Index: TODO
===================================================================
diff -u -r0aeccfecef90977dbe8f105c4e808f7f5313486f -r27030b244334e022169ea7143ce6d91257a8b653
--- TODO	(.../TODO)	(revision 0aeccfecef90977dbe8f105c4e808f7f5313486f)
+++ TODO	(.../TODO)	(revision 27030b244334e022169ea7143ce6d91257a8b653)
@@ -5094,13 +5094,18 @@
 nx.tcl:
 - add slot method value=unset to nx::RelationSlot and nx::VariableSlot
 - extended regression test
+- reworked error message generation of slot-forwarder 
+  (list all available slot methods with prefix value=)
 
+xotcl2:
+- use xotcl::RelationSlot instead of nx::Relationslot in xotcl2
+  (we can more value=assign here).
+
 Makefile:
 - fix load paths for sublibs (e.g. mongodb) in regression test
 
 ========================================================================
 TODO:
-- TODO: rework error message generation of slot-forwarder
 - TODO: demangle "slotassign" in "ObjectParameterSlot protected method getParameterOptions" 
   and check interactions
 - TODO: clean up relation slot mixin variants
Index: library/nx/nx.tcl
===================================================================
diff -u -r59f13181ba70df745dca1c5e96ed872703d8662d -r27030b244334e022169ea7143ce6d91257a8b653
--- library/nx/nx.tcl	(.../nx.tcl)	(revision 59f13181ba70df745dca1c5e96ed872703d8662d)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision 27030b244334e022169ea7143ce6d91257a8b653)
@@ -1333,8 +1333,11 @@
 
   ObjectParameterSlot public method onError {cmd msg} {
     if {[string match "%1 requires argument*" $msg]} {
-      #return -code error "wrong # args: use \"$cmd assign|get\" [lsort [:info lookup methods -callprotection public -source application]]" 
-      return -code error "wrong # args: use \"$cmd assign|get\"" 
+      set methods ""
+      foreach m [lsort [:info lookup methods -callprotection public value=*]] {
+        lappend methods [lindex [split $m =] end]
+      }
+      return -code error "wrong # args: use \"$cmd [join $methods |]\"" 
     }
     return -code error $msg
   }
@@ -1388,7 +1391,7 @@
       # Slot objects are always in nx (for nx and for xotcl
       # application objects. we have to watch for assign and set)
       #
-      if {[:info lookup method value=assign] ni {"" "::nsf::classes::nx::RelationSlot::value=assign"}} {
+      if {[:info lookup method value=assign] ni {"" "::nsf::classes::xotcl::RelationSlot::value=assign"}} {
 	# In case the "assign" method was provided on the slot, ask nsf to call it directly
 	lappend options slot=[::nsf::self] slotassign
       } elseif {[:info lookup method value=set] ni {"" "::nsf::classes::nx::RelationSlot::value=set"}} {
@@ -1528,7 +1531,6 @@
   #
   # create methods for slot operations assign/get/add/delete
   #
-  ::nsf::method::alias RelationSlot value=assign ::nsf::relation
   ::nsf::method::alias RelationSlot value=set ::nsf::relation
   ::nsf::method::alias RelationSlot value=get ::nsf::relation
 
Index: library/xotcl/library/xotcl2.tcl
===================================================================
diff -u -r5d3bc04b5ec0a4422236a65220d94ceee17a8796 -r27030b244334e022169ea7143ce6d91257a8b653
--- library/xotcl/library/xotcl2.tcl	(.../xotcl2.tcl)	(revision 5d3bc04b5ec0a4422236a65220d94ceee17a8796)
+++ library/xotcl/library/xotcl2.tcl	(.../xotcl2.tcl)	(revision 27030b244334e022169ea7143ce6d91257a8b653)
@@ -481,24 +481,28 @@
   # We need fully qualified "::xotcl" prefixes, since prefix
   # completion would skip the object system root namespace
 
