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+;;; srfi-9.scm --- define-record-type
+
+;; Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc.
+;;
+;; This library is free software; you can redistribute it and/or
+;; modify it under the terms of the GNU Lesser General Public
+;; License as published by the Free Software Foundation; either
+;; version 2.1 of the License, or (at your option) any later version.
+;;
+;; This library 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
+;; Lesser General Public License for more details.
+;;
+;; You should have received a copy of the GNU Lesser General Public
+;; License along with this library; if not, write to the Free Software
+;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+;;; Commentary:
+
+;; This module exports the syntactic form `define-record-type', which
+;; is the means for creating record types defined in SRFI-9.
+;;
+;; The syntax of a record type definition is:
+;;
+;; <record type definition>
+;; -> (define-record-type <type name>
+;; (<constructor name> <field tag> ...)
+;; <predicate name>
+;; <field spec> ...)
+;;
+;; <field spec> -> (<field tag> <accessor name>)
+;; -> (<field tag> <accessor name> <modifier name>)
+;;
+;; <field tag> -> <identifier>
+;; <... name> -> <identifier>
+;;
+;; Usage example:
+;;
+;; guile> (use-modules (srfi srfi-9))
+;; guile> (define-record-type :foo (make-foo x) foo?
+;; (x get-x) (y get-y set-y!))
+;; guile> (define f (make-foo 1))
+;; guile> f
+;; #<:foo x: 1 y: #f>
+;; guile> (get-x f)
+;; 1
+;; guile> (set-y! f 2)
+;; 2
+;; guile> (get-y f)
+;; 2
+;; guile> f
+;; #<:foo x: 1 y: 2>
+;; guile> (foo? f)
+;; #t
+;; guile> (foo? 1)
+;; #f
+
+;;; Code:
+
+(define-module (srfi srfi-9)
+ :export-syntax (define-record-type))
+
+(cond-expand-provide (current-module) '(srfi-9))
+
+(define-macro (define-record-type type-name constructor/field-tag
+ predicate-name . field-specs)
+ `(begin
+ (define ,type-name
+ (make-record-type ',type-name ',(map car field-specs)))
+ (define ,(car constructor/field-tag)
+ (record-constructor ,type-name ',(cdr constructor/field-tag)))
+ (define ,predicate-name
+ (record-predicate ,type-name))
+ ,@(map
+ (lambda (spec)
+ (cond
+ ((= (length spec) 2)
+ `(define ,(cadr spec)
+ (record-accessor ,type-name ',(car spec))))
+ ((= (length spec) 3)
+ `(begin
+ (define ,(cadr spec)
+ (record-accessor ,type-name ',(car spec)))
+ (define ,(caddr spec)
+ (record-modifier ,type-name ',(car spec)))))
+ (else
+ (error "invalid field spec " spec))))
+ field-specs)))
+
+;;; srfi-9.scm ends here