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nkanaev/notation.lsp

Created February 10, 2019 16:46
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notation.lsp
(defmacro rpn (&rest tokens)
(let ((st (list)))
(dolist (x tokens (pop st))
(if (symbolp x)
(let* ((op2 (pop st))
(op1 (pop st)))
(push (list x op1 op2) st))
(push x st)))))
(assert (equal 3 (rpn 1 2 +)))
(assert (equal 2 (rpn 1 2 *)))
(assert (equal 1 (rpn 1 2 - 5 * 6 +)))
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