+  nx::MetaSlot create ::xotcl::RelationSlot -superclass ::nx::RelationSlot
+
+  ::nsf::method::alias ::xotcl::RelationSlot value=assign ::nsf::relation
+
   set cSlotContainer [::nx::slotObj ::xotcl::Class]
   set oSlotContainer [::nx::slotObj ::xotcl::Object]
-  ::nx::RelationSlot create ${cSlotContainer}::superclass \
+  ::xotcl::RelationSlot create ${cSlotContainer}::superclass \
       -defaultmethods {get set}
   #::nsf::method::alias      ${cSlotContainer}::superclass value=set ::nsf::relation
-  ::nx::RelationSlot create ${oSlotContainer}::class -elementtype class -multiplicity 1..1 \
+  ::xotcl::RelationSlot create ${oSlotContainer}::class -elementtype class -multiplicity 1..1 \
       -defaultmethods {get set}
   #::nsf::method::alias      ${oSlotContainer}::class value=set ::nsf::relation
-  ::nx::RelationSlot create ${oSlotContainer}::mixin  -forwardername object-mixin \
+  ::xotcl::RelationSlot create ${oSlotContainer}::mixin  -forwardername object-mixin \
       -defaultmethods {get set} \
       -elementtype mixinreg -multiplicity 0..n
-  ::nx::RelationSlot create ${oSlotContainer}::filter -forwardername object-filter \
+  ::xotcl::RelationSlot create ${oSlotContainer}::filter -forwardername object-filter \
       -defaultmethods {get set} \
       -elementtype filterreg -multiplicity 0..n
-  ::nx::RelationSlot create ${cSlotContainer}::instmixin  -forwardername class-mixin \
+  ::xotcl::RelationSlot create ${cSlotContainer}::instmixin  -forwardername class-mixin \
       -defaultmethods {get set} \
       -elementtype mixinreg -multiplicity 0..n
-  ::nx::RelationSlot create ${cSlotContainer}::instfilter -forwardername class-filter \
+  ::xotcl::RelationSlot create ${cSlotContainer}::instfilter -forwardername class-filter \
       -defaultmethods {get set} \
       -elementtype filterreg -multiplicity 0..n
 
Index: tests/methods.test
===================================================================
diff -u -rdd169437c7a701da0063a40978614e6148d71221 -r27030b244334e022169ea7143ce6d91257a8b653
--- tests/methods.test	(.../methods.test)	(revision dd169437c7a701da0063a40978614e6148d71221)
+++ tests/methods.test	(.../methods.test)	(revision 27030b244334e022169ea7143ce6d91257a8b653)
@@ -235,8 +235,8 @@
   ? {lsort [C object mixin get]} "::M2 ::M4"
   ? {lsort [C mixin get]} "::M1 ::M3"
 
-  ? {lsort [C object mixin]} {wrong # args: use "::C mixin assign|get"} ;# TODO: should be "C object mixin ..."
-  ? {lsort [C mixin]} {wrong # args: use "::C mixin assign|get"}
+  ? {lsort [C object mixin]} {wrong # args: use "::C mixin add|delete|get|guard|set|unset"} ;# TODO: should be "C object mixin ..."
+  ? {lsort [C mixin]} {wrong # args: use "::C mixin add|delete|get|guard|set|unset"}
 
   ? {catch {C mixin M5} errorMsg} 1
   ? {lsort [C info mixin classes]} "::M1 ::M3"
@@ -455,7 +455,7 @@
   }
 
   # dispatch methods without current object 
-  ? ::o::a {wrong # args: use "::o ::o::a assign|get"}
+  ? ::o::a {wrong # args: use "::o ::o::a add|delete|get|set|unset"}
   ? ::o::b "::o2"
   ? ::o::foo "no current object; command called outside the context of a Next Scripting method"
   ? ::o::x "no current object; x called outside the context of a Next Scripting method"