mapc

mapというよりforEachで副作用を起こすのに使う。戻り値は渡したシーケンス自体になる。

code: fns.c

DEFUN ("mapc", Fmapc, Smapc, 2, 2, 0,

doc: /* Apply FUNCTION to each element of SEQUENCE for side effects only.

Unlike `mapcar', don't accumulate the results. Return SEQUENCE.

SEQUENCE may be a list, a vector, a bool-vector, or a string. */)

(Lisp_Object function, Lisp_Object sequence)

{

register EMACS_INT leni;

leni = XFIXNAT (Flength (sequence));

if (CHAR_TABLE_P (sequence))

wrong_type_argument (Qlistp, sequence);

mapcar1 (leni, 0, function, sequence);

return sequence;

}

code: example.el

(mapc (lambda (x) (message "value: %c" x)) "123")

;; => > value: 1

;; => > value: 2

;; => > value: 3

;; => "123"

(mapc (lambda (x) (message "value: %s" x)) '(1 2 3))

;; => > value: 1

;; => > value: 2

;; => > value: 3

;; => (1 2 3)