TextMate (Mac OS X Only)

There is a Groovy plug-in for the popular TextMate editor on Mac OS X here.

XCode (Mac OS X only)

http://www.vengefulcow.com/groovy/

SubEthaEdit 1.x

Brian McCallister has created a plugin for  SubEthaEdit, which is here.  

SubEthaEdit 2.x

A new-format language "mode" for SubEthaEdit 2.x is available here.

Vim

A Vim plugin is available here (written by Jim Ruley).



Vim provides Groovy syntax highlighting out of the box (syntax file created by Alessio Pace). The syntax file is also available here.

TextPad 4

Guillaume Laforge wrote a syntax file for the TextPad text editor which can be downloaded 

here.  This file should be installed in the Samples subdirectory of your TextPad installation.

EditPlus

Michal Szklanowski contributed a Groovy 1.0 syntax file for the EditPlus text editor which can be downloaded here. Groovy 1.5 syntax and auto-completion library can be downloaded from here.

Emacs

Jeremy Rayner has written a groovy-mode for emacs, details of which can be found on the Emacs Plugin page.

Russel Winder has started an alternative to Jeremy's based on CC Mode (Jeremy's was reworking of ruby-mode). Also Stuart Clayman has created a Groovy execution mode. See the Emacs Plugin page for details.

UltraEdit

Find more info on the UltraEdit Plugin page.

PS PAD

Syntax file for Ps PAd is available here by Marc DeXeT.

Enscript

State file for GNU enscript. It needs to be installed alongside the other enscript state files, for example in /usr/share/enscript/hl/ on SUSE linux.

Highlight

Language definition file for Highlight.

Crimson Editor

Syntax files for Crimson Editor are available here (provided by Jim Ruley).

Kate (KDE4)

Syntax file for Kate (KDE4) based on the Java syntax file is available here.

To install the new syntax file for the system, place it in /usr/share/apps/katepart/syntax.

To install for your user, place the file in ~/.kde4/share/apps/katepart/syntax.

Paths are valid for Arch Linux and may have to be tweaked for other distros.