New syntax highlighting script

Published 11 March, 2007 in Programming - 0 Comments
This script is part of PLib

A couple of years ago I wrote a generic syntax highlighting script. What I did was using the syntax files from Edit+ to determine how to parse a given language. All languages have different keywords, function names, delimiters and so on, and to know how to highlight a certain language you need to know these things. The Edit+ .stx files describes all these things.

Since I have gotten a few years more of knowledge, and PHP5 has arrived, I though I should write a new version of it. I could reuse some of the code but alot was rewritten and redesigned totally. The script has two classes:

  1. One class to parse the Edit+ syntax files which gets converted into PHP files so that the syntax files doesn’t have to to be parsed for every request. If the given .stx file has a newer timestamp than the cached PHP file the PHP file will be regenerated. Alot of this code could be reused from the older version
  2. The actual highlighting class. This class was almost entirely rewritten. Here I loop through every character of the code to highlight. When a keyword, delimiter or something else detectable is matched I grab that and searches forward to where the rule ends. In the older version I had a different approach where the code was splitted on newlines so I looped through line by line and for each line I looped throuh each charachter and did a similar match as in the new version.

    The new approach has some advantages:

    1. There’s no need to duplicate the code wich means a lot less memory is used.
    2. Fewer flags is needed since when I match a detectable rule I at once search for the end of the rule. This means that fewer .stx statements is needed wich speeds thing up alot.

      And foremost the code got much much cleaner!

Anyhow! There are a few minor bugs but the code is pretty usable (I have implemented it here in the blogging system). I added the scripts with documentation and a simple example on the server for anyone to download.

The Syntaxer2 can be found and downloaded over here. Some bug fixes and more examples will be done in the very near future.