Index: openacs-4/packages/xotcl-core/tcl/30-widget-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-core/tcl/30-widget-procs.tcl,v
diff -u -N -r1.70.2.1 -r1.70.2.2
--- openacs-4/packages/xotcl-core/tcl/30-widget-procs.tcl	29 Mar 2019 20:53:24 -0000	1.70.2.1
+++ openacs-4/packages/xotcl-core/tcl/30-widget-procs.tcl	18 Apr 2019 08:04:27 -0000	1.70.2.2
@@ -414,6 +414,22 @@
     }
   }
 
+  Table ad_instproc column_names {} {
+    
+    Return a list of names of the columns of the current table.  These
+    names are used to refer to the columns, e.g. in sorting or when
+    values are set.
+
+    @return list of names
+    
+  } {
+    set names {}
+    foreach c [[[self]::__columns] children] {
+      lappend names [$c name]
+    }
+    return $names
+  }
+
   Table instproc render_with {renderer trn_mixin} {
     #:log "-- renderer=$renderer"
     set cl [self class]