Index: generic/predefined.h
===================================================================
diff -u -rd56d2a8ee3f246c9891783abb09bd820dbc508e4 -r2454ab78913d0686b2ec5feeb401a051dc6a6164
--- generic/predefined.h	(.../predefined.h)	(revision d56d2a8ee3f246c9891783abb09bd820dbc508e4)
+++ generic/predefined.h	(.../predefined.h)	(revision 2454ab78913d0686b2ec5feeb401a051dc6a6164)
@@ -41,7 +41,9 @@
 "if {$what in [list \"alias\" \"forward\" \"method\" \"setter\"]} {\n"
 "return [::xotcl::dispatch [self] ::xotcl::classes::xotcl2::Object::$what {*}$args]}\n"
 "if {$what in [list \"info\"]} {\n"
-"::xotcl2::objectInfo [lindex $args 0] [self] {*}[lrange $args 1 end]}}\n"
+"return [::xotcl2::objectInfo [lindex $args 0] [self] {*}[lrange $args 1 end]]}\n"
+"if {$what in [list \"filter\" \"mixin\"]} {\n"
+"return [.object-$what {*}$args]}}\n"
 ".method unknown {m args} {\n"
 "error \"Method '$m' unknown for [self].\\\n"
 "Consider '[self] create $m $args' instead of '[self] $m $args'\"}}\n"
@@ -81,7 +83,7 @@
 "::xotcl::setter [self] $methodName -per-object}}\n"
 "Class public method setter {methodName value:optional} {\n"
 "if {[info exists value]} {\n"
-"::xotcl::setter [self] $methodName  $value} else {\n"
+"::xotcl::setter [self] $methodName $value} else {\n"
 "::xotcl::setter [self] $methodName}}\n"
 "Object create ::xotcl2::objectInfo\n"
 "Object create ::xotcl2::classInfo\n"
@@ -200,6 +202,7 @@
 "$class __invalidateobjectparameter}\n"
 "createBootstrapAttributeSlots ::xotcl::Slot {\n"
 "{name \"[namespace tail [::xotcl::self]]\"}\n"
+"{methodname \"[namespace tail [::xotcl::self]]\"}\n"
 "{domain \"[lindex [regexp -inline {^(.*)::slot::[^:]+$} [::xotcl::self]] 1]\"}\n"
 "{defaultmethods {get assign}}\n"
 "{manager \"[::xotcl::self]\"}\n"
@@ -241,8 +244,7 @@
 "set cl [expr {${.per-object} ? \"Object\" : \"Class\"}]\n"
 "::xotcl::dispatch ${.domain} ::xotcl::classes::xotcl2::${cl}::forward \\\n"
 "${.name} ${.manager} [list %1 [${.manager} defaultmethods]] %self \\\n"
-"\"%-per-object [info exists .forward-per-object]\" \\\n"
-"%proc}}\n"
+"${.methodname}}}\n"
 "::xotcl::MetaSlot create ::xotcl::InfoSlot\n"
 "createBootstrapAttributeSlots ::xotcl::InfoSlot {\n"
 "{multivalued true}\n"
@@ -253,15 +255,12 @@
 "::xotcl::InfoSlot public method add {obj prop value {pos 0}} {\n"
 "if {![set .multivalued]} {\n"
 "error \"Property $prop of ${.domain}->$obj ist not multivalued\"}\n"
-"puts stderr \"adding infoslot: $obj $prop [linsert [$obj info $prop] $pos $value]\"\n"
 "$obj $prop [linsert [$obj info $prop] $pos $value]}\n"
-"::xotcl::InfoSlot public method delete {-nocomplain:switch obj prop value} {\n"
-"puts stderr infoslot-delete-[self args]\n"
-"set old [$obj info $prop]\n"
+"::xotcl::InfoSlot protected method delete_value {obj prop old value} {\n"
 "if {[string first * $value] > -1 || [string first \\[ $value] > -1} {\n"
 "if {${.elementtype} ne \"\" && ![string match ::* $value]} {\n"
 "set value ::$value}\n"
-"return [$obj $prop [lsearch -all -not -glob -inline $old $value]]} elseif {${.elementtype} ne \"\"} {\n"
+"return [lsearch -all -not -glob -inline $old $value]} elseif {${.elementtype} ne \"\"} {\n"
 "if {[string first :: $value] == -1} {\n"
 "if {![::xotcl::is $value object]} {\n"
 "error \"$value does not appear to be an object\"}\n"
@@ -270,20 +269,23 @@
 "error \"$value does not appear to be of type ${.elementtype}\"}}\n"
 "set p [lsearch -exact $old $value]\n"
 "if {$p > -1} {\n"
-"$obj $prop [lreplace $old $p $p]} else {\n"
