Implement INTERVAL-PROPERTIES-EQUAL?.

diff --git a/v7/src/edwin/txtprp.scm b/v7/src/edwin/txtprp.scm
index 0d0bb177fecf71609ba353e138de9547411a463f..707878cc978885f0399745f928da23d7094b0785 100644 (file)
--- a/v7/src/edwin/txtprp.scm
+++ b/v7/src/edwin/txtprp.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;    $Id: txtprp.scm,v 1.2 1993/08/10 06:35:54 cph Exp $
+;;;    $Id: txtprp.scm,v 1.3 1993/08/10 09:44:18 cph Exp $
 ;;;
 ;;;    Copyright (c) 1993 Massachusetts Institute of Technology
 ;;;
@@ -178,6 +178,17 @@
                  (if (equal? p (assq prop (interval-properties prev)))
                      (loop (previous-interval prev))
                      (interval-start prev))))))))
+
+(define (interval-properties-equal? p1 p2)
+  ;; Slow but effective.
+  (let ((subset?
+        (lambda (p1 p2)
+          (let loop ((p1 p1))
+            (or (null? p1)
+                (and (assq (caar p1) p2)
+                     (loop (cdr p1))))))))
+    (and (subset? p1 p2)
+        (subset? p2 p1))))
 \f
 ;;; The READ-ONLY property is applied to a contiguous region of
 ;;; characters.  No insertions are allowed within that region, and no