An Introduction to Programming in Emacs Lips Chapter 07

Chapter 07

• car
  • Contents of the Address part of Register
• cdr
  • Contents of the Decrement part of the Register
    • この語源は，今となっちゃ irrelevant
  • could-erと発音
  • 日本語にすると，クダァか。
• cons
  • construct
  • 「コンス」?「コンズ」?
  • 「コンスとラクト」だから，「コンス」と発音すると推測。
• 関連する関数
  • length
    • (length '()) => 0
  • nthcdr
    • (nthcdr 2 'list)
      • (cdr (cdr 'list))
    • (nthcdr 100 '()) => nil
  • nth
    • (car (nthcdr 'list))
  • setcar
    • destructive
  • setcdr
    • destructive

Exercise

;;; Exercise 7.7
(cons 'owl (cons 'crow (cons 'sparrow (cons 'swallow ()))))
;; => (owl crow sparrow swallow)
(let ((birds '(owl crow sparrow swallow)))
  (cons birds birds))
;; => ((owl crow sparrow swallow) owl crow sparrow swallow)
(let ((birds '(owl crow sparrow swallow)))
  (setcar birds 'carp)
  birds)
;; => (carp crow sparrow swallow)
(let ((birds '(owl crow sparrow swallow)))
  (setcar birds 'carp)
  (setcdr birds '(salmon tuna sardine))
  birds)
;; => (carp salmon tuna sardine)