+"return [lreplace $old $p $p]} else {\n"
 "error \"$value is not a $prop of $obj (valid are: $old)\"}}\n"
+"::xotcl::InfoSlot public method delete {-nocomplain:switch obj prop value} {\n"
+"$obj $prop [.delete_value $obj $prop [$obj info $prop] $value]}\n"
 "::xotcl::MetaSlot alloc ::xotcl::InterceptorSlot\n"
 "::xotcl::relation ::xotcl::InterceptorSlot superclass ::xotcl::InfoSlot\n"
 "::xotcl::alias ::xotcl::InterceptorSlot set ::xotcl::relation ;# for backwards compatibility\n"
 "::xotcl::alias ::xotcl::InterceptorSlot assign ::xotcl::relation\n"
-"::xotcl::InterceptorSlot public method get {obj -per-object:switch prop} {\n"
-"::xotcl::relation $obj {*}[expr {${per-object} ? \"-per-object\" : \"\"}] $prop}\n"
-"::xotcl::InterceptorSlot public method add {obj -per-object:switch prop value {pos 0}} {\n"
+"::xotcl::InterceptorSlot public method get {obj prop} {\n"
+"::xotcl::relation $obj $prop}\n"
+"::xotcl::InterceptorSlot public method add {obj prop value {pos 0}} {\n"
 "if {![set .multivalued]} {\n"
 "error \"Property $prop of ${.domain}->$obj ist not multivalued\"}\n"
-"set perObject [expr {${per-object} ? \"-per-object\" : \"\"}]\n"
-"set oldSetting [::xotcl::relation $obj {*}$perObject $prop]\n"
-"::xotcl::relation $obj {*}$perObject $prop [linsert $oldSetting $pos $value]}\n"
+"set oldSetting [::xotcl::relation $obj $prop]\n"
+"::xotcl::relation $obj $prop [linsert $oldSetting $pos $value]}\n"
+"::xotcl::InterceptorSlot public method delete {-nocomplain:switch obj prop value} {\n"
+"::xotcl::relation $obj $prop [.delete_value $obj $prop [::xotcl::relation $obj $prop] $value]}\n"
 "proc ::xotcl::register_system_slots {os} {\n"
 "${os}::Object alloc ${os}::Class::slot\n"
 "${os}::Object alloc ${os}::Object::slot\n"
@@ -292,8 +294,16 @@
 "::xotcl::InfoSlot create ${os}::Object::slot::class -type relation\n"
 "::xotcl::alias           ${os}::Object::slot::class assign ::xotcl::relation\n"
 "::xotcl::InterceptorSlot create ${os}::Object::slot::mixin \\\n"
-"-type relation\n"
+"-type relation -methodname object-mixin\n"
 "::xotcl::InterceptorSlot create ${os}::Object::slot::filter \\\n"
+"-elementtype \"\" -type relation\n"
+"::xotcl::InterceptorSlot create ${os}::Class::slot::mixin \\\n"
+"-type relation -methodname class-mixin\n"
+"::xotcl::InterceptorSlot create ${os}::Class::slot::filter \\\n"
+"-type relation -methodname filter-mixin\n"
+"::xotcl::InterceptorSlot create ${os}::Class::slot::object-mixin \\\n"
+"-type relation\n"
+"::xotcl::InterceptorSlot create ${os}::Class::slot::object-filter \\\n"
 "-elementtype \"\" -type relation}\n"
 "::xotcl::register_system_slots ::xotcl2\n"
 "::xotcl::MetaSlot __invalidateobjectparameter\n"
Index: generic/predefined.xotcl
===================================================================
diff -u -rd56d2a8ee3f246c9891783abb09bd820dbc508e4 -r2454ab78913d0686b2ec5feeb401a051dc6a6164
--- generic/predefined.xotcl	(.../predefined.xotcl)	(revision d56d2a8ee3f246c9891783abb09bd820dbc508e4)
+++ generic/predefined.xotcl	(.../predefined.xotcl)	(revision 2454ab78913d0686b2ec5feeb401a051dc6a6164)
@@ -82,8 +82,11 @@
         return [::xotcl::dispatch [self] ::xotcl::classes::xotcl2::Object::$what {*}$args]
       }
       if {$what in [list "info"]} {
-        ::xotcl2::objectInfo [lindex $args 0] [self] {*}[lrange $args 1 end]
+        return [::xotcl2::objectInfo [lindex $args 0] [self] {*}[lrange $args 1 end]]
       }
+      if {$what in [list "filter" "mixin"]} {
+        return [.object-$what {*}$args]
+      }
     }
 
