code.delx.au - gnu-emacs-elpa/blob - README.md

   1 # Context Coloring
   2
   3 <p align="center">
   4   <img alt="Screenshot of JavaScript code highlighted by context." src="screenshot.png" title="Screenshot">
   5 </p>
   6
   7 Highlights JavaScript code according to function context.
   8
   9 - Code in the global scope is one color. Code in functions within the global
  10   scope is a different color, and code within such functions is another color,
  11   and so on.
  12 - Identifiers retain the color of the scope in which they were declared.
  13 - Identifiers are bold when first declared.
  14 - Comments are gray and italic.
  15
  16 In JavaScript, we are constantly leveraging closures to bind nearby
  17 data. Lexical scope information at-a-glance can assist a programmer in
  18 understanding the overall structure of a program. It can also help curb nasty
  19 bugs like implicit globals and name shadowing, and act as an indicator of
  20 excessive complexity.
  21
  22 There are some breakthrough advantages, too. Context coloring could enable a
  23 programmer to write in a functional style. It would be easy to tell when he had
  24 escaped the boundaries of his function and produced side-effects.
  25
  26 Context coloring also improves a programmer's ability to write functions that
  27 construct objects with implicit private state (which is a good way to avoid
  28 `this` too).
  29
  30 This coloring scheme is probably more useful than conventional JavaScript
  31 *syntax* highlighting. Highlighting keywords can help detect spelling errors, or
  32 alert one to unclosed string literals; but so can a [linter][]. (If you haven't
  33 already, you should [integrate][emacs integration] one into your editor.)
  34
  35 ## Usage
  36
  37 Requires Emacs 24+ and [Node.js 0.10+][node].
  38
  39 - Clone this repository.
  40 - Run `make` in it.
  41 - Add it to your [load path][].
  42 - Add the following to your `~/.emacs`:
  43
  44 ```lisp
  45 (require 'context-coloring)
  46 (add-hook 'js-mode-hook 'context-coloring-mode)
  47 ```
  48
  49 [linter]: https://github.com/jacksonrayhamilton/jslinted
  50 [emacs integration]: https://github.com/jacksonrayhamilton/jslinted#emacs-integration
  51 [node]: http://nodejs.org/download/
  52 [load path]: https://www.gnu.org/software/emacs/manual/html_node/emacs/Lisp-Libraries.html