From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 4 Jun 1997 22:44:21 +0000 (+0000)
Subject: Reimplement INSTANCE-PREDICATE to return a generic procedure.  Move
X-Git-Tag: 20090517-FFI~5158
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=86bca959d1cf4712780d9594e1606af28c1f480d;p=mit-scheme.git

Reimplement INSTANCE-PREDICATE to return a generic procedure.  Move
INSTANCE-PREDICATE and INSTANCE-OF? to "instance.scm".
---

diff --git a/v7/src/sos/instance.scm b/v7/src/sos/instance.scm
index 976c78a6c..41fbc1f47 100644
--- a/v7/src/sos/instance.scm
+++ b/v7/src/sos/instance.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;; $Id: instance.scm,v 1.2 1997/06/04 22:28:54 cph Exp $
+;;; $Id: instance.scm,v 1.3 1997/06/04 22:44:21 cph Exp $
 ;;;
 ;;; Copyright (c) 1995-97 Massachusetts Institute of Technology
 ;;;
@@ -158,7 +158,8 @@
   (dispatch-tag-contents (tagged-vector-tag instance)))
 
 (define (instance-predicate class)
-  (guarantee-class class 'INSTANCE-PREDICATE)
+  (if (not (class? class))
+      (error:wrong-type-argument class "class" 'INSTANCE-PREDICATE))
   (let ((predicate (make-generic-procedure 1)))
     (let ((add
 	   (lambda (c v)