;;; check-type.lisp
;;;
  Copyright ( C ) 2003 - 2005  
  $ Id$
;;;
;;; 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
  of the License , 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 program; if not, write to the Free Software
  Foundation , Inc. , 59 Temple Place - Suite 330 , Boston , MA   02111 - 1307 , USA .
;;;
;;; As a special exception, the copyright holders of this library give you
;;; permission to link this library with independent modules to produce an
;;; executable, regardless of the license terms of these independent
;;; modules, and to copy and distribute the resulting executable under
;;; terms of your choice, provided that you also meet, for each linked
;;; independent module, the terms and conditions of the license of that
;;; module.  An independent module is a module which is not derived from
;;; or based on this library.  If you modify this library, you may extend
;;; this exception to your version of the library, but you are not
;;; obligated to do so.  If you do not wish to do so, delete this
;;; exception statement from your version.

  Adapted from CMUCL .

(in-package #:system)

(defmacro check-type (place type &optional type-string)
  (let ((place-value (gensym)))
    `(loop
       (let ((,place-value ,place))
         (when (typep ,place-value ',type)
           (return nil))
         (setf ,place
               (check-type-error ',place ,place-value ',type ,type-string))))))

(defun check-type-error (place place-value type type-string)
  (let ((cond (if type-string
                  (make-condition 'simple-type-error
                                  :datum place-value :expected-type type
                                  :format-control
                                  "The value of ~S is ~S, which is not ~A."
                                  :format-arguments
                                  (list place place-value type-string))
		  (make-condition 'simple-type-error
				  :datum place-value :expected-type type
				  :format-control
                                  "The value of ~S is ~S, which is not of type ~S."
				  :format-arguments
				  (list place place-value type)))))
    (restart-case (error cond)
      (store-value (value)
        :report (lambda (stream)
                  (format stream "Supply a new value for ~S."
                          place))
        :interactive read-evaluated-form
        value))))

 check-type.lisp


 This program is free software; you can redistribute it and/or
 either version 2

 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.

 along with this program; if not, write to the Free Software

 As a special exception, the copyright holders of this library give you
 permission to link this library with independent modules to produce an
 executable, regardless of the license terms of these independent
 modules, and to copy and distribute the resulting executable under
 terms of your choice, provided that you also meet, for each linked
 independent module, the terms and conditions of the license of that
 module.  An independent module is a module which is not derived from
 or based on this library.  If you modify this library, you may extend
 this exception to your version of the library, but you are not
 obligated to do so.  If you do not wish to do so, delete this
 exception statement from your version.
  Copyright ( C ) 2003 - 2005  
  $ Id$
  modify it under the terms of the GNU General Public License
  of the License , or ( at your option ) any later version .
  You should have received a copy of the GNU General Public License
  Foundation , Inc. , 59 Temple Place - Suite 330 , Boston , MA   02111 - 1307 , USA .

  Adapted from CMUCL .

(in-package #:system)

(defmacro check-type (place type &optional type-string)
  (let ((place-value (gensym)))
    `(loop
       (let ((,place-value ,place))
         (when (typep ,place-value ',type)
           (return nil))
         (setf ,place
               (check-type-error ',place ,place-value ',type ,type-string))))))

(defun check-type-error (place place-value type type-string)
  (let ((cond (if type-string
                  (make-condition 'simple-type-error
                                  :datum place-value :expected-type type
                                  :format-control
                                  "The value of ~S is ~S, which is not ~A."
                                  :format-arguments
                                  (list place place-value type-string))
		  (make-condition 'simple-type-error
				  :datum place-value :expected-type type
				  :format-control
                                  "The value of ~S is ~S, which is not of type ~S."
				  :format-arguments
				  (list place place-value type)))))
    (restart-case (error cond)
      (store-value (value)
        :report (lambda (stream)
                  (format stream "Supply a new value for ~S."
                          place))
        :interactive read-evaluated-form
        value))))
