The Tcl_Obj patch discussed on the patches list.

This was originally submitted by Martin von Loewis as part of his
Unicode patch; all I did was add special cases for Python int and
float objects and rearrange the object type tests somewhat to speed up
the common cases (string, int, float, tuple, unicode, object).

Modules/_tkinter.c

@@ -425,6 +425,47 @@ Split(list)
 	return v;
 }
 
+static Tcl_Obj*
+AsObj(value)
+	PyObject *value;
+{
+	Tcl_Obj *result;
+
+	if (PyString_Check(value))
+		return Tcl_NewStringObj(PyString_AS_STRING(value),
+					PyString_GET_SIZE(value));
+	else if (PyInt_Check(value))
+		return Tcl_NewLongObj(PyInt_AS_LONG(value));
+	else if (PyFloat_Check(value))
+		return Tcl_NewDoubleObj(PyFloat_AS_DOUBLE(value));
+	else if (PyTuple_Check(value)) {
+		Tcl_Obj **argv = (Tcl_Obj**)
+			ckalloc(PyTuple_Size(value)*sizeof(Tcl_Obj*));
+		int i;
+		if(!argv)
+		  return 0;
+		for(i=0;i<PyTuple_Size(value);i++)
+		  argv[i] = AsObj(PyTuple_GetItem(value,i));
+		result = Tcl_NewListObj(PyTuple_Size(value), argv);
+		ckfree(FREECAST argv);
+		return result;
+	}
+	else if (PyUnicode_Check(value)) {
+		PyObject* utf8 = PyUnicode_AsUTF8String (value);
+		if (!utf8)
+			return 0;
+		return Tcl_NewStringObj (PyString_AS_STRING (utf8),
+					 PyString_GET_SIZE (utf8));
+	}
+	else {
+		PyObject *v = PyObject_Str(value);
+		if (!v)
+			return 0;
+		result = AsObj(v);
+		Py_DECREF(v);
+		return result;
+	}
+}
 
 
 /**** Tkapp Object ****/
@@ -523,111 +564,65 @@ Tkapp_Call(self, args)
 	PyObject *self;
 	PyObject *args;
 {
-	/* This is copied from Merge() */
-	PyObject *tmp = NULL;
-	char *argvStore[ARGSZ];
-	char **argv = NULL;
-	int fvStore[ARGSZ];
-	int *fv = NULL;
-	int argc = 0, i;
-	PyObject *res = NULL; /* except this has a different type */
-	Tcl_CmdInfo info; /* and this is added */
-	Tcl_Interp *interp = Tkapp_Interp(self); /* and this too */
+	Tcl_Obj *objStore[ARGSZ];
+	Tcl_Obj **objv = NULL;
+	int objc = 0, i;
+	PyObject *res = NULL;
+	Tcl_Interp *interp = Tkapp_Interp(self);
+	/* Could add TCL_EVAL_GLOBAL if wrapped by GlobalCall... */
+	int flags = TCL_EVAL_DIRECT;
 
-	if (!(tmp = PyList_New(0)))
-	    return NULL;
-
-	argv = argvStore;
-	fv = fvStore;
+	objv = objStore;
 
 	if (args == NULL)
-		argc = 