Thrift.tmbundle is a project mainly written in ..., it's free.
Thrift textmate bundle with union support
This is a clone of the svn repository of the official Thrift.tmbundle See: http://svn.textmate.org/trunk/Bundles/Thrift.tmbundle/
I added support for unions (both highlighting and snippets). Enjoy.
mkdir -p ~/Library/Application Support/TextMate/Bundles
cd ~/Library/Application Support/TextMate/Bundles
git clone git://github.com/bakkdoor/Thrift.tmbundle.git
osascript -e 'tell app "TextMate" to reload bundles'