[The Little Schemer]atom?

「The Little Schemer」P.10 ～

 

(atom? 'Harry) ;; => #t

 

atom?手続き

(define atom?   (lambda (x)     (and (not (pair? x)) (not (null? x)))))

• 対でもなく
• null listでもない

 

(atom? 'Harry) ;; => #t (atom? '(1 2 3)) ;; => #f (atom? '()) ;; => #f

 

(atom? '(Harry had a heap of apples)) ;; => #f

• listだから

 

• atom?手続きはいくつの引数を取りますか？
  • 一つのS式

 

(atom? (car '(Harry  had a heap of apples))) ;; => #t

• (car '(Harry  had a heap of apples))
  • Harry
• (atom? 'Harry)
  • #t