Example: SET-TO-ONE

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

> (define-macro (set-to-one . symbols)

(append '(begin)

(map (lambda (s) (list 'set! s 1))

symbols)))

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

(BEGIN (SET! X 1) (SET! Y 1) (SET! Z 1))

> (define x 0)

> (define y 0)

> (define z 0)

> (set-to-one x y z)

> y

1

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