89 |
LISTNAME must be a symbol whose value is a list. |
LISTNAME must be a symbol whose value is a list. |
90 |
If the value is nil, `pop' returns nil but does not actually |
If the value is nil, `pop' returns nil but does not actually |
91 |
change the list." |
change the list." |
92 |
(list 'prog1 (list 'car listname) |
(list 'car |
93 |
(list 'setq listname (list 'cdr listname)))) |
(list 'prog1 listname |
94 |
|
(list 'setq listname (list 'cdr listname))))) |
95 |
|
|
96 |
(defmacro when (cond &rest body) |
(defmacro when (cond &rest body) |
97 |
"If COND yields non-nil, do BODY, else return nil." |
"If COND yields non-nil, do BODY, else return nil." |