The BBEdit text editor for developers has a plug-in mechanism to teach it to do syntax coloring, code folding and such for languages it doesn't already know about. These plug-ins can be installed in the folder ~/Library/Application Support/BBEdit/Language Modules, where the tilde stands for your home folder.

My VRML+3DMF plug-in provides syntax coloring and code folding for the ASCII formats of two 3D object file formats, VRML and 3DMF.

My Ogre Script Language Module helps edit compositor, workspace, and particle system scripts used for the Ogre and Ogre-Next 3D rendering software.