Example: SET-TO-ONE

Takes any number of arguments, which must be symbols, and gives each the value 1.

(defmacro set-to-one (&rest symbols)

(append '(progn)

(mapcar #'(lambda (s) (list 'setq s 1))

symbols)))

> (macroexpand '(set-to-one x y z))

(PROGN (SETQ X 1) (SETQ Y 1) (SETQ Z 1))

T

> (set-to-one x y z)

1

> y

1

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