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5.3 ¥ê¥¹¥È¸þ¤±½Ò¸ì

°Ê²¼¤Î½Ò¸ì¤Ï¡¢Lisp¥ª¥Ö¥¸¥§¥¯¥È¤¬¡¢¥¢¥È¥à¤Ç¤¢¤ë¤«¡¢ ¥³¥ó¥¹¥»¥ë¡¢¤Ä¤Þ¤ê¡¢¥ê¥¹¥È¤Ç¤¢¤ë¤«¡¢ ÆÃÊ̤ʥª¥Ö¥¸¥§¥¯¥Ènil¤Ç¤¢¤ë¤«Ä´¤Ù¤Þ¤¹¡£ ¡Ê¤³¤ì¤é¤Î¿¤¯½Ò¸ì¤Ï¡¢¤½¤ì¤¾¤ì»Ä¤ê¤Î½Ò¸ì¤ÇÄêµÁ²Äǽ¤Ç¤¢¤ë¡£ ¤·¤«¤·¡¢Â¿ÍѤ¹¤ë¤¿¤á¡¢¤³¤ì¤é¤¹¤Ù¤Æ¤òÍѰդ·¤Æ¤ª¤¯²ÁÃͤ¬¤¢¤ë¡£¡Ë

Function: consp object

¤³¤Î´Ø¿ô¤Ï¡¢object¤¬¥³¥ó¥¹¥»¥ë¤Ê¤é¤Ðt¤òÊÖ¤·¡¢ ¤µ¤â¤Ê¤±¤ì¤Ðnil¤òÊÖ¤¹¡£ nil¤Ï¥³¥ó¥¹¥»¥ë¤Ç¤Ï¤Ê¤¤¤¬¡¢¶õ¥ê¥¹¥È¤Ç¤¢¤ë¡£

Function: atom object

¤³¤Î´Ø¿ô¤Ï¡¢object¤¬¥¢¥È¥à¤Ê¤é¤Ðt¤òÊÖ¤·¡¢ ¤µ¤â¤Ê¤±¤ì¤Ðnil¤òÊÖ¤¹¡£ ¥³¥ó¥¹¥»¥ë¤ò½ü¤¯¤¹¤Ù¤Æ¤Î¥ª¥Ö¥¸¥§¥¯¥È¤Ï¥¢¥È¥à¤Ç¤¢¤ë¡£ ¥·¥ó¥Ü¥ënil¤Ï¥¢¥È¥à¤Ç¤â¤¢¤ê¥ê¥¹¥È¤Ç¤â¤¢¤ë¡£ ¤³¤Î¤è¤¦¤ÊLisp¥ª¥Ö¥¸¥§¥¯¥È¤Ïnil¤À¤±¤Ç¤¢¤ë¡£

(atom object) ≡ (not (consp object))
Function: listp object

¤³¤Î´Ø¿ô¤Ï¡¢object¤¬¥³¥ó¥¹¥»¥ë¤«nil¤Ê¤é¤Ðt¤òÊÖ¤¹¡£ ¤µ¤â¤Ê¤±¤ì¤Ðnil¤òÊÖ¤¹¡£

(listp '(1))
     ⇒ t
(listp '())
     ⇒ t
Function: nlistp object

¤³¤Î´Ø¿ô¤Ï¡¢listp¤ÎÈ¿ÂФǤ¢¤ë¡£ object¤¬¥ê¥¹¥È¤Ç¤Ê¤±¤ì¤Ðt¤òÊÖ¤¹¡£ ¤µ¤â¤Ê¤±¤ì¤Ðnil¤òÊÖ¤¹¡£

(listp object) ≡ (not (nlistp object))
Function: null object

¤³¤Î´Ø¿ô¤Ï¡¢object¤¬nil¤Ê¤é¤Ðt¤òÊÖ¤·¡¢ ¤µ¤â¤Ê¤±¤ì¤Ðnil¤òÊÖ¤¹¡£ ¤³¤Î´Ø¿ô¤Ï¡¢not¤ÈƱ°ì¤Ç¤¢¤ë¤¬¡¢°Õ¿Þ¤òÌÀ³Î¤Ë¤¹¤ë¤¿¤á¤Ë¡¢ object¤ò¥ê¥¹¥È¤È¹Í¤¨¤ë¤È¤­¤Ë¤Ïnull¤ò»È¤¤¡¢ object¤ò¿¿ÍýÃͤȹͤ¨¤ë¤È¤­¤Ë¤Ïnot¤ò»È¤¦ ¡ÊCombining Conditions¤Înot¤ò»²¾È¡Ë

(null '(1))
     ⇒ nil
(null '())
     ⇒ t