To get (very rudimentary) Nu highlighting in TextWrangler, put these files (except this readme) into "~/Library/Application Support/TextWrangler/Language Modules/".

By the way, don't forget command-B to select an s-expression; and repeated command-Bs incrementally select containing s-expressions.  That's built in to TextWrangler, not part of my work.

Jason Grossman, 2009