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;;;; and-let-star.scm --- and-let* syntactic form (draft SRFI-2) for Guile
;;;; written by Michael Livshin <mike@olan.com>
;;;;
;;;; Copyright (C) 1999 Free Software Foundation, Inc.
;;;;
;;;; This program is free software; you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; the Free Software Foundation; either version 2, or (at your option)
;;;; any later version.
;;;;
;;;; This program is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;;; GNU General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU General Public License
;;;; along with this software; see the file COPYING. If not, write to
;;;; the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
;;;; Boston, MA 02111-1307 USA
(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-syntax and-let*)
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