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+;; span.el	Datatype of "spans" for Proof General.
+;;
+;; Copyright (C) 1998 LFCS Edinburgh
+;; Author:    Healfdene Goguen
+;; License:   GPL (GNU GENERAL PUBLIC LICENSE)
+;;
+;; $Id$
+
+;;
+;; Spans are our abstraction of extents/overlays.
+;;
+(eval-and-compile
+  (cond ((string-match "XEmacs" emacs-version)  
+	 (require 'span-extent))
+ 	(t 
+	 (require 'span-overlay))))
+
+;;
+;; Generic functions built on low-level concrete ones.
+;; 
+
+(defsubst delete-spans (start end prop)
+  "Delete all spans between START and END with property PROP set."
+  (mapcar-spans 'delete-span start end prop))
+
+(defsubst span-property-safe (span name)
+  "Like span-property, but return nil if SPAN is nil."
+  (and span (span-property span name)))
+  
+(defsubst set-span-start (span value)
+  "Set the start point of SPAN to VALUE."
+  (set-span-endpoints span value (span-end span)))
+
+(defsubst set-span-end (span value)
+  "Set the end point of SPAN to VALUE."
+  (set-span-endpoints span (span-start span) value))
+
+(provide 'span)
+;; span.el ends here.