Scheme让*作为嵌套的一元让

let*

(define let*→nested-unary-lets
  (match-lambda
   (`(let* (()) ,<exprs>)
   `(let () ,<exprs>))
   (`(let* ((,<var> ,<val>)) ,<exprs>)
   `(let ((,<var> ,<val>)) (let () ,<exprs>)))
   (`(let* ((,<var> ,<val>) ,<clauses>) ,<exprs>)
   `(let ((,<var> ,<val>)) (let*→nested-unary-lets '(let* (,@<clauses>) ,<exprs>))))))

`(let* ((,<var> ,<val>) ,<clauses>) ,<exprs>)

'(let* ((a b) (c d) (e f)) <expressions>)

(c d)

(var val)

((c d) (e f))