Index: TODO
===================================================================
diff -u -r511fca2017ee0cabbfef93bfb482cd165def8190 -r96716c484bb18d390fef1eecdca764b56121dc4d
--- TODO	(.../TODO)	(revision 511fca2017ee0cabbfef93bfb482cd165def8190)
+++ TODO	(.../TODO)	(revision 96716c484bb18d390fef1eecdca764b56121dc4d)
@@ -1889,6 +1889,14 @@
 - extended regression test with testcases for creation of parent 
   objects via method "__unknown"
 
+- disallow object parameter of type "switch" to avoid possible
+  confusion between (a) providing a value for the o.p., (b) calling
+  it as a setter, and (c) calling it as a getter. For providing a
+  value, no arg is used for switch. For calling a setter, it is 
+  necessary to provide a value even for a switch.
+- disallow type "switch" in setter definiton (use boolean instead)
+- disallow type "switch" for positional arguments (use boolean instead)
+- extended regression test
 
 TODO:
 
Index: generic/nsf.c
===================================================================
diff -u -rbf14514386be7b9b2b97e3790ea9ec78c8e11b22 -r96716c484bb18d390fef1eecdca764b56121dc4d
--- generic/nsf.c	(.../nsf.c)	(revision bf14514386be7b9b2b97e3790ea9ec78c8e11b22)
+++ generic/nsf.c	(.../nsf.c)	(revision 96716c484bb18d390fef1eecdca764b56121dc4d)
@@ -474,7 +474,7 @@
  *  NsfObject Reference Accounting
  */
 #if defined(NSFOBJ_TRACE)
-# define NsfObjectRefCountIncr(obj)                                   \
+# define NsfObjectRefCountIncr(obj)					\
   (obj)->refCount++;                                                    \
   fprintf(stderr, "RefCountIncr %p count=%d %s\n", obj, obj->refCount, obj->cmdName?ObjStr(obj->cmdName):"no name"); \
   MEM_COUNT_ALLOC("NsfObject RefCount", obj)
@@ -8098,6 +8098,13 @@
     paramPtr->converterArg =  Tcl_NewStringObj(option+4, length-4);
     INCR_REF_COUNT(paramPtr->converterArg);
   } else if (strncmp(option, "switch", 6) == 0) {
+    fprintf(stderr, "switch name %s\n", paramPtr->name);
+    if (*paramPtr->name != '-') {
+      return NsfVarErrMsg(interp,
+			  "invalid parameter type \"switch\" for argument ", paramPtr->name,
+                            "; type \"switch\" only allowed for non-positional arguments",
+                            (char *) NULL);
+    }
     result = ParamOptionSetConverter(interp, paramPtr, "switch", ConvertToSwitch);
     paramPtr->flags |= NSF_ARG_SWITCH;
     paramPtr->nrArgs = 0;
Index: generic/nsfInt.h
===================================================================
diff -u -r511fca2017ee0cabbfef93bfb482cd165def8190 -r96716c484bb18d390fef1eecdca764b56121dc4d
--- generic/nsfInt.h	(.../nsfInt.h)	(revision 511fca2017ee0cabbfef93bfb482cd165def8190)
+++ generic/nsfInt.h	(.../nsfInt.h)	(revision 96716c484bb18d390fef1eecdca764b56121dc4d)
@@ -373,8 +373,8 @@
 
 /* Disallowed parameter options */
 #define NSF_DISALLOWED_ARG_METHOD_PARAMETER	     (NSF_ARG_METHOD|NSF_ARG_INITCMD|NSF_ARG_RELATION)
-#define NSF_DISALLOWED_ARG_SETTER	     	     (NSF_ARG_SUBST_DEFAULT|NSF_DISALLOWED_ARG_METHOD_PARAMETER)
-#define NSF_DISALLOWED_ARG_OBJECT_PARAMETER	     0
+#define NSF_DISALLOWED_ARG_SETTER	     	     (NSF_ARG_SWITCH|NSF_ARG_SUBST_DEFAULT|NSF_DISALLOWED_ARG_METHOD_PARAMETER)
+#define NSF_DISALLOWED_ARG_OBJECT_PARAMETER	     (NSF_ARG_SWITCH)
 #define NSF_DISALLOWED_ARG_VALUECHECK	     (NSF_ARG_SUBST_DEFAULT|NSF_ARG_METHOD|NSF_ARG_INITCMD|NSF_ARG_RELATION|NSF_ARG_SWITCH|NSF_ARG_CURRENTLY_UNKNOWN)
 