     # define unknown handler for class
@@ -170,7 +173,7 @@
 
   Class public method setter {methodName value:optional} {
     if {[info exists value]} {
-      ::xotcl::setter [self] $methodName  $value
+      ::xotcl::setter [self] $methodName $value
     } else {
       ::xotcl::setter [self] $methodName
     }
@@ -222,13 +225,8 @@
   }
   unset cmd
 
-  #Object forward info -onerror ::xotcl::infoError ::xotcl2::objectInfo %1 {%@2 %self}
-  #Class  forward info -onerror ::xotcl::infoError ::xotcl2::classInfo %1 {%@2 %self}
-
   Object forward info -onerror ::xotcl::infoError ::xotcl2::objectInfo %1 {%@2 %self}
   Class forward  info -onerror ::xotcl::infoError ::xotcl2::classInfo %1 {%@2 %self}
-#  ::xotcl::dispatch ::xotcl2::classInfo ::xotcl::cmd::Object::forward \
-#      "-per-object" -verbose ::xotcl2::objectInfo {%@2 %1}
 
   proc ::xotcl::infoError msg {
     #puts stderr "INFO ERROR: <$msg>\n$::errorInfo"
@@ -416,6 +414,7 @@
 ############################################
 createBootstrapAttributeSlots ::xotcl::Slot {
   {name "[namespace tail [::xotcl::self]]"}
+  {methodname "[namespace tail [::xotcl::self]]"}
   {domain "[lindex [regexp -inline {^(.*)::slot::[^:]+$} [::xotcl::self]] 1]"}
   {defaultmethods {get assign}}
   {manager "[::xotcl::self]"}
@@ -475,13 +474,11 @@
   }
   if {${.domain} ne ""} {
     ${.domain} __invalidateobjectparameter
-    # since the domain object might be xotcl1 or xotcl2, use dispatch
-    
     set cl [expr {${.per-object} ? "Object" : "Class"}]
+    # since the domain object might be xotcl1 or xotcl2, use dispatch
     ::xotcl::dispatch ${.domain} ::xotcl::classes::xotcl2::${cl}::forward \
         ${.name} ${.manager} [list %1 [${.manager} defaultmethods]] %self \
-        "%-per-object [info exists .forward-per-object]" \
-        %proc
+       ${.methodname}
   }
 }
 
