Title: The Wall

Dear Francis,

I was interested in Richard Blundell's comments on code legibility in C Vu 11.6, when he describes the difficulties in speed-reading code with long identifiers and symbols. What is needed is for the symbols to stand out differently, and for this reason (among others) I very much prefer syntax highlighting in the editor.

Syntax highlighting can be done with either fonts or colours, or both. If you have colour vision then you should find that colours work better, so long as they are chosen such that the contrast is good. Font highlighting has the advantage of being more easily printed, although much depends on the choice of fonts.

GNU Emacs can do both, and it calls them both "font-lock" (I find it best on "maximum decoration"). I have not yet found out how to customise the colours that are used for the various parts of the language, but enabling font-lock is simply a matter of putting the following in your .emacs file:

  (setq-default font-lock-auto-fontify t)
  (setq-default font-lock-use-fonts nil)
  (setq-default font-lock-use-colors t)
  (setq-default font-lock-maximum-decoration t)
  (require 'font-lock)

(Of course, xemacs has it all in the menus somewhere.) By the way, that enables syntax highlighting for not only C and C++ but also most of the other languages that emacs knows about, such as SGML/HTML, Lisp, Perl, Prolog, sh, Outline documentation, and numerous others (although the syntax highlighting is better in some than in others).

Another common program that does syntax highlighting is a2ps, a Unix "pretty printer". On Windows, many IDEs are capable of it. Other benefits of syntax highlighting include keyword highlighting (which can reduce problems with miss-spelt keywords), and, when you are used to it, the quick recognition of idioms (such as loops) without having to read them. This is very useful if you need large print, since you can "zoom out" and see more of the code when you are only navigating it.

I urge all readers to try syntax highlighting if you have not already done so, to see if it is for you. Different people will find different results, but it's one of those things that you might as well try. It was not invented just for the visually impaired.

Silas S Brown http://epona.ucam.org/~ssb22

I like that zoom out idea as being something that allows you to see larger scale source code patterns.