Glimmer is currently the most advanced text/code editor for GNOME. It is a full
featured code editor with many advanced features, including scripting
integration with either Python or Guile.

At the current time, Glimmer has syntax highlighting support for the following
languages: Bash/Sh, C/C++, HTML, Java, Latex, GNU  Make, Perl, PHP, PO
(Language Translation), Python, Scheme (guile, lisp, etc), SGML, WML, XML, and
Z80 Assembly.

WWW: http://glimmer.sourceforge.net/