Index: generic/gentclAPI.decls
===================================================================
diff -u -r12f68a7ade25ae2bb0fccb8a88583fc0d22edda0 -r4a478eb598eea7cc8dec70222777d114c55f1ff8
--- generic/gentclAPI.decls	(.../gentclAPI.decls)	(revision 12f68a7ade25ae2bb0fccb8a88583fc0d22edda0)
+++ generic/gentclAPI.decls	(.../gentclAPI.decls)	(revision 4a478eb598eea7cc8dec70222777d114c55f1ff8)
@@ -138,6 +138,10 @@
   {-argName "-per-object"}
   {-argName "methodName" -required 1}
 }
+xotclCmd valuecheck XOTclValuecheckCmd {
+  {-argName "param" -type tclobj}
+  {-argName "value" -required 0 -type tclobj}
+}
 #
 # object methods
 #
Index: generic/tclAPI.h
===================================================================
diff -u -rfe19549734064c3a57866e7e47743ec787f647e5 -r4a478eb598eea7cc8dec70222777d114c55f1ff8
--- generic/tclAPI.h	(.../tclAPI.h)	(revision fe19549734064c3a57866e7e47743ec787f647e5)
+++ generic/tclAPI.h	(.../tclAPI.h)	(revision 4a478eb598eea7cc8dec70222777d114c55f1ff8)
@@ -186,6 +186,7 @@
 static int XOTclRelationCmdStub(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv []);
 static int XOTclSetInstvarCmdStub(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv []);
 static int XOTclSetterCmdStub(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv []);
+static int XOTclValuecheckCmdStub(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv []);
 
 static int XOTclCheckBooleanArgs(Tcl_Interp *interp, char *name, Tcl_Obj *value);
 static int XOTclCheckRequiredArgs(Tcl_Interp *interp, char *name, Tcl_Obj *value);
@@ -268,6 +269,7 @@
 static int XOTclRelationCmd(Tcl_Interp *interp, XOTclObject *object, int relationtype, Tcl_Obj *value);
 static int XOTclSetInstvarCmd(Tcl_Interp *interp, XOTclObject *object, Tcl_Obj *variable, Tcl_Obj *value);
 static int XOTclSetterCmd(Tcl_Interp *interp, XOTclObject *object, int withPer_object, char *methodName);
+static int XOTclValuecheckCmd(Tcl_Interp *interp, Tcl_Obj *param, Tcl_Obj *value);
 
 enum {
  XOTclCheckBooleanArgsIdx,
@@ -350,7 +352,8 @@
  XOTclQualifyObjCmdIdx,
  XOTclRelationCmdIdx,
  XOTclSetInstvarCmdIdx,
- XOTclSetterCmdIdx
+ XOTclSetterCmdIdx,
+ XOTclValuecheckCmdIdx
 } XOTclMethods;
 
 
@@ -1959,6 +1962,25 @@
   }
 }
 
+static int
+XOTclValuecheckCmdStub(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv[]) {
+  parseContext pc;
+
+  if (ArgumentParse(interp, objc, objv, NULL, objv[0], 
+                     method_definitions[XOTclValuecheckCmdIdx].paramDefs, 
+                     method_definitions[XOTclValuecheckCmdIdx].nrParameters, 
+                     &pc) != TCL_OK) {
+    return TCL_ERROR;
+  } else {
+    Tcl_Obj *param = (Tcl_Obj *)pc.clientData[0];
+    Tcl_Obj *value = (Tcl_Obj *)pc.clientData[1];
+
+    parseContextRelease(&pc);
+    return XOTclValuecheckCmd(interp, param, value);
+
+  }
+}
+
 static methodDefinition method_definitions[] = {
 {"::xotcl::cmd::ParameterType::type=boolean", XOTclCheckBooleanArgsStub, 2, {
   {"name", 1, 0, convertToString},
@@ -2320,6 +2342,10 @@
   {"object", 1, 0, convertToObject},
   {"-per-object", 0, 0, convertToString},
   {"methodName", 1, 0, convertToString}}
+},
+{"::xotcl::valuecheck", XOTclValuecheckCmdStub, 2, {
+  {"param", 0, 0, convertToTclobj},
+  {"value", 0, 0, convertToTclobj}}
 },{NULL}
 };
 
