Index: Makefile.in
===================================================================
diff -u -rcaba76f5ac2943f5a3dfd33550cb578132f40c80 -r59f13181ba70df745dca1c5e96ed872703d8662d
--- Makefile.in	(.../Makefile.in)	(revision caba76f5ac2943f5a3dfd33550cb578132f40c80)
+++ Makefile.in	(.../Makefile.in)	(revision 59f13181ba70df745dca1c5e96ed872703d8662d)
@@ -524,6 +524,7 @@
 	$(TCLSH) $(src_test_dir_native)/destroy.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/methods.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/method-parameter.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
+	$(TCLSH) $(src_test_dir_native)/accessor.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/cget.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/properties.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/var-access.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
Index: TODO
===================================================================
diff -u -r4744ebb4e03c140e81e49c56c406774d55e476ce -r59f13181ba70df745dca1c5e96ed872703d8662d
--- TODO	(.../TODO)	(revision 4744ebb4e03c140e81e49c56c406774d55e476ce)
+++ TODO	(.../TODO)	(revision 59f13181ba70df745dca1c5e96ed872703d8662d)
@@ -5051,6 +5051,7 @@
       overwrote the error message in the interp result
 
 nx.tcl:
+    - replace empty-named arrays by dicts
     - remove setter methods from BootstrapVariableSlots
     - reducing interface of BootstrapVariableSlots by setting methods protected
     - use value=* as names for interally called and forwarder-called
@@ -5090,6 +5091,9 @@
 nx::test:
     - don't delete system slot ::xotcl::Attribute on cleanup
 
+nx.tcl:
+- add slot method value=unset to nx::RelationSlot and nx::VariableSlot
+- extended regression test
 
 ========================================================================
 TODO:
Index: library/nx/nx.tcl
===================================================================
diff -u -r5d3bc04b5ec0a4422236a65220d94ceee17a8796 -r59f13181ba70df745dca1c5e96ed872703d8662d
--- library/nx/nx.tcl	(.../nx.tcl)	(revision 5d3bc04b5ec0a4422236a65220d94ceee17a8796)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision 59f13181ba70df745dca1c5e96ed872703d8662d)
@@ -1532,6 +1532,10 @@
   ::nsf::method::alias RelationSlot value=set ::nsf::relation
   ::nsf::method::alias RelationSlot value=get ::nsf::relation
 
+  RelationSlot public method value=unset {obj prop} {
+    ::nsf::relation $obj $prop {}
+  }
+
   RelationSlot protected method delete_value {obj prop old value} {
     #
     # Helper method for the delete operation, deleting a value from a
@@ -2105,6 +2109,11 @@
 
   ::nsf::method::alias ::nx::VariableSlot value=get    ::nsf::var::set
   ::nsf::method::alias ::nx::VariableSlot value=set    ::nsf::var::set
+  
+  ::nx::VariableSlot public method value=unset {obj prop} {
+    puts stderr "::nsf::var::unset $obj $prop"
+    ::nsf::var::unset $obj $prop
+  }
 
   ::nx::VariableSlot public method value=add {obj prop value {pos 0}} {
     if {![:isMultivalued]} {
Index: tests/interceptor-slot.test
===================================================================
diff -u -rd4bf05d3f89dd055bb5c86cb7f3f82ca2321473c -r59f13181ba70df745dca1c5e96ed872703d8662d
--- tests/interceptor-slot.test	(.../interceptor-slot.test)	(revision d4bf05d3f89dd055bb5c86cb7f3f82ca2321473c)
+++ tests/interceptor-slot.test	(.../interceptor-slot.test)	(revision 59f13181ba70df745dca1c5e96ed872703d8662d)
@@ -25,7 +25,12 @@
   ? {c1 info precedence} "::M ::C ::nx::Object"
   ? {C mixin delete M} ""
   ? {C info mixin classes} ""
+
   ? {C mixin set ::M} "::M"
+  ? {C mixin unset} ""
+  ? {C info mixin classes} ""
+
+  ? {C mixin add ::M} "::M"
   ? {C mixin set {}} ""
   ? {C info mixin classes} ""
 }
@@ -61,6 +66,11 @@
   ? {c1 info precedence} "::M2 ::C ::nx::Object"
   ? {c1 object mixin delete M2} ""
   ? {c1 info precedence} "::C ::nx::Object"
+
+  ? {c1 object mixin add M} {::M}
+  ? {c1 info object mixin classes} {::M}
+  ? {c1 object mixin unset} {}
+  ? {c1 info object mixin classes} {}
 }
 
 #
@@ -164,14 +174,18 @@
   ? {::nsf::relation cc object-filter filterA} filterA
   ? {cc info object filter methods} "filterA"
   ? {cc object filter set filterB} "filterB"
+
   ? {::nsf::relation cc object-filter} "filterB"
   ? {cc info object filter methods} "filterB"
+
   ? {cc object filter add filterD} "filterD filterB"
   ? {::nsf::relation cc object-filter} "filterD filterB"
   ? {cc info object filter methods} "filterD filterB"
+
   ? {cc object filter delete filterB} "filterD"
   ? {::nsf::relation cc object-filter} "filterD"
   ? {cc info object filter methods} "filterD"
+
   ? {catch {::nsf::relation cc object-filter UNKNOWN}} 1
   ? {::nsf::relation cc object-filter} "filterD"
   ? {cc info object filter methods} "filterD"
@@ -181,7 +195,8 @@
   ? {::nsf::relation CC object-filter filterC} "filterC"
   ? {::nsf::relation CC object-filter} "filterC"
   ? {CC info object filter methods} "filterC"
-  ? {::nsf::relation CC object-filter ""} ""
+
+  ? {CC object filter unset} ""
   ? {::nsf::relation CC object-filter} ""
   ? {CC info object filter methods} ""
   
@@ -190,16 +205,20 @@
   ? {::nsf::relation CC class-filter filterA} "filterA"
   ? {::nsf::relation CC class-filter} "filterA"
   ? {CC info filter methods} "filterA"
+
   ? {CC filter add filterB} "filterB filterA"
   ? {::nsf::relation CC class-filter} "filterB filterA"
   ? {CC info filter methods} "filterB filterA"
+
   ? {CC filter delete filterA} "filterB"
   ? {::nsf::relation CC class-filter} "filterB"
   ? {CC info filter methods} "filterB"
+
   ? {catch {::nsf::relation CC class-filter UNKNOWN}} 1
   ? {::nsf::relation CC class-filter} "filterB"
   ? {CC info filter methods} "filterB"
-  ? {::nsf::relation CC class-filter ""} ""
+
+  ? {CC filter unset} ""
   ? {::nsf::relation CC class-filter} ""
   ? {CC info filter methods} ""
 }