Index: Makefile.in
===================================================================
diff -u -r99fb4ec76728ea1c8a432d9b7d402f3cb865e92e -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- Makefile.in	(.../Makefile.in)	(revision 99fb4ec76728ea1c8a432d9b7d402f3cb865e92e)
+++ Makefile.in	(.../Makefile.in)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -474,6 +474,7 @@
 	$(TCLSH) $(src_test_dir_native)/object-system.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/destroy.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/methods.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
+	$(TCLSH) $(src_test_dir_native)/method-parameter.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/var-access.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/varresolution.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
 	$(TCLSH) $(src_test_dir_native)/info-method.test -libdir $(PLATFORM_DIR) $(TESTFLAGS)
Index: TODO
===================================================================
diff -u -r2ba521e3dfbb1294908b51ed8e13dab5adc3ca03 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- TODO	(.../TODO)	(revision 2ba521e3dfbb1294908b51ed8e13dab5adc3ca03)
+++ TODO	(.../TODO)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -3555,10 +3555,22 @@
     for methods with primitive bodies: 5%-25%.
   - added regression tests for argument parsing 
 
+- nsf.c
+  - added experimental parameter option noleadingdash
+  - additionalal regression test file method-parameter.test
+  - provide selective error messages for unknown nonpos args
+
 TODO:
+ - NsfUnexpectedNonposArgumentError() for valueInArgument, when structure settles
+ - ouput of noleadingdash in introspection
+ - ouput of noleadingdash in objectParameterSlots
+ - handling of noleadingdash vor values of nonpos args
+ - special handling of values looking like nonpos-flags,
+   but wich are not ones (-1, "- a b c", ....) in detection
+   when to throw unknow.
+
  - check flag reuses in ~/scripts/nonposargs-speed.xotcl
  - NSF_WITH_OS_RESOLVER
- - ParseContextExtendObjv
  - private: 
    * document private in tutorial
  - add "property" and "attribute" and "info property" and "info slot ..." to migration guide
Index: generic/nsf.c
===================================================================
diff -u -re639a46f30e0e0c10dc84c898e828b9abe9298d9 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- generic/nsf.c	(.../nsf.c)	(revision e639a46f30e0e0c10dc84c898e828b9abe9298d9)
+++ generic/nsf.c	(.../nsf.c)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -10870,6 +10870,9 @@
     paramPtr->flags |= NSF_ARG_NOARG;
     paramPtr->nrArgs = 0;
 
+  } else if (strncmp(option, "noleadingdash", 8) == 0) {
+    paramPtr->flags |= NSF_ARG_NOLEADINGDASH;
+
   } else if (strncmp(option, "noconfig", 8) == 0) {
     if (disallowedOptions != NSF_DISALLOWED_ARG_OBJECT_PARAMETER) {
       return NsfPrintError(interp, "Parameter option 'noconfig' only allowed for object parameters");
@@ -15682,6 +15685,12 @@
 #define SkipNonposParamDefs(cPtr) \
   for (; ++cPtr <= lastParamPtr && *cPtr->name == '-';)
 
+Nsf_Param CONST *
+NextParam(Nsf_Param CONST *paramPtr, Nsf_Param CONST *lastParamPtr) {
+  for (; ++paramPtr <= lastParamPtr && *paramPtr->name == '-'; );
+  return paramPtr;
+}
+
 static int
 ArgumentParse(Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv[],
               NsfObject *object, Tcl_Obj *procNameObj,
@@ -15838,6 +15847,7 @@
 	    int found = 0;
 
 	    for (; pPtr <= lastParamPtr && *pPtr->name == '-'; pPtr ++) {
+	      /*fprintf(stderr, "comparing '%s' with '%s'\n", argumentString, pPtr->name);*/
 	      if ((pPtr->flags & NSF_ARG_NOCONFIG) == 0 
 		  && ch1 == pPtr->name[1]
 		  && strcmp(argumentString, pPtr->name) == 0) {
@@ -15848,8 +15858,20 @@
 	      }
 	    }
 	    if (!found) {
-	      SkipNonposParamDefs(currentParamPtr);
-	      pPtr = currentParamPtr;
+	      Nsf_Param CONST *nextParamPtr = NextParam(currentParamPtr, lastParamPtr);
+	      /*fprintf(stderr, "non-pos-arg '%s' not found, current %p %s last %p %s next %p %s\n",
+		      argumentString, 
+		      currentParamPtr,  currentParamPtr->name,
+		      lastParamPtr, lastParamPtr->name,
+		      nextParamPtr, nextParamPtr->name);*/
+	      if (nextParamPtr > lastParamPtr 
+		  || (nextParamPtr->flags & NSF_ARG_NOLEADINGDASH)) {
+		return NsfUnexpectedNonposArgumentError(interp, argumentString, 
+							(Nsf_Object *)object, 
+							currentParamPtr, paramPtr, 
+							procNameObj);
+	      }
+	      pPtr = currentParamPtr = nextParamPtr;
 	    }
 	  }
 	}
@@ -15885,7 +15907,7 @@
 	o++;
 	if (unlikely(o >= objc)) {
 	  /* we expect an argument, but we are already at the end of the argument list */
-	  return NsfPrintError(interp, "Argument for parameter '%s' expected", pPtr->name);
+	  return NsfPrintError(interp, "Value for parameter '%s' expected", pPtr->name);
 	}
 	assert(valueObj == NULL);
 	valueObj = objv[o];
Index: generic/nsf.h
===================================================================
diff -u -r2ba521e3dfbb1294908b51ed8e13dab5adc3ca03 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- generic/nsf.h	(.../nsf.h)	(revision 2ba521e3dfbb1294908b51ed8e13dab5adc3ca03)
+++ generic/nsf.h	(.../nsf.h)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -277,7 +277,15 @@
 
