Quack

Quack is a package that enhance Emacs support for Scheme. It supports many different interpreters such as Guile, Racket, etc. Geiser uses its own Quack version and, thus, makes Quack alone a good light alternative.

When you have installed it, you can add these lines to your .emacs file:

;; The binary of your interpreter
(setq scheme-program-name "racket")

;; This hook lets you use your theme colours instead of quack's ones.
(defun scheme-mode-quack-hook ()
  (require 'quack)
  (setq quack-fontify-style 'emacs))
(add-hook 'scheme-mode-hook 'scheme-mode-quack-hook)