Syntax Coloring of Source Code

Trac supports language-specific syntax highlighting of source code in wiki formatted text and the repository browser.

To do this, Trac uses external libraries with support for a great number of programming languages.

Currently Trac supports syntax coloring using one or more of the following packages:

• ​GNU Enscript
• ​SilverCity
• ​Pygments (but needs a plugin for 0.10, see below)

To activate syntax coloring, simply install either one (or more) of these packages. No additional configuration is required, however to modify the colors, have a look at trac/htdocs/css/code.css.

If you don't know why trac isnt detecting an installed library, try turning on Trac logging. It actually appears that Trac is broken with SilverCity 0.9.6. Either use the current 0.9.7 or the older 0.9.5 ​http://trac.edgewall.org/wiki/TracFaq#why-is-my-css-code-not-being-highlighted-even-though-i-have-silvercity-installed

When in use, Trac will automatically prioritize SilverCity highlighting over Enscript if possible, (see note below).

If neither package is available, Trac will display the data as plain text.

Note: Enscript supports a greater number of languages, however SilverCity is generally faster since it is a library and isn't executed in an external process.

About SilverCity

SilverCity uses the lexer from ​Scintilla. Scintilla supports more languages than SilverCity implements. If you want to add a language to SilverCity supported by Scintilla, it's not very difficult. See ​SilverCityAddLanguage for some information how.

About Pygments

Starting with trac 0.11 ​pygments will be the new default highlighter. It's a highlighting library implemented in pure python, very fast, easy to extend and ​well documented. While it does not support as many languages as Enscript or Scintilla the overall output quality is much better.

To use pygments in trac 0.11 you just have to install pygments 0.6 or higher. If you want to use it in trac 0.10 too you have to install the ​TracPygmentsPlugin from trac hacks. If you encounter any bugs, please file tickets regarding Pygments in ​the pygments trac.

It's very likely that the list below is outdated because the list of supported pygments lexers is growing weekly. Just have a look at the page of ​supported lexers on the pygments webpage.

Syntax Coloring Support

	SilverCity	Enscript	Pygments
Ada		X
Asm		X
Apache Conf (htaccess))			X
* ASP	X	X
* C	X	X	X
* C#		X(2)	X
* C++	X	X	X
* Java	X(4)	X	X
Awk		X
Boo			X
CSS	X		X
Python Doctests			X
Diff		X	X
Eiffel		X
Elisp		X
Fortran		X(3)
Haskell		X	X
Genshi			X
HTML	X	X	X
IDL		X
INI			X
Javascript	X	X	X
Lua			X
m4		X
Makefile		X	X
Mako			X
Matlab		X (5)
Mygthy			X
Objective-C		X
OCaml			X
Pascal		X	X
* Perl	X	X	X
* PHP	X		X
PSP	X
Pyrex		X
* Python	X	X	X
* Ruby	X	X (1)	X
Scheme		X	X
Shell		X	X
Smarty			X
SQL	X	X	X
Troff		X	X
TCL		X
Tex		X	X
Verilog	X(4)	X
VHDL		X
Visual Basic	X		X
VRML		X
XML	X		X

(*) Supported as inline code blocks in Wiki text using WikiProcessors.

(1) Ruby highlighting is not included in the Enscript distribution. Highlighting rules for Ruby can be obtained from: ​http://neugierig.org/software/ruby/

(2) C# highlighting is not included in the Enscript distribution. Highlighting rules for C# can be obtained from: ​http://wiki.hasno.info/index.php/Csharp.st

(3) Fortran: as packaged, Enscript only supports the fixed source form. Highlighting rules for Fortran 90x/2003 can be obtained from: ​http://wiki.hasno.info/index.php/F90.st

(4) since Silvercity 0.9.7 released on 2006-11-23

(5) By default .m files are considered Objective-C files. In order to treat .m files as MATLAB files, add "text/x-matlab:m" to the "mime_map" setting in the [mimeviewer] section of trac.ini.

Extra Software

• GNU Enscript -- ​http://directory.fsf.org/GNU/enscript.html
• GNU Enscript for Windows -- ​http://gnuwin32.sourceforge.net/packages/enscript.htm
• SilverCity -- ​http://silvercity.sf.net/
• Pygments -- ​http://pygments.org/

---

See also: WikiProcessors, WikiFormatting, TracWiki, TracBrowser