@@ -501,19 +498,17 @@
   if {![set .multivalued]} {
     error "Property $prop of ${.domain}->$obj ist not multivalued"
   }
-  puts stderr "adding infoslot: $obj $prop [linsert [$obj info $prop] $pos $value]"
+  #puts stderr "adding infoslot: $obj $prop [linsert [$obj info $prop] $pos $value]"
   $obj $prop [linsert [$obj info $prop] $pos $value]
 }
-::xotcl::InfoSlot public method delete {-nocomplain:switch obj prop value} {
-  puts stderr infoslot-delete-[self args]
-  set old [$obj info $prop]
+::xotcl::InfoSlot protected method delete_value {obj prop old value} {
   if {[string first * $value] > -1 || [string first \[ $value] > -1} {
     # string contains meta characters
     if {${.elementtype} ne "" && ![string match ::* $value]} {
       # prefix string with ::, since all object names have leading ::
       set value ::$value
     }
-    return [$obj $prop [lsearch -all -not -glob -inline $old $value]]
+    return [lsearch -all -not -glob -inline $old $value]
   } elseif {${.elementtype} ne ""} {
     if {[string first :: $value] == -1} {
       if {![::xotcl::is $value object]} {
@@ -527,12 +522,17 @@
   }
   set p [lsearch -exact $old $value]
   if {$p > -1} {
-    $obj $prop [lreplace $old $p $p]
+    return [lreplace $old $p $p]
   } else {
     error "$value is not a $prop of $obj (valid are: $old)"
   }
 }
 
+::xotcl::InfoSlot public method delete {-nocomplain:switch obj prop value} {
+  #puts stderr infoslot-delete-[self args]
+  $obj $prop [.delete_value $obj $prop [$obj info $prop] $value]
+}
+
 ############################################
 # InterceptorSlot
 ############################################
@@ -542,17 +542,19 @@
 ::xotcl::alias ::xotcl::InterceptorSlot set ::xotcl::relation ;# for backwards compatibility
 ::xotcl::alias ::xotcl::InterceptorSlot assign ::xotcl::relation
 
-::xotcl::InterceptorSlot public method get {obj -per-object:switch prop} {
-  ::xotcl::relation $obj {*}[expr {${per-object} ? "-per-object" : ""}] $prop
+::xotcl::InterceptorSlot public method get {obj prop} {
+  ::xotcl::relation $obj $prop
 }
-::xotcl::InterceptorSlot public method add {obj -per-object:switch prop value {pos 0}} {
+::xotcl::InterceptorSlot public method add {obj prop value {pos 0}} {
   if {![set .multivalued]} {
     error "Property $prop of ${.domain}->$obj ist not multivalued"
   }
-  set perObject [expr {${per-object} ? "-per-object" : ""}]
-  set oldSetting [::xotcl::relation $obj {*}$perObject $prop]
-  ::xotcl::relation $obj {*}$perObject $prop [linsert $oldSetting $pos $value]
+  set oldSetting [::xotcl::relation $obj $prop]
+  ::xotcl::relation $obj $prop [linsert $oldSetting $pos $value]
 }
+::xotcl::InterceptorSlot public method delete {-nocomplain:switch obj prop value} {
+  ::xotcl::relation $obj $prop [.delete_value $obj $prop [::xotcl::relation $obj $prop] $value]
+}
 
 ############################################
 # system slots
@@ -567,13 +569,27 @@
   ::xotcl::alias           ${os}::Object::slot::class assign ::xotcl::relation
 
   ::xotcl::InterceptorSlot create ${os}::Object::slot::mixin \
-      -type relation
+      -type relation -methodname object-mixin
 
   ::xotcl::InterceptorSlot create ${os}::Object::slot::filter \
       -elementtype "" -type relation
 
-#  ::xotcl::InterceptorSlot create ${os}::Class::slot::object-mixin \
-#      -type relation
+  ::xotcl::InterceptorSlot create ${os}::Class::slot::mixin \
+      -type relation -methodname class-mixin
+  ::xotcl::InterceptorSlot create ${os}::Class::slot::filter \
+      -type relation -methodname filter-mixin
+
+  # create tho conveniance slots to allow configuration of 
+  # object-slots for classes via object-mixin
+  ::xotcl::InterceptorSlot create ${os}::Class::slot::object-mixin \
+      -type relation
+  ::xotcl::InterceptorSlot create ${os}::Class::slot::object-filter \
+      -elementtype "" -type relation
+
+  # We could define a mixin on class, the calls always class-mixin.
+  # therfore, 
+  #::xotcl::InterceptorSlot create ${os}::Class::slot::mixin \
+  #    -type relation -methodname class-mixin
 }
 ::xotcl::register_system_slots ::xotcl2
 
