[The Little Schemer]car

「The Little Schemer」P.5 ～

 

• The Law of Car
  • The primitive car is defined only for non-empty lists.
  • 組み込み手続きcarは空でないlistに対してのみ有効
  • car
    • カー

 

(car '(a b c)) ;; => a

(car '((a b c) x y z)) ;; => (a b c)

(car 'hotdog) ;; => error

(car '()) ;; => error

 

(car '(((hotdogs)) (and) (pickle) relish)) ;; => ((hotdogs))

• 読み ((hotdogs))
  • "The list of the list of hotdogs"
• (car l)
  • list「l」の最初のS式は何？

 

(car (car '(((hotdogs)) (and)))) ;; => (hotdogs)