guile/ice-9/and-let-star.scm

;;;; and-let-star.scm --- and-let* syntactic form (draft SRFI-2) for Guile
;;;; written by Michael Livshin <mike@olan.com>
;;;;
;;;; 	Copyright (C) 1999, 2001, 2002 Free Software Foundation, Inc.
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(define-module (ice-9 and-let-star))

(defmacro and-let* (vars . body)

  (define (expand vars body)
    (cond
     ((null? vars)
      `(begin ,@body))
     ((pair? vars)
      (let ((exp (car vars)))
        (cond
         ((pair? exp)
          (cond
           ((null? (cdr exp))
            `(and ,(car exp) ,(expand (cdr vars) body)))
           (else
            (let ((var (car exp))
                  (val (cadr exp)))
              `(let (,exp)
                 (and ,var ,(expand (cdr vars) body)))))))
         (else
          `(and ,exp ,(expand (cdr vars) body))))))
     (else
      (error "not a proper list" vars))))

  (expand vars body))

(export and-let*)

;;; and-let-star.scm ends here