Scheme - Starting with the basics - Fruitful subroutines(Ackermann function) - Think Scheme

Think Perl 6

開発環境

• macOS Sierra - Apple (OS)
• Emacs (Text Editor)
• Scheme (プログラミング言語)
• kscm(コンパイラ(ksc)・インタプリタ(ksi)、実装)
• 計算機プログラムの構造と解釈(参考書籍)

Think Perl 6: How to Think Like a Computer Scientist (Laurent Rosenfeld(著)、Allen B. Downey(著)、Oreilly & Associates Inc)のPart 1(Starting with the basics)、Chapter 5(Fruitful subroutines)の Exercise 5-2.を Scheme で取り組んでみる。

Exercise 5-2.

コード(Emacs)

(begin
  (load "./lib/stdlib/base.scm")
  (define (ack m n)
    (cond ((= m 0) (+ n 1))
          ((and (> m 0) (= n 0)) (ack (- m 1) 1))
          (#t (ack (- m 1) (ack m (- n 1))))))
  (define result (ack 3 4))
  (display result)
  (newline)
  (= result 125)
  )

入出力結果(Terminal, REPL)

$ ./ksc temp && ./temp
=> compiled
125
=> #true
$