where N is a number starting from 0.
+
+[See here](https://gist.github.com/jacksonrayhamilton/6b89ca3b85182c490816) for
+some color schemes for popular custom themes.
+
+## Options
+
+- `context-coloring-syntactic-comments` (default: `t`): If non-nil, also color
+ comments using `font-lock`.
+- `context-coloring-syntactic-strings` (default: `t`): If non-nil, also color
+ strings using `font-lock`.
+- `context-coloring-javascript-block-scopes` (default: `nil`): If non-nil, also
+ color block scopes in the scope hierarchy in JavaScript.
+- `context-coloring-javascript-detect-top-level-scope` (default: `t`): If
+ non-nil, detect when to use file-level scope.