Index: generic/xotcl.c
===================================================================
diff -u -r4ce2a0659cf44b3dbb7262f63fadb3333c968751 -r4a478eb598eea7cc8dec70222777d114c55f1ff8
--- generic/xotcl.c	(.../xotcl.c)	(revision 4ce2a0659cf44b3dbb7262f63fadb3333c968751)
+++ generic/xotcl.c	(.../xotcl.c)	(revision 4a478eb598eea7cc8dec70222777d114c55f1ff8)
@@ -12061,6 +12061,86 @@
   }
   return result;
 }
+
+static void ParamFreeInternalRep(register Tcl_Obj *objPtr);
+static int ParamSetFromAny(Tcl_Interp *interp,	register Tcl_Obj *objPtr);
+static Tcl_ObjType paramObjType = {
+    "xotclParam",				/* name */
+    ParamFreeInternalRep,		/* freeIntRepProc */
+    NULL,				/* dupIntRepProc */
+    NULL,				/* updateStringProc */
+    ParamSetFromAny			/* setFromAnyProc */
+};
+
+static void
+ParamFreeInternalRep(
+    register Tcl_Obj *objPtr)	/* Param structure object with internal
+				 * representation to free. */
+{
+  XOTclParam *paramPtr = (XOTclParam *) objPtr->internalRep.twoPtrValue.ptr1;
+  if (paramPtr != NULL) {
+    /*fprintf(stderr, "freeing %p\n",paramPtr);*/
+    ParamsFree(paramPtr);
+  }
+}
+
+static int
+ParamSetFromAny(
+    Tcl_Interp *interp,		/* Used for error reporting if not NULL. */
+    register Tcl_Obj *objPtr)	/* The object to convert. */
+{
+  XOTclParam *paramPtr;
+  Tcl_Obj *fullParamObj = Tcl_NewStringObj("value:", 6);
+  int result, possibleUnknowns = 0, plainParams = 0;
+
+  paramPtr = ParamsNew(1);
+  /*fprintf(stderr, "allocating  %p\n",paramPtr);*/
+
+  Tcl_AppendToObj(fullParamObj, ObjStr(objPtr), -1);
+  INCR_REF_COUNT(fullParamObj);
+  result = ParamParse(interp, "valuecheck", fullParamObj, 
+                      XOTCL_ARG_METHOD_PARAMETER /* allowed options */,
+                      paramPtr, &possibleUnknowns, &plainParams);
+  if (result == TCL_OK) {
+    TclFreeIntRep(objPtr);
+    objPtr->internalRep.twoPtrValue.ptr1 = (void *)paramPtr;
+    objPtr->internalRep.twoPtrValue.ptr2 = NULL;
+    objPtr->typePtr = &paramObjType;    
+  }
+
+  DECR_REF_COUNT(fullParamObj);
+  return result;
+}
+
+/*
+xotclCmd valuecheck XOTclValuecheckCmd {
+  {-argName "param" -type tclobj}
+  {-argName "value" -required 0 -type tclobj}
+  } */
+static int XOTclValuecheckCmd(Tcl_Interp *interp, Tcl_Obj *objPtr, Tcl_Obj *value) {
+  /* xxxx */
+  ClientData checkedData;
+  XOTclParam *paramPtr;
+  int result;
+
+  if (objPtr->typePtr == &paramObjType) {
+    paramPtr = (XOTclParam *) objPtr->internalRep.twoPtrValue.ptr1;
+  } else {
+    result = ParamSetFromAny(interp, objPtr);
+    if (result == TCL_OK) {
+      paramPtr = (XOTclParam *) objPtr->internalRep.twoPtrValue.ptr1;
+    } else {
+      return XOTclVarErrMsg(interp,
+                            "invalid value constraints \"", ObjStr(objPtr), "\"",
+                            (char *) NULL);
+    }
+  }
+
+  result = ArgumentCheck(interp, value, paramPtr, &checkedData);
+  Tcl_SetIntObj(Tcl_GetObjResult(interp), (result == TCL_OK));
+  return TCL_OK;
+}
+
 /***************************
  * End generated XOTcl commands
  ***************************/
Index: tests/parameters.xotcl
===================================================================
diff -u -r4ce2a0659cf44b3dbb7262f63fadb3333c968751 -r4a478eb598eea7cc8dec70222777d114c55f1ff8
--- tests/parameters.xotcl	(.../parameters.xotcl)	(revision 4ce2a0659cf44b3dbb7262f63fadb3333c968751)
+++ tests/parameters.xotcl	(.../parameters.xotcl)	(revision 4a478eb598eea7cc8dec70222777d114c55f1ff8)
@@ -7,6 +7,29 @@
 
 ::xotcl::use xotcl2
 
+#######################################################
+# valuecheck
+#######################################################
+Test case valuecheck
+Test parameter count 10000
+#Test parameter count 10
+Object create o1
+? {::xotcl::valuecheck object o1} 1
+? {::xotcl::is o1 object} 1
+? {::xotcl::valuecheck class o1} 0
+? {::xotcl::valuecheck class Test} 1
+? {::xotcl::valuecheck object,multivalued [list o1 Test]} 1
+? {::xotcl::valuecheck integer 1} 1
+? {::xotcl::valuecheck integer,multivalued [list 1 2 3]} 1
+? {::xotcl::valuecheck integer,multivalued [list 1 2 3 a]} 0
+? {::xotcl::valuecheck in1 aaa} {invalid value constraints "in1"}
+
+#######################################################
+# objectparameter
+#######################################################
+Test case objectparameter
+
+Test parameter count 10
 Class create C -parameter {a {b:boolean} {c 1}}
 C create c1 
 ? {C eval {:objectparameter}} "-object-mixin:relation -mixin:relation,arg=class-mixin\
@@ -18,9 +41,10 @@
     "-a -b:boolean {-c 1} -mixin:relation,arg=object-mixin -filter:relation\
 -class:relation -noinit:method,optional,noarg -volatile:method,optional,noarg\
 arg:initcmd,optional"
-#
+
+#######################################################
 # reclass to Object, no need to do anything on caching
-#
+#######################################################
 Test case reclass
 c1 class Object
 ? {c1 eval :objectparameter} "-mixin:relation,arg=object-mixin -filter:relation\
@@ -35,9 +59,9 @@
 -class:relation -noinit:method,optional,noarg -volatile:method,optional,noarg\
 arg:initcmd,optional"
 
-#
+#######################################################
 # Add mixin
-#
+#######################################################
 Test case objparam-mixins
 Class create M -parameter {m1 m2 b}
 Class create M2 -parameter {b2}
@@ -77,9 +101,9 @@
 arg:initcmd,optional"
 
 
-#
+#######################################################
 # test passed arguments
-#
+#######################################################
 Test case passed-arguments
 
 ? {catch {D create d1 -d 123}} 0 "create d1 with required argument given"
@@ -131,9 +155,9 @@
     {Parameter option 'relation' not allowed} \
     "don't allow relation option as method parameter"
 
-#
+#######################################################
 # non required positional arguments
-#
+#######################################################
 Test case non-reg-args
 
 D method foo {a b:optional c:optional} {
@@ -149,9 +173,9 @@
 ? {d1 foo 1 2} "1-1-0-1" "omit optional argument"
 ? {d1 foo 1} "1-0-0-1" "omit optional arguments"
 
-#
+#######################################################
 # non required positional arguments
-#
+#######################################################
 Test case multivalued
 Object create o
 
@@ -184,9 +208,9 @@
 ? {foo ints add 0} "0 1 2"
 ? {foo ints add a} {expected integer but got "a"}
 
-#
+#######################################################
 # subst default tests
-#
+#######################################################
 Test case subst-default
 
 D method bar {
@@ -269,9 +293,9 @@
     "a 1 b 1 c 1 end 1" \
     "query arguments with default, no paramdefs needed"
 
-#
+#######################################################
 # Query method parameter
-#
+#######################################################
 Test case query-method-parameter
 
 ? {D info method parameter foo} \
@@ -296,9 +320,9 @@
 #    "query instparams for info method 'params' method"
 
 
-#
+#######################################################
 # user defined parameter types
-#
+#######################################################
 Test case user-types
 
 #
@@ -396,9 +420,9 @@
 ? {d1 foo -a 2 10} "a=2,b=10"
 
 
-#
+#######################################################
 # testing object types in method parameters
-#
+#######################################################
 Test case mp-object-types
 Class create M
 D create d1 -d 1
@@ -481,9 +505,9 @@
     "o not of type ::C"
 
 
-#
+#######################################################
 # testing object types in object parameters
-#
+#######################################################
 Test case op-object-types
 Class create M
 D create d1 -d 1
@@ -513,12 +537,6 @@
 #       maybe "mixin" => "hasmixin"
 #       => effects as well ::xotcl::is
 #
-# TODO: It looks, as if we need multivalues as well on object
-#       parameters. If a slot has multivalued set, objectparameter
-#       must honor it. This would allow general checking of e.g.  list
-#       of integers, list of objects, etc. Therefore, we would not
-#       need to duplicate this functionality on the slots.
-#
 # TODO (optimization): optimizer can improve parameter checking:
 #       (a) simple approach: make scripted setter methods on domain
 #       (b) maybe nicer: provide arguments to c-setter to