Index: library/nx/nx.tcl
===================================================================
diff -u -rd9c5a4b5c33bfa0bdb33ef52bd703390d933eb98 -rd9b42d77f43db84a9983cc3bbc4124cf0b52df29
--- library/nx/nx.tcl	(.../nx.tcl)	(revision d9c5a4b5c33bfa0bdb33ef52bd703390d933eb98)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision d9b42d77f43db84a9983cc3bbc4124cf0b52df29)
@@ -347,7 +347,7 @@
       set methodName [lindex $path end]
       foreach w [lrange $path 0 end-1] {
 	#puts stderr "check $object info methods $path @ <$w>"
-	set scope [expr {[nsf::objectproperty class $object] && !${per-object} ? "Class" : "Object"}] 
+	set scope [expr {[nsf::is class $object] && !${per-object} ? "Class" : "Object"}] 
 	if {[$object ::nsf::cmd::${scope}Info::methods -methodtype all $w] eq ""} {
 	  #
 	  # Create dispatch/ensemble object and accessor method (if wanted)
@@ -756,7 +756,7 @@
       set parent [::nsf::dispatch $self ::nsf::cmd::ObjectInfo::parent]
       set grandparent [::nsf::dispatch $parent ::nsf::cmd::ObjectInfo::parent]
       set tail [namespace tail $parent]
-      if {$tail eq "slot" && [::nsf::objectproperty class $grandparent]} {
+      if {$tail eq "slot" && [::nsf::is class $grandparent]} {
 	set aliases [::nsf::dispatch $grandparent ::nsf::cmd::ClassInfo::methods -methodtype alias]
 	foreach alias $aliases {
 	  set def [::nsf::dispatch $grandparent ::nsf::cmd::ClassInfo::method definition $alias]
@@ -778,7 +778,7 @@
       set path $(name)
       while {1} {
 	set o [::nsf::dispatch $o ::nsf::cmd::ObjectInfo::parent]
-	if {![::nsf::objectproperty type $o ::nx::EnsembleObject]} break
+	if {![$o has type ::nx::EnsembleObject]} break
 	array set "" [$o ::nsf::classes::nx::EnsembleObject::subcmdName]
 	set path "$(name) $path"
       }
@@ -853,7 +853,7 @@
     :alias "info has mixin"      ::nsf::cmd::ObjectInfo::hasmixin
     :alias "info has namespace"  ::nsf::cmd::ObjectInfo::hasnamespace
     :alias "info has type"       ::nsf::cmd::ObjectInfo::hastype
-    :method "info is" {kind}     {::nsf::objectproperty $kind [::nsf::current object]}
+    :alias "info is"             ::nsf::cmd::ObjectInfo::istype
     :alias "info methods"        ::nsf::cmd::ObjectInfo::methods
     :alias "info mixin guard"    ::nsf::cmd::ObjectInfo::mixinguard
     :alias "info mixin classes"  ::nsf::cmd::ObjectInfo::mixinclasses
@@ -1216,7 +1216,7 @@
   }
   
   ObjectParameterSlot public method destroy {} {
-    if {${:domain} ne "" && [::nsf::objectproperty class ${:domain}]} {
+    if {${:domain} ne "" && [::nsf::is class ${:domain}]} {
       ::nsf::invalidateobjectparameter ${:domain}
     }
     ::nsf::next
@@ -1230,7 +1230,7 @@
       if {![info exists :methodname]} {
         set :methodname ${:name}
       }
-      if {[::nsf::objectproperty class ${:domain}]} {
+      if {[::nsf::is class ${:domain}]} {
 	::nsf::invalidateobjectparameter ${:domain}
       } 
       if {${:per-object} && [info exists :default] } {
@@ -1273,7 +1273,7 @@
     }
     if {[info exists :type]} {
       if {[string match ::* ${:type}]} {
-	set type [expr {[::nsf::objectproperty metaclass ${:type}] ? "class" : "object"}]
+	set type [expr {[::nsf::is metaclass ${:type}] ? "class" : "object"}]
         lappend objopts type=${:type}
         lappend methodopts type=${:type}
       } else {
@@ -1340,7 +1340,7 @@
       if {![::nsf::dispatch $slot ::nsf::cmd::ObjectInfo::hastype ::nx::Slot]} continue
       # Skip some slots for xotcl; 
       # TODO: maybe different parameterFromSlots for xotcl?
-      if {[::nsf::is ::xotcl::Object class] 
+      if {[::nsf::is class ::xotcl::Object] 
 	  && [::nsf::dispatch $obj ::nsf::cmd::ObjectInfo::hastype ::xotcl::Object] && 
           ([$slot name] eq "mixin" || [$slot name] eq "filter")
 	} continue
@@ -1354,7 +1354,7 @@
   Object protected method objectparameter {{lastparameter __initcmd:initcmd,optional}} {
     #puts stderr "... objectparameter [::nsf::current object]"
     set parameterdefinitions [::nsf::parametersFromSlots [::nsf::current object]]
-    if {[::nsf::objectproperty class [::nsf::current object]]} {
+    if {[::nsf::is class [::nsf::current object]]} {
       lappend parameterdefinitions -parameter:method,optional
     }
     lappend parameterdefinitions \
@@ -1406,7 +1406,7 @@
         }
         set value [::nsf::dispatch $value -objscope ::nsf::current object]
       }
-      if {![::nsf::objectproperty class ${:elementtype}]} {
+      if {![::nsf::is class ${:elementtype}]} {
         error "$value does not appear to be of type ${:elementtype}"
       }
     }
@@ -1778,14 +1778,15 @@
   ##################################################################
 
