;;; Vikalpa --- Prove S-expression
;;; Copyright © 2020 Masaya Tojo <masaya@tojo.tokyo>
;;;
;;; This file is part of Vikalpa.
;;;
;;; Vikalpa 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 3 of the License, or
;;; (at your option) any later version.
;;;
;;; Vikalpa 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 Vikalpa.  If not, see <http://www.gnu.org/licenses/>.

(define-module (vikalpa syntax)
  #:export (define/guard))

(define-syntax-rule (define/guard (name (var pred?) ...) b b* ...)
  (define (name var ...)
    (unless (pred? var)
      (error (format #f
                     "~a:~%  expected:  ~a~%  given: "
                     'name
                     'pred?)
             var))
    ...
    b b* ...))