Index: generic/xotcl.c
===================================================================
diff -u -rd56d2a8ee3f246c9891783abb09bd820dbc508e4 -r2454ab78913d0686b2ec5feeb401a051dc6a6164
--- generic/xotcl.c	(.../xotcl.c)	(revision d56d2a8ee3f246c9891783abb09bd820dbc508e4)
+++ generic/xotcl.c	(.../xotcl.c)	(revision 2454ab78913d0686b2ec5feeb401a051dc6a6164)
@@ -11067,7 +11067,14 @@
 
   /*fprintf(stderr, "XOTclRelationCmd %s %d rel=%d val='%s'\n",
     objectName(object),withPer_object,relationtype,value?ObjStr(value):"NULL");*/
-  
+  /* set withPer_object according to object- or class- */
+  switch (relationtype) {
+  case RelationtypeObject_mixinIdx: withPer_object = 1; break;
+  case RelationtypeObject_filterIdx: withPer_object = 1; break;
+  case RelationtypeClass_mixinIdx: withPer_object = 0; break;
+  case RelationtypeClass_filterIdx: withPer_object = 0; break;
+  }
+
   if (withPer_object) {
     switch (relationtype) {
     case RelationtypeClass_mixinIdx:
Index: library/lib/xotcl1.xotcl
===================================================================
diff -u -rd56d2a8ee3f246c9891783abb09bd820dbc508e4 -r2454ab78913d0686b2ec5feeb401a051dc6a6164
--- library/lib/xotcl1.xotcl	(.../xotcl1.xotcl)	(revision d56d2a8ee3f246c9891783abb09bd820dbc508e4)
+++ library/lib/xotcl1.xotcl	(.../xotcl1.xotcl)	(revision 2454ab78913d0686b2ec5feeb401a051dc6a6164)
@@ -135,16 +135,15 @@
     ::xotcl::alias           ${os}::Object::slot::class assign ::xotcl::relation
 
     ::xotcl::InterceptorSlot create ${os}::Object::slot::mixin \
-        -forward-per-object true \
-        -type relation
+        -type relation -methodname object-mixin
     ::xotcl::InterceptorSlot create ${os}::Object::slot::filter \
-        -forward-per-object true \
-        -elementtype "" -type relation
+        -type relation  -methodname object-filter \
+        -elementtype ""
     ::xotcl::InterceptorSlot create ${os}::Class::slot::instmixin \
-        -type relation
+        -type relation  -methodname class-mixin
     ::xotcl::InterceptorSlot create ${os}::Class::slot::instfilter \
-        -elementtype "" \
-        -type relation
+        -type relation -methodname class-filter \
+        -elementtype ""
   }
   ::xotcl::register_system_slots1 ::xotcl
 
Index: tests/interceptor-slot.xotcl
===================================================================
diff -u -rd56d2a8ee3f246c9891783abb09bd820dbc508e4 -r2454ab78913d0686b2ec5feeb401a051dc6a6164
--- tests/interceptor-slot.xotcl	(.../interceptor-slot.xotcl)	(revision d56d2a8ee3f246c9891783abb09bd820dbc508e4)
+++ tests/interceptor-slot.xotcl	(.../interceptor-slot.xotcl)	(revision 2454ab78913d0686b2ec5feeb401a051dc6a6164)
@@ -1,7 +1,7 @@
 package require XOTcl
 package require xotcl::test
+::xotcl::use xotcl2
 
-
 proc ? {cmd expected {msg ""}} {
   set count 10
   if {$msg ne ""} {
@@ -13,15 +13,14 @@
   $t run
 }
 
