+** Scheme
+Install =guile=, =guile= is an implementation of =Scheme= programming language.
+#+BEGIN_SRC sh
+ brew install guile
+#+END_SRC
+
+#+BEGIN_SRC emacs-lisp :tangle yes :results silent
+ (setq geiser-scheme-implementation 'guile)
+#+END_SRC
+
+#+BEGIN_SRC scheme
+ (define a "3")
+ a
+#+END_SRC
+
+#+RESULTS:
+: 3
+
+** Racket
+#+BEGIN_SRC emacs-lisp :tangle yes :results silent
+ (use-package racket-mode
+ :ensure t
+ :config
+ (define-key racket-mode-map (kbd "s-r") 'racket-run)
+ (add-to-list 'racket-mode-hook (lambda () (lispy-mode 1))))
+
+ ;; set racket path
+ (setenv "PATH" (concat (getenv "PATH")
+ ":" "/Applications/Racket v6.6/bin"))
+ (setenv "MANPATH" (concat (getenv "MANPATH")
+ ":" "/Applications/Racket v6.6/man"))
+ (setq exec-path (append exec-path '("/Applications/Racket v6.6/bin")))
+
+ (add-to-list 'auto-mode-alist '("\\.rkt\\'" . racket-mode))
+#+END_SRC
+