Is there a way to add syntax highlighting for the Groovy language in kate
?
Or is there a quite similar language, that will work as well?
Yes, you can put this xml file under /usr/share/apps/katepart/syntax/
if you want it to be installed at system's level, otherwise in
~/.kde4/share/apps/katepart/syntax/
if you want it at user's level:
mkdir -p ~/.kde/share/apps/katepart/syntax
cd ~/.kde/share/apps/katepart/syntax
wget http://docs.codehaus.org/download/attachments/2747/groovy.xml
This works for KDE4. For other versions you might follow this blog post.