 extern int
 NsfUnexpectedArgumentError(Tcl_Interp *interp, CONST char *argumentString, 
-			   Nsf_Object *object, Nsf_Param CONST *paramPtr, Tcl_Obj *procNameObj);
+			   Nsf_Object *object, Nsf_Param CONST *paramPtr, 
+			   Tcl_Obj *procNameObj);
+extern int
+NsfUnexpectedNonposArgumentError(Tcl_Interp *interp, 
+				 CONST char *argumentString, 
+				 Nsf_Object *object, 
+				 Nsf_Param CONST *currentParamPtr,
+				 Nsf_Param CONST *paramPtr,
+				 Tcl_Obj *procNameObj);
 
 /*
  * logging
Index: generic/nsfError.c
===================================================================
diff -u -r2ba521e3dfbb1294908b51ed8e13dab5adc3ca03 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- generic/nsfError.c	(.../nsfError.c)	(revision 2ba521e3dfbb1294908b51ed8e13dab5adc3ca03)
+++ generic/nsfError.c	(.../nsfError.c)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -222,7 +222,8 @@
  *
  * NsfUnexpectedArgumentError --
  *
- *      Produce a unexpecte argument number (most likely, too many arguments)
+ *      Produce an error message about an unexpected argument (most likely,
+ *      too many arguments)
  *
  * Results:
  *      TCL_ERROR
@@ -250,6 +251,49 @@
 /*
  *----------------------------------------------------------------------
  *
+ * NsfUnexpectedNonposArgumentError --
+ *
+ *      Produce a unexpecte argument number (most likely, too many arguments)
+ *
+ * Results:
+ *      TCL_ERROR
+ *
+ * Side effects:
+ *      Sets the result message.
+ *
+ *----------------------------------------------------------------------
+ */
+extern int
+NsfUnexpectedNonposArgumentError(Tcl_Interp *interp, 
+				 CONST char *argumentString, 
+				 Nsf_Object *object, 
+				 Nsf_Param CONST *currentParamPtr,
+				 Nsf_Param CONST *paramPtr,
+				 Tcl_Obj *procNameObj) {
+  Tcl_DString ds, *dsPtr = &ds;
+  Nsf_Param CONST *pPtr;
+
+  DSTRING_INIT(dsPtr);
+  Tcl_DStringAppend(dsPtr, "Invalid non-positional argument '", -1);
+  Tcl_DStringAppend(dsPtr, argumentString, -1);
+  Tcl_DStringAppend(dsPtr, "', valid are : ", -1);
+  for (pPtr = currentParamPtr; pPtr->name && *pPtr->name == '-'; pPtr ++) {
+    Tcl_DStringAppend(dsPtr, pPtr->name, -1);
+    Tcl_DStringAppend(dsPtr, ", ", -1);
+  }
+  Tcl_DStringTrunc(dsPtr, Tcl_DStringLength(dsPtr) - 2);
+  Tcl_DStringAppend(dsPtr, ";\n", 2);
+  
+  NsfArgumentError(interp, Tcl_DStringValue(dsPtr), paramPtr,
+		   object ? object->cmdName : NULL,
+		   procNameObj);
+  DSTRING_FREE(dsPtr);
+  return TCL_ERROR;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * NsfDispatchClientDataError --
  *
  *      Produce a error message when method was not dispatched on an object
Index: generic/nsfInt.h
===================================================================
diff -u -r2ba521e3dfbb1294908b51ed8e13dab5adc3ca03 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- generic/nsfInt.h	(.../nsfInt.h)	(revision 2ba521e3dfbb1294908b51ed8e13dab5adc3ca03)
+++ generic/nsfInt.h	(.../nsfInt.h)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -406,6 +406,7 @@
 #define NSF_ARG_WARN			0x040000
 #define NSF_ARG_UNNAMED			0x080000
 #define NSF_ARG_IS_RETURNVALUE		0x100000
+#define NSF_ARG_NOLEADINGDASH		0x200000
 
