Doing 'emerge cl-ltk' and then trying to use Ltk doesn't work if 'tk' isn't installed. More specifically, after installation, running the code below in CMUCL produces the error: 'No such program: "wish"'. I suggest that 'tk' is added as a dependency of 'cl-ltk'. (require :ltk) (use-package :ltk) (with-ltk (let ((b (make-instance 'button :master nil :text "Press Me" :command (lambda () (format t "Hello World!~&"))))) (pack b)))
Fixed in CVS. Thanks for the note.