   Slot method type=baseclass {name value} {
-    if {![::nsf::objectproperty baseclass $value]} {
+    # note, that we cannot use "nsf::is baseclass ..." here, since nsf::is call this converter
+    if {![::nsf::isobject $value] || ![::nsf::dispatch $value ::nsf::cmd::ObjectInfo::istype baseclass]} {
       error "expected baseclass but got \"$value\" for parameter $name"
     }
     return $value
   }
 
   Slot method type=metaclass {name value} {
-    if {![::nsf::objectproperty metaclass $value]} {
+    if {![::nsf::isobject $value] || ![::nsf::dispatch $value ::nsf::cmd::ObjectInfo::istype metaclass]} {
       error "expected metaclass but got \"$value\" for parameter $name"
     }
     return $value
@@ -1837,10 +1838,10 @@
       Class mixin add $m end
       # TODO: the following is not pretty; however, contains might
       # build xotcl and next objects.
-      if {[::nsf::is ::xotcl::Class class]} {::xotcl::Class instmixin add $m end}
+      if {[::nsf::is class ::xotcl::Class]} {::xotcl::Class instmixin add $m end}
       namespace eval $object $cmds
       Class mixin delete $m
-      if {[::nsf::is ::xotcl::Class class]} {::xotcl::Class instmixin delete $m}
+      if {[::nsf::is class ::xotcl::Class]} {::xotcl::Class instmixin delete $m}
     } else {
       namespace eval $object $cmds
     }
@@ -1906,7 +1907,7 @@
         set dest [:getDest $origin]
         if {[::nsf::isobject $origin]} {
           # copy class information
-          if {[::nsf::objectproperty class $origin]} {
+          if {[::nsf::is class $origin]} {
             set cl [[$origin info class] create $dest -noinit]
             # class object
             set obj $cl
@@ -1936,7 +1937,7 @@
 	  ::nsf::forward $dest -per-object $i {*}[$origin ::nsf::cmd::ObjectInfo::forward -definition $i]
 
 	}
-	if {[::nsf::objectproperty class $origin]} {
+	if {[::nsf::is class $origin]} {
 	  foreach i [$origin ::nsf::cmd::ClassInfo::forward] {
 	    ::nsf::forward $dest $i {*}[$origin ::nsf::cmd::ClassInfo::forward -definition $i]
 	  }
@@ -1959,7 +1960,7 @@
       }
       # alter 'domain' and 'manager' in slot objects for classes
       foreach origin [set :targetList] {
-	if {[::nsf::objectproperty class $origin]} {
+	if {[::nsf::is class $origin]} {
 	  set dest [:getDest $origin]
 	  foreach oldslot [$origin info slots] {
 	    set newslot [::nx::slotObj $dest [namespace tail $oldslot]] 
@@ -1992,7 +1993,7 @@
         :copy $newName
       }
       ### let all subclasses get the copied class as superclass
-      if {[::nsf::objectproperty class [::nsf::current object]] && $newName ne ""} {
+      if {[::nsf::is class [::nsf::current object]] && $newName ne ""} {
         foreach subclass [:info subclass] {
           set scl [$subclass info superclass]
           if {[set index [lsearch -exact $scl [::nsf::current object]]] != -1} {