 /* method invocations */
 #define NSF_ARG_METHOD_INVOCATION	     (NSF_ARG_ALIAS|NSF_ARG_FORWARD|NSF_ARG_INITCMD)
Index: library/xotcl/tests/slottest.xotcl
===================================================================
diff -u -ra24e1f836c3126d0a0e9467bde3a9fa8da901711 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- library/xotcl/tests/slottest.xotcl	(.../slottest.xotcl)	(revision a24e1f836c3126d0a0e9467bde3a9fa8da901711)
+++ library/xotcl/tests/slottest.xotcl	(.../slottest.xotcl)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -375,7 +375,7 @@
   C instproc init args {set ::_ $args}
 
   set ::_ ""
-  ? {C create c2 -y 1 -x} {Argument for parameter '-x' expected}
+  ? {C create c2 -y 1 -x} {Value for parameter '-x' expected}
   ? {set ::_} ""
   ? {c2 x} {can't read "x": no such variable}
   ? {C create c3 -y 1 -x 0} "::c3"
Index: library/xotcl/tests/testx.xotcl
===================================================================
diff -u -rb37bf2deab94b6294509fa79bb7b922d6e8a5635 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- library/xotcl/tests/testx.xotcl	(.../testx.xotcl)	(revision b37bf2deab94b6294509fa79bb7b922d6e8a5635)
+++ library/xotcl/tests/testx.xotcl	(.../testx.xotcl)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -4113,7 +4113,7 @@
   o foo
   o foo -foo 0
   catch {o foo -foo} msg
-  errorCheck $msg "Argument for parameter '-foo' expected" "Empty non-pos arg"
+  errorCheck $msg "Value for parameter '-foo' expected" "Empty non-pos arg"
   
   Object oa
   oa proc foo {{-a A} b} {
Index: tests/disposition.test
===================================================================
diff -u -rce55b9f6e80b8444dd248b1e6e36217716331ee9 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- tests/disposition.test	(.../disposition.test)	(revision ce55b9f6e80b8444dd248b1e6e36217716331ee9)
+++ tests/disposition.test	(.../disposition.test)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -193,9 +193,10 @@
 
   C setObjectParams {{-single-np:alias}}
   ? {[C new -single-np [list -x]] eval {set :single-np}} \
-      "Argument for parameter '-x' expected"
+      "Value for parameter '-x' expected"
   ? {[C new -single-np [list -x X]] eval {set :single-np}} \
-      "Invalid argument '-x X', maybe too many arguments; should be \"[C inst] single-np -x\""
+      "Invalid non-positional argument '-x X', valid are : -x;
+ should be \"::__%&singleton single-np -x\""
 
