allow overriding of version view class by controller

browser/concept_macros.pt

@@ -370,7 +370,8 @@
 </metal:actions>
 
 
-<metal:sortable define-macro="sortable_column_header">
+<metal:sortable define-macro="sortable_column_header"
+                tal:define="tableName tableName|nothing">
         <a title="tooltip_sort_column"
            tal:define="colName col/name"
            tal:omit-tag="python:not item.isSortableColumn(tableName, colName)"

versioning/browser.py

@@ -1,5 +1,5 @@
 #
-#  Copyright (c) 2007 Helmut Merz helmutm@cy55.de
+#  Copyright (c) 2015 Helmut Merz helmutm@cy55.de
 #
 #  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
@@ -18,8 +18,6 @@
 
 """
 View classes for versioning.
-
-$Id$
 """
 
 from zope import interface, component
@@ -51,8 +49,11 @@ class ListVersions(BaseView):
     def versions(self):
         versionable = IVersionable(self.context)
         versions = versionable.versions
+        cls = getattr(self.controller, 'versionViewClass', None)
         for v in sorted(versions):
-            if isinstance(versions[v], Resource):
+            if cls is not None:
+                yield(cls(versions[v], self.request))
+            elif isinstance(versions[v], Resource):
                 from loops.browser.resource import ResourceView
                 yield ResourceView(versions[v], self.request)
             else: