Index: TODO
===================================================================
diff -u -r3a246dd237252e81aa7f4a37cba2affb0b9ecf00 -r58c1880b874484f218afa0275b0998e25d4282f0
--- TODO	(.../TODO)	(revision 3a246dd237252e81aa7f4a37cba2affb0b9ecf00)
+++ TODO	(.../TODO)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -2848,8 +2848,13 @@
    * changed specification of name of method from arg= to method=
    * this way "type" info in "info parameter syntax" is handled automatically
 
+- nsf.c: 
+  * added a new converter for converting mixins with guards (named mixinspec)
+  * used mixinspec in nx.tcl and xotcl2.tcl
+  * extended nx regression test.
+
+
 TODO:
-- maybe: define a type for converting mixins+guards
 - add explicit regression tests for disposition + types
 - check refcounting for dispo+types
 - maybe: add a dispoition=pipe
Index: generic/nsf.c
===================================================================
diff -u -r3a246dd237252e81aa7f4a37cba2affb0b9ecf00 -r58c1880b874484f218afa0275b0998e25d4282f0
--- generic/nsf.c	(.../nsf.c)	(revision 3a246dd237252e81aa7f4a37cba2affb0b9ecf00)
+++ generic/nsf.c	(.../nsf.c)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -5054,11 +5054,139 @@
 
 
 
+/***********************************************************************
+ * Mixin support 
+ ***********************************************************************/
+
 /*
- * Per-Object-Mixins
+ * Mixinspec type begin
  */
+typedef struct {
+  NsfClass *class;
+  Tcl_Obj *guardObj;
+} MixinSpec;
 
+static Tcl_DupInternalRepProc	MixinspecDupInteralRep;
+static Tcl_FreeInternalRepProc	MixinspecFreeInternalRep;
+static Tcl_UpdateStringProc	MixinspecUpdateString;
+static Tcl_SetFromAnyProc       MixinspecSetFromAny;
+
+static Tcl_ObjType mixinspecObjType = {
+    "nsfMixinspec",			/* name */
+    MixinspecFreeInternalRep,		/* freeIntRepProc */
+    MixinspecDupInteralRep,		/* dupIntRepProc */
+    MixinspecUpdateString,		/* updateStringProc */
+    MixinspecSetFromAny			/* setFromAnyProc */
+};
+
+/* 
+ * Dummy placeholder, should never be called.
+ */
+static void
+MixinspecUpdateString(Tcl_Obj *objPtr) {
+  Tcl_Panic("MixinspecUpdateString %s of type %s should not be called", "updateStringProc",
+	    objPtr->typePtr->name);
+}
+
+/* 
+ * Dummy placeholder, should never be called.
+ */
+static void
+MixinspecDupInteralRep(Tcl_Obj *srcPtr, Tcl_Obj *UNUSED(dupPtr)) {
+  Tcl_Panic("MixinspecDupInteralRep %s of type %s should not be called", "dupStringProc",
+	    srcPtr->typePtr->name);
+}
+
+/* 
+ * freeIntRepProc
+ */
+static void
+MixinspecFreeInternalRep(
+    register Tcl_Obj *objPtr)	/* Mixinspec structure object with internal
+				 * representation to free. */
+{
+  MixinSpec *mixinSpecPtr = (MixinSpec *)objPtr->internalRep.twoPtrValue.ptr1;
+
+  if (mixinSpecPtr != NULL) {
+    /*fprintf(stderr, "MixinspecFreeInternalRep freeing mixinSpec %p class %p guard %p\n",
+      mixinSpecPtr, mixinSpecPtr->class, mixinSpecPtr->guardObj);*/
+    /*
+     * Decrement refCounts
+     */
+    NsfObjectRefCountDecr(&(mixinSpecPtr->class)->object);
+    if (mixinSpecPtr->guardObj) {DECR_REF_COUNT(mixinSpecPtr->guardObj);}
+
+    /*
+     * ... and free structure
+     */
+    FREE(MixinSpec, mixinSpecPtr);
+  }
+}
+
+/* 
+ * setFromAnyProc
+ */
+static int
+MixinspecSetFromAny(
+    Tcl_Interp *interp,		/* Used for error reporting if not NULL. */
+    register Tcl_Obj *objPtr)	/* The object to convert. */
+{
+  NsfClass *mixin = NULL;
+  Tcl_Obj *guardObj = NULL, *nameObj;
+  int oc; Tcl_Obj **ov;
+  MixinSpec *mixinSpecPtr;
+
+  if (Tcl_ListObjGetElements(interp, objPtr, &oc, &ov) == TCL_OK) {
+    if (oc == 3 && !strcmp(ObjStr(ov[1]), NsfGlobalStrings[NSF_GUARD_OPTION])) {
+      nameObj = ov[0];
+      guardObj = ov[2];
+      /*fprintf(stderr, "mixinadd name = '%s', guard = '%s'\n", ObjStr(name), ObjStr(guard));*/
+    } else if (oc == 1) {
+      nameObj = ov[0];
+    } else {
+      return TCL_ERROR;
+    }
+  } else {
+    return TCL_ERROR;
+  }
+
+  /* we have no baseclass, we have to pass NULL as last argument */
+  if (GetClassFromObj(interp, nameObj, &mixin, NULL) != TCL_OK) {
+    return NsfObjErrType(interp, "mixin", nameObj, "a class as mixin", NULL);
+  }
+  
+  /*
+   * Conversion was ok.
+   * Allocate structure ... 
+   */
+  mixinSpecPtr = NEW(MixinSpec);
+  /*
+   * ... and increment refCounts
+   */
+  NsfObjectRefCountIncr((&mixin->object));
+  if (guardObj) {INCR_REF_COUNT(guardObj);}
+
+  mixinSpecPtr->class = mixin;
+  mixinSpecPtr->guardObj = guardObj;
+
+  /*fprintf(stderr, "MixinspecSetFromAny alloc mixinSpec %p class %p guard %p\n",
+    mixinSpecPtr, mixinSpecPtr->class, mixinSpecPtr->guardObj);*/
+
+  /*
+   * Free origninal rep and store structure as internal representation.
+   */
+  TclFreeIntRep(objPtr);
+  objPtr->internalRep.twoPtrValue.ptr1 = (void *)mixinSpecPtr;
+  objPtr->internalRep.twoPtrValue.ptr2 = NULL;
+  objPtr->typePtr = &mixinspecObjType;
+
+  return TCL_OK;
+}
 /*
+ * Mixinspec type end
+ */
+
+/*
  * push a mixin stack information on this object
  */
 static int
@@ -5104,9 +5232,10 @@
         if ((pl->cl->object.flags & NSF_IS_ROOT_CLASS) == 0) {
           NsfClassOpt *opt = pl->cl->opt;
 
-	  //fprintf(stderr, "find %p %s in checklist 1 %p\n", pl->cl, ClassName(pl->cl), *checkList);
+	  /* fprintf(stderr, "find %p %s in checklist 1 %p\n", 
+	     pl->cl, ClassName(pl->cl), *checkList);*/
 	  if (NsfClassListFind(*checkList, pl->cl)) {
-	    //fprintf(stderr, "+++ never add %s\n", ClassName(pl->cl));
+	    /*fprintf(stderr, "+++ never add %s\n", ClassName(pl->cl));*/
 	  } else {
 	    if (opt && opt->classmixins) {
 	      /* 
@@ -5127,16 +5256,26 @@
     }
   }
 
-  //NsfClassListPrint("MixinComputeOrderFullList final", *mixinClasses);
-  //NsfClassListPrint("MixinComputeOrderFullList check", *checkList);
-
   if (level == 0 && *checkList) {
     NsfClassListFree(*checkList);
     *checkList = NULL;
   }
-
 }
 
+/*
+ *----------------------------------------------------------------------
+ * MixinResetOrder --
+ *
+ *    Free the mixin order of the provided object if it exists.
+ *
+ * Results:
+ *    void
+ *
+ * Side effects:
+ *    Frees potentially the mixinOrder list.
+ *
+ *----------------------------------------------------------------------
+ */
 static void
 MixinResetOrder(NsfObject *object) {
   /*fprintf(stderr, "MixinResetOrder for object %s \n", ObjectName(object));*/
@@ -5161,7 +5300,7 @@
  */
 static void 
 NsfClassListAddPerClassMixins(Tcl_Interp *interp, NsfClass *cl, 
-			   NsfClasses **classList, NsfClasses **checkList) {
+			      NsfClasses **classList, NsfClasses **checkList) {
   NsfClasses *pl;
 
   for (pl = ComputeOrder(cl, cl->order, Super); pl; pl = pl->nextPtr) {
@@ -5279,8 +5418,21 @@
   /*CmdListPrint(interp, "mixin order\n", obj->mixinOrder);*/
 }
 
+
 /*
- * add a mixin class to 'mixinList' by appending it
+ *----------------------------------------------------------------------
+ * MixinAdd --
+ *
+ *    Add a mixinspec (mixin class with a potential guard) provided as a
+ *    Tcl_Obj* to 'mixinList' by appending it to the provided cmdList.
+ *
+ * Results:
+ *    Tcl result code.
+ *
+ * Side effects:
+ *    Potentially allocating cmd list elements added to the mixinList
+ *
+ *----------------------------------------------------------------------
  */
 static int
 MixinAdd(Tcl_Interp *interp, NsfCmdList **mixinList, Tcl_Obj *nameObj, NsfClass *baseClass) {
@@ -5289,17 +5441,32 @@
   int ocName; Tcl_Obj **ovName;
   NsfCmdList *new;
 
-  if (Tcl_ListObjGetElements(interp, nameObj, &ocName, &ovName) == TCL_OK && ocName > 1) {
-    if (ocName == 3 && !strcmp(ObjStr(ovName[1]), NsfGlobalStrings[NSF_GUARD_OPTION])) {
-      nameObj = ovName[0];
-      guardObj = ovName[2];
-      /*fprintf(stderr, "mixinadd name = '%s', guard = '%s'\n", ObjStr(name), ObjStr(guard));*/
-    } /*else return NsfPrintError(interp, "mixin registration '%s' has too many elements", 
-	ObjStr(name));*/
-  }
+  /*fprintf(stderr, "MixinAdd gets obj %p type %p %s\n", nameObj, nameObj->typePtr, 
+    nameObj->typePtr?nameObj->typePtr->name : "NULL");*/
+  /*
+   * When the provided nameObj is of type mixinspecObjType, the nsf specific
+   * converter was called already and we can simply obtain the mixin class and
+   * the guard from the internal representation.
+   */
+  if (nameObj->typePtr == &mixinspecObjType) {
+    MixinSpec *mixinSpecPtr =  nameObj->internalRep.twoPtrValue.ptr1;
+    
+    guardObj = mixinSpecPtr->guardObj;
+    mixin = mixinSpecPtr->class;
 
-  if (GetClassFromObj(interp, nameObj, &mixin, baseClass) != TCL_OK) {
-    return NsfObjErrType(interp, "mixin", nameObj, "a class as mixin", NULL);
+  } else {
+    if (Tcl_ListObjGetElements(interp, nameObj, &ocName, &ovName) == TCL_OK && ocName > 1) {
+      if (ocName == 3 && !strcmp(ObjStr(ovName[1]), NsfGlobalStrings[NSF_GUARD_OPTION])) {
+	nameObj = ovName[0];
+	guardObj = ovName[2];
+	/*fprintf(stderr, "mixinadd name = '%s', guard = '%s'\n", ObjStr(name), ObjStr(guard));*/
+      } /*else return NsfPrintError(interp, "mixin registration '%s' has too many elements", 
+	  ObjStr(name));*/
+    }
+
+    if (GetClassFromObj(interp, nameObj, &mixin, baseClass) != TCL_OK) {
+      return NsfObjErrType(interp, "mixin", nameObj, "a class as mixin", NULL);
+    }
   }
   new = CmdListAdd(mixinList, mixin->object.id, NULL, /*noDuplicates*/ 1);
 
@@ -9214,6 +9381,19 @@
 }
 
 int
+Nsf_ConvertToMixinspec(Tcl_Interp *interp, Tcl_Obj *objPtr,  Nsf_Param CONST *pPtr,
+	       ClientData *clientData, Tcl_Obj **outObjPtr) {
+  int result;
+  *outObjPtr = objPtr;
+  ///yyyyy
+  result = Tcl_ConvertToType(interp, objPtr, &mixinspecObjType);
+  if (result == TCL_OK) {
+    return result;
+  }
+  return NsfObjErrType(interp, NULL, objPtr, "mixinspec", (Nsf_Param *)pPtr);
+}
+
+int
 Nsf_ConvertToParameter(Tcl_Interp *interp, Tcl_Obj *objPtr, Nsf_Param CONST *pPtr,
 		   ClientData *clientData, Tcl_Obj **outObjPtr) {
   CONST char *value = ObjStr(objPtr);
@@ -9491,6 +9671,9 @@
     result = ParamOptionSetConverter(interp, paramPtr, "class", Nsf_ConvertToClass);
     paramPtr->flags |= NSF_ARG_BASECLASS;
 
+  } else if (strncmp(option, "mixinspec", 9) == 0) {
+    result = ParamOptionSetConverter(interp, paramPtr, "mixinspec", Nsf_ConvertToMixinspec);
+
   } else if (strncmp(option, "parameter", 9) == 0) {
     result = ParamOptionSetConverter(interp, paramPtr, "parameter", Nsf_ConvertToParameter);
 
@@ -15439,8 +15622,8 @@
     }
 
     assert(object);
-    assert(object->refCount>0);
-    assert(object->cmdName->refCount>0);
+    assert(object->refCount > 0);
+    assert(object->cmdName->refCount > 0);
     assert(object->activationCount >= 0);
 
 
@@ -17587,7 +17770,7 @@
 }
 
 static Tcl_ObjType paramObjType = {
-    "nsfParam",			/* name */
+    "nsfParam",				/* name */
     ParamFreeInternalRep,		/* freeIntRepProc */
     ParamDupInteralRep,			/* dupIntRepProc */
     ParamUpdateString,			/* updateStringProc */
Index: generic/nsfDecls.h
===================================================================
diff -u -r1b551b5aef49944bda6cb78a8a5c5d09c3e76d5a -r58c1880b874484f218afa0275b0998e25d4282f0
--- generic/nsfDecls.h	(.../nsfDecls.h)	(revision 1b551b5aef49944bda6cb78a8a5c5d09c3e76d5a)
+++ generic/nsfDecls.h	(.../nsfDecls.h)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -181,7 +181,7 @@
     struct NsfStubHooks *hooks;
 
     int (*nsf_Init) (Tcl_Interp *interp); /* 0 */
-    void *reserved1;
+    VOID *reserved1;
     struct Nsf_Class * (*nsfIsClass) (Tcl_Interp *interp, ClientData cd); /* 2 */
     struct Nsf_Object * (*nsfGetObject) (Tcl_Interp *interp, CONST char *name); /* 3 */
     struct Nsf_Class * (*nsfGetClass) (Tcl_Interp *interp, CONST char *name); /* 4 */
Index: library/nx/nx.tcl
===================================================================
diff -u -r3a246dd237252e81aa7f4a37cba2affb0b9ecf00 -r58c1880b874484f218afa0275b0998e25d4282f0
--- library/nx/nx.tcl	(.../nx.tcl)	(revision 3a246dd237252e81aa7f4a37cba2affb0b9ecf00)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -1216,12 +1216,12 @@
     ${os}::Class::slot::dummy destroy
 
     ::nx::RelationSlot create ${os}::Object::slot::mixin \
-	-forwardername object-mixin -elementtype class
+	-forwardername object-mixin -elementtype mixinspec
     ::nx::RelationSlot create ${os}::Object::slot::filter \
 	-forwardername object-filter
 
     ::nx::RelationSlot create ${os}::Class::slot::mixin \
-	-forwardername class-mixin -elementtype class
+	-forwardername class-mixin -elementtype mixinspec
     ::nx::RelationSlot create ${os}::Class::slot::filter \
         -forwardername class-filter
 
@@ -1230,7 +1230,7 @@
     # of per-object mixins and filters for classes.
     #
     ::nx::ObjectParameterSlot create ${os}::Class::slot::object-mixin \
-	-methodname "::nsf::classes::nx::Object::mixin" -elementtype class
+	-methodname "::nsf::classes::nx::Object::mixin" -elementtype mixinspec
     ::nx::ObjectParameterSlot create ${os}::Class::slot::object-filter \
 	-methodname "::nsf::classes::nx::Object::filter"
 
Index: library/xotcl/library/xotcl2.tcl
===================================================================
diff -u -r3a246dd237252e81aa7f4a37cba2affb0b9ecf00 -r58c1880b874484f218afa0275b0998e25d4282f0
--- library/xotcl/library/xotcl2.tcl	(.../xotcl2.tcl)	(revision 3a246dd237252e81aa7f4a37cba2affb0b9ecf00)
+++ library/xotcl/library/xotcl2.tcl	(.../xotcl2.tcl)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -403,11 +403,11 @@
     ::nx::RelationSlot create ${oSlotContainer}::class -elementtype class -multiplicity 1..1
     ::nsf::method::alias      ${oSlotContainer}::class assign ::nsf::relation
     ::nx::RelationSlot create ${oSlotContainer}::mixin  -forwardername object-mixin \
-	-elementtype mixin -multiplicity 0..n
+	-elementtype mixinspec -multiplicity 0..n
     ::nx::RelationSlot create ${oSlotContainer}::filter -forwardername object-filter \
 	-multiplicity 0..n
     ::nx::RelationSlot create ${cSlotContainer}::instmixin  -forwardername class-mixin \
-	-elementtype mixin -multiplicity 0..n
+	-elementtype mixinspec -multiplicity 0..n
     ::nx::RelationSlot create ${cSlotContainer}::instfilter -forwardername class-filter \
 	-multiplicity 0..n
   }
Index: library/xotcl/tests/slottest.xotcl
===================================================================
diff -u -r3a246dd237252e81aa7f4a37cba2affb0b9ecf00 -r58c1880b874484f218afa0275b0998e25d4282f0
--- library/xotcl/tests/slottest.xotcl	(.../slottest.xotcl)	(revision 3a246dd237252e81aa7f4a37cba2affb0b9ecf00)
+++ library/xotcl/tests/slottest.xotcl	(.../slottest.xotcl)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -112,7 +112,7 @@
 ? {o1 class} "::O"
 o1 class Object
 ? {o1 class} "::xotcl::Object"
-? {Object objectparameter} "-mixin:alias,0..n -filter:alias,0..n -class:class,alias args"
+? {Object objectparameter} "-mixin:mixinspec,alias,0..n -filter:alias,0..n -class:class,alias args"
 ? {o1 class add M} {class: expected a class but got "M ::xotcl::Object"}
 
 
Index: library/xotcl/tests/testx.xotcl
===================================================================
diff -u -r1915597e6ad2a44c3f33b80e7f530920db2a6001 -r58c1880b874484f218afa0275b0998e25d4282f0
--- library/xotcl/tests/testx.xotcl	(.../testx.xotcl)	(revision 1915597e6ad2a44c3f33b80e7f530920db2a6001)
+++ library/xotcl/tests/testx.xotcl	(.../testx.xotcl)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -772,8 +772,8 @@
       B instproc f1 args {next}
       B instproc f2 args {next}
       B b
-      B instfilter {{f1  -guard {[self] eq "::b"}} {f2  -guard 0} f1}
-      b filter {{f1  -guard {[self] eq "::b"}} {f2  -guard 0}}
+      B instfilter {{f1 -guard {[self] eq "::b"}} {f2 -guard 0} f1}
+      b filter {{f1 -guard {[self] eq "::b"}} {f2 -guard 0}}
 
       ::errorCheck [B info instfilter] {f1 f2} "info filter order a"
       ::errorCheck [B info instfilter -guards] {f1 {f2 -guard 0}} "info filter order b"
Index: tests/info-method.test
===================================================================
diff -u -r3a246dd237252e81aa7f4a37cba2affb0b9ecf00 -r58c1880b874484f218afa0275b0998e25d4282f0
--- tests/info-method.test	(.../info-method.test)	(revision 3a246dd237252e81aa7f4a37cba2affb0b9ecf00)
+++ tests/info-method.test	(.../info-method.test)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -493,10 +493,10 @@
     :method "sub foo" args {;}
   }
 
-  ? {C info parameter syntax} "?-a value? ?-b value? ?-volatile? ?-noinit? ?-mixin class ...? ?-class class? ?-filter value ...? ?__initcmd?"
+  ? {C info parameter syntax} "?-a value? ?-b value? ?-volatile? ?-noinit? ?-mixin mixinspec ...? ?-class class? ?-filter value ...? ?__initcmd?"
   ? {C info parameter syntax a} "?-a value?"
 
-  ? {C info parameter spec} "-a {-b 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
+  ? {C info parameter spec} "-a {-b 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
 
   ? {C info parameter list} "-a -b -volatile -noinit -mixin -class -filter __initcmd"
   ? {C info parameter name} "a b volatile noinit mixin class filter __initcmd"
Index: tests/parameters.test
===================================================================
diff -u -r3a246dd237252e81aa7f4a37cba2affb0b9ecf00 -r58c1880b874484f218afa0275b0998e25d4282f0
--- tests/parameters.test	(.../parameters.test)	(revision 3a246dd237252e81aa7f4a37cba2affb0b9ecf00)
+++ tests/parameters.test	(.../parameters.test)	(revision 58c1880b874484f218afa0275b0998e25d4282f0)
@@ -249,7 +249,7 @@
   C create c1
  
   ? {C eval :objectparameter} \
-      "-a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
+      "-a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
 
   ? {c1 eval :objectparameter} \
       "::c1: unable to dispatch method 'objectparameter'"
@@ -276,7 +276,7 @@
       "::D::slot::d ::C::slot::a ::C::slot::b ::C::slot::c"
   
   ? {D eval :objectparameter} \
-      "-d:required -a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
+      "-d:required -a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
 }
 
 #######################################################
@@ -293,29 +293,29 @@
   D mixin M
 
   ? {D eval :objectparameter} \
-      "-b -m1 -m2 -d:required -a {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" \
+      "-b -m1 -m2 -d:required -a {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" \
     "mixin added"
 
   M mixin M2
 
   ? {D eval :objectparameter} \
-      "-b2 -b -m1 -m2 -d:required -a {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" \
+      "-b2 -b -m1 -m2 -d:required -a {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" \
     "transitive mixin added"
   D mixin ""
   #we should have again the old interface
 
   ? {D eval :objectparameter} \
-      "-d:required -a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
+      "-d:required -a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
 
   C mixin M
   ? {D eval :objectparameter} \
-      "-b2 -b -m1 -m2 -d:required -a {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" \
+      "-b2 -b -m1 -m2 -d:required -a {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" \
     "mixin added"
   C mixin ""
   #we should have again the old interface
   
   ? {D eval :objectparameter} \
-      "-d:required -a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" 
+      "-d:required -a -b:boolean {-c 1} -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional" 
 }
 
 #######################################################
@@ -688,10 +688,33 @@
   Class create D -superclass C -attributes d
 
   Class create M
+  Class create M2
   D create d1 -d 1
   C create c1 -mixin M
+  C create c2 -mixin {{M -guard true}}
+  C create c3 -mixin {M ::M2}
+  C create c4 -mixin {{M -guard 1} M2}
+  C create c5 -mixin {M {M2 -guard 2}}
   Object create o
-  
+
+  ? {c1 info mixin classes} ::M
+  ? {c1 info mixin guard ::M} ""
+
+  ? {c2 info mixin classes} ::M
+  ? {c2 info mixin guard ::M} "true"
+
+  ? {c3 info mixin classes} {::M ::M2}
+  ? {c3 info mixin guard M} ""
+  ? {c3 info mixin guard M2} ""
+
+  ? {c4 info mixin classes} {::M ::M2}
+  ? {c4 info mixin guard M} "1"
+  ? {c4 info mixin guard M2} ""
+
+  ? {c5 info mixin classes} {::M ::M2}
+  ? {c5 info mixin guard M} ""
+  ? {c5 info mixin guard M2} "2"
+
   D public method foo-base     {x:baseclass} {return $x}
   D public method foo-class    {x:class} {return $x}
   D public method foo-object   {x:object} {return $x}
@@ -1596,7 +1619,7 @@
 
   ? {C info slots -closure} "::C::slot::a1 ::nx::Object::slot::volatile ::nx::Object::slot::noinit ::nx::Object::slot::mixin ::nx::Object::slot::__initcmd ::nx::Object::slot::class ::nx::Object::slot::filter"
 
-  ? {C eval :objectparameter} "-a1 -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
+  ? {C eval :objectparameter} "-a1 -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
 
   #
   # invalidate object parameter and expect that the per-class mixin
@@ -1610,7 +1633,7 @@
 
   ? {C info slots -closure} "::C::slot::a1 ::nx::Object::slot::volatile ::nx::Object::slot::noinit ::nx::Object::slot::mixin ::nx::Object::slot::__initcmd ::nx::Object::slot::class ::nx::Object::slot::filter"
 
-  ? {C eval :objectparameter} "-a1 -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:class,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
+  ? {C eval :objectparameter} "-a1 -volatile:alias,noarg -noinit:alias,method=::nsf::methods::object::noinit,noarg -mixin:mixinspec,alias,1..n -class:class,alias,method=::nsf::methods::object::class -filter:alias,1..n __initcmd:initcmd,optional"
 
   # should not require b1
   ? {C create c2} ::c2