   #
   # INTERACTIONS with other parameter types
Index: tests/method-parameter.test
===================================================================
diff -u
--- tests/method-parameter.test	(revision 0)
+++ tests/method-parameter.test	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -0,0 +1,76 @@
+# -*- Tcl -*-
+package require nx
+package require nx::test
+
+nx::Test case method-params-0 {
+  nsf::proc p0 {} {return 1}
+  nsf::proc p1 {-x} {return [list [info exists x]]}
+
+  ? {p0} 1
+  ;# the following error msg comes from Tcl
+  ? {p0 -x} {wrong # args: should be "p0"}
+
+  ? {p1} 0
+  ? {p1 -x} {Value for parameter '-x' expected}
+  ? {p1 -x 1} 1
+  ? {p1 -x 1 2} {Invalid argument '2', maybe too many arguments; should be "p1 ?-x value?"}
+  ? {p1 -x 1 -y} {Invalid non-positional argument '-y', valid are : -x;
+ should be "p1 ?-x value?"}
+  ? {p1 a} {Invalid argument 'a', maybe too many arguments; should be "p1 ?-x value?"}
+  ? {p1 a -x} {Invalid argument 'a', maybe too many arguments; should be "p1 ?-x value?"}
+
+  ? {p1 --} 0
+  ? {p1 -y} {Invalid non-positional argument '-y', valid are : -x;
+ should be "p1 ?-x value?"}
+  ? {p1 -y --} {Invalid non-positional argument '-y', valid are : -x;
+ should be "p1 ?-x value?"}
+}
+
+nx::Test case noleadingdash {
+
+  nsf::proc p2a {-x args} {return [list [info exists x] $args]}
+  nsf::proc p2b {-x args:noleadingdash} {return [list [info exists x] $args]}
+  nsf::proc p2c {-x:noleadingdash args:noleadingdash} {return [list [info exists x] $args]}
+
+  ? {p2a -x -y} {1 {}} ;# "-y" is the value of "x"
+  ? {p2b -x -y} {1 {}} ;# "-y" is the value of "x"
+  ? {p2c -x -y} {1 {}} ;# "-y" is the value of "x"; TODO: noleadindash currently only for posargs
+
+  ? {p2a -x 1 -y} {1 -y}
+  ? {p2b -x 1 -y} {Invalid non-positional argument '-y', valid are : -x;
+ should be "p2b ?-x value? ?arg ...?"}
+  ? {p2c -x 1 -y} {Invalid non-positional argument '-y', valid are : -x;
+ should be "p2c ?-x value? ?arg ...?"}
+
+  nsf::proc p3a {a -x -y b:noleadingdash -z} {return [list $a [info exists x] [info exists y] $b]}
+
+  ? {p3a 100 -x 1 -y 1 200} {100 1 1 200}
+  ? {p3a 100 -xx 1 -y 1 200} {Invalid non-positional argument '-xx', valid are : -x, -y;
+ should be "p3a a ?-x value? ?-y value? b ?-z value?"}  
+
+
+  #
+  # For the "unknown args problem: It would be staightforward to
+  # provide an nsf-proc somewhat similar to NsfArgumentError () which
+  # gets the object passed if applicable (methodParameter)
+  #
+  # nsf::proc argumentError {cause arg -expected -msg -cmd -object -methodName} {
+  #
+  # }
+  #
+  # pros:
+  # - we could build the syntax from tcl... 
+  # - an unknown handler for nonpos args could fit in, for method and object parameters
+  # - it should be possible to switch to a raw mode to make life easier when error 
+  #   messages change.
+  # - it should be feasible to output message to tk.
+  # - one could even think about nationalizing, etc...
+  # - maybe we could fit even the unknown object handling in (::nsf::object::unknown)
+  #
+  # contras:
+  # - not sure, we can hide the context on the error stack
+  # - not exactly the tcl-way
+  # - most errors are thrown in hopeless situations (not enough args),
+  #   some errors could recover (e.g. unknown handler). we have to
+  #   signal these situations from the C code.
+}
Index: tests/object-system.test
===================================================================
diff -u -rc29a6f1e7448196346d3174a7f0a4cd18d65691a -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- tests/object-system.test	(.../object-system.test)	(revision c29a6f1e7448196346d3174a7f0a4cd18d65691a)
+++ tests/object-system.test	(.../object-system.test)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -63,13 +63,15 @@
 ? {p4 -- -x 1 2} {0 {-x 1 2}}
 ? {p4 --} {0 {}}
 ? {p4 -- --} {0 --}
+? {p4 -y --} {0 {-y --}} ;# no -y parameter, so pushed into args
 
 ? {p5} {0 0 0 {}}
 ? {p5 -x 1} {1 0 0 {}}
 ? {p5 a} {0 0 1 {}}
-? {p5 -y 1} {0 0 1 1}  ;# "-y" is passed into arg, "1" into args
+? {p5 -y 1} {0 0 1 1}        ;# "-y" is passed into arg, "1" into args
 ? {p5 -y 1 2} {0 0 1 {1 2}}  ;# "-y" is passed into arg, "1 2" into args
-? {p5 -x 1 2} {1 0 1 {}}  ;# "2" is passed into arg, "1 2" into args
+? {p5 -x 1 2} {1 0 1 {}}     ;# "2" is passed into arg, "1 2" into args
+? {p5 -y --} {0 0 1 {}}      ;# "--" is value of "y"
 
 #
 # Create objects and test its properties
Index: tests/parameters.test
===================================================================
diff -u -rb9638e7510abc38eed801d5e8f357f6f89664d90 -r24724ebae83af4e0104b349a2fb582bfc71a7475
--- tests/parameters.test	(.../parameters.test)	(revision b9638e7510abc38eed801d5e8f357f6f89664d90)
+++ tests/parameters.test	(.../parameters.test)	(revision 24724ebae83af4e0104b349a2fb582bfc71a7475)
@@ -1489,7 +1489,7 @@
   }
 
   set ::_ ""
-  ? {C create c2 -y 1 -x} {Argument for parameter '-x' expected}
+  ? {C create c2 -y 1 -x} {Value for parameter '-x' expected}
   ? {set ::_} ""
   ? {c2 x} {can't read "x": no such variable}
   ? {C create c3 -y 1 -x 0} "::c3"