 
Index: library/nx/nx.tcl
===================================================================
diff -u -r5fa3584b0f682d4103c39af82357713871f1de0c -r96716c484bb18d390fef1eecdca764b56121dc4d
--- library/nx/nx.tcl	(.../nx.tcl)	(revision 5fa3584b0f682d4103c39af82357713871f1de0c)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision 96716c484bb18d390fef1eecdca764b56121dc4d)
@@ -614,7 +614,9 @@
         }
       }
     }
+
     if {[info exists type]} {
+      if {$type eq "switch"} {error "switch is not allowed as type for object parameter $name"}
       lappend opts -type $type
     }
 
@@ -801,6 +803,7 @@
     set objopts [list]
     set methodopts [list]
     set type ""
+
     if {[info exists :required] && ${:required}} {
       lappend objopts required
       lappend methodopts required
Index: tests/parameters.test
===================================================================
diff -u -r277704be44e8205d6aa0507c840e44223039f841 -r96716c484bb18d390fef1eecdca764b56121dc4d
--- tests/parameters.test	(.../parameters.test)	(revision 277704be44e8205d6aa0507c840e44223039f841)
+++ tests/parameters.test	(.../parameters.test)	(revision 96716c484bb18d390fef1eecdca764b56121dc4d)
@@ -195,7 +195,7 @@
 #  relation           NO         YES        NO    NO      YES     NO          NO          YES
 #  stringtype         YES        YES        NO    NO      NO      YES         YES         YES
 #
-#  switch             NO         NO         NO    NO      NO      NO          YES         YES
+#  switch             NO         NO         NO    NO      NO      NO          YES         NO
 #  integer            YES        YES        NO    NO      NO      YES         YES         YES    
 #  boolean            YES        YES        NO    NO      NO      YES         YES         YES
 #  object             YES        YES        NO    YES     NO      YES         YES         YES
@@ -477,19 +477,21 @@
     {literal "\\[current\\]"} 
     {c "[:info class]"} 
     {d "literal $d"}
-    {switch:switch}
   }
+
+  ? {Bar attribute ss:switch} "switch is not allowed as type for object parameter ss"
+
   Bar create bar1
   #puts stderr [bar1 objectparameter]
   
-  ? {subst {[bar1 s]-[bar1 literal]-[bar1 c]-[bar1 d]-[bar1 switch]}} \
-      {::bar1-[current]-::Bar-literal $d-0} \
-      "substdefault and switch in object parameter 1"
+  ? {subst {[bar1 s]-[bar1 literal]-[bar1 c]-[bar1 d]}} \
+      {::bar1-[current]-::Bar-literal $d} \
+      "substdefault in object parameter 1"
   
-  Bar create bar2 -switch
-  ? {subst {[bar2 s]-[bar2 literal]-[bar2 c]-[bar2 d]-[bar2 switch]}} \
-      {::bar2-[current]-::Bar-literal $d-1} \
-      "substdefault and switch in object parameter 2"
+  Bar create bar2
+  ? {subst {[bar2 s]-[bar2 literal]-[bar2 c]-[bar2 d]}} \
+      {::bar2-[current]-::Bar-literal $d} \
+      "substdefault in object parameter 2"
   
   # Observations:
   #  1) syntax for "-attributes" and method parameter is quite different.
@@ -506,7 +508,7 @@
   #  2) substdefault for '$' in -attributes defaults does not make much sense.
   #     deactivated for now; otherwise we would need "\\"
   
-  D method bar {
+  D public method bar {
 		{-s:substdefault "[current]"} 
 		{-literal "[current]"} 
 		{-c:substdefault "[my c]"} 
@@ -525,6 +527,10 @@
       {{-s:substdefault "[current]"} {-literal "[current]"} {-c:substdefault "[my c]"} {-d:integer,substdefault "$d"} -switch:switch -optflag x y:integer {z 1}} \
       "query method parameter" 
   
+
+  ? {D public method foo {s:switch} {return 1}} \
+      {invalid parameter type "switch" for argument s; type "switch" only allowed for non-positional arguments}
+
   D public method foo {a b {-c 1} {-d} x {-end 100}} {
     set result [list]
     foreach v [[current class] info method args [current method]] {