-::xotcl::use xotcl2
 puts stderr START
 Class create M {
   .method mfoo {} {puts [self proc]}
 }
 Class create M2
 Class create C 
-? {C info callable -which mixin} "::xotcl2::Object forward mixin ::xotcl2::Object::slot::mixin {%1 {get assign}} %self {%-per-object 0} %proc"
-#? {C info callable -which mixin} "::xotcl2::Object forward mixin ::xotcl2::Object::slot::mixin {%1 {get assign}} %self %proc"
+
+? {C info callable -which mixin} "::xotcl2::Class forward mixin ::xotcl2::Class::slot::mixin {%1 {get assign}} %self class-mixin"
 C mixin M
 ? {C info precedence} "::xotcl2::Class ::xotcl2::Object"
 ? {C mixin} "::M"
@@ -33,12 +32,14 @@
 C mixin delete M2
 ? {c1 info precedence} "::M ::C ::xotcl2::Object"
 C mixin delete M
+
 # per-object mixins
 ? {c1 info precedence} "::C ::xotcl2::Object"
 c1 mixin add M
 ? {::xotcl::relation c1 mixin} ::M
 ? {catch {c1 mixin UNKNOWN}} 1
 ? {::xotcl::relation c1 mixin} "::M"
+
 # add again the same mixin
 c1 mixin add M
 ? {c1 info precedence} "::M ::C ::xotcl2::Object"
@@ -49,9 +50,9 @@
 c1 mixin delete M2
 ? {c1 info precedence} "::C ::xotcl2::Object"
 
-
 #
-# adding, removing per-object mixins for classes through relation 
+# adding, removing per-object mixins for classes through relation
+# "mixin" and "-per-object" (deprecated)
 #
 ::xotcl::relation C -per-object mixin M
 ? {C info precedence} "::M ::xotcl2::Class ::xotcl2::Object"
@@ -60,24 +61,63 @@
 ? {C info precedence} "::xotcl2::Class ::xotcl2::Object"
 
 #
-# adding per-object mixins for classes via "mixin -per-object add M"
+# adding, removing per-object mixins for classes through relation
+# "object-mixin"
 #
-C mixin -per-object add M 
+::xotcl::relation C object-mixin M
 ? {C info precedence} "::M ::xotcl2::Class ::xotcl2::Object"
-? {::xotcl::relation C -per-object mixin} ::M
-? {catch {C mixin -per-object add UNKNOWN}} 1
-? {::xotcl::relation C -per-object mixin} "::M"
-C mixin -per-object ""
+? {C object info mixin} "::M"
+::xotcl::relation C object-mixin ""
 ? {C info precedence} "::xotcl2::Class ::xotcl2::Object"
 
 #
-# adding per-object mixins for classes via "mixin -per-object M"
+# adding, removing per-object mixins for classes through slot
+# "object-mixin"
 #
-C mixin -per-object M 
+C object-mixin M
 ? {C info precedence} "::M ::xotcl2::Class ::xotcl2::Object"
+? {C object info mixin} "::M"
+C object-mixin ""
+? {C info precedence} "::xotcl2::Class ::xotcl2::Object"
 
+#
+# add and remove object mixin for classes via modifier "object" and
+# "mixin"
+#
+C object mixin M
+? {C info precedence} "::M ::xotcl2::Class ::xotcl2::Object"
+? {C object info mixin} "::M"
+C object mixin ""
+? {C info precedence} "::xotcl2::Class ::xotcl2::Object"
+
+#
+#  add and remove object mixin for classes via object mixin add
+#
+C object mixin add M
+? {C info precedence} "::M ::xotcl2::Class ::xotcl2::Object"
+? {C object info mixin} "::M"
+C object mixin ""
+? {C info precedence} "::xotcl2::Class ::xotcl2::Object"
+
+#
+# adding per-object mixins for classes via "object mixin add M"
+#
+C object mixin add M 
+? {C info precedence} "::M ::xotcl2::Class ::xotcl2::Object"
+? {::xotcl::relation C object-mixin} ::M
+? {catch {C object mixin add UNKNOWN}} 1
+? {::xotcl::relation C object-mixin} "::M"
+C object mixin ""
+? {C info precedence} "::xotcl2::Class ::xotcl2::Object"
+
+#
+# adding per-object mixins for classes via "object mixin M"
+#
+C object mixin M 
+? {C info precedence} "::M ::xotcl2::Class ::xotcl2::Object"
+
 # forwarder with 0 arguments + flag
-? {C mixin -per-object} "::M"
+? {C object-mixin} "::M"
 
 puts stderr "==================== XOTcl 1"
 ::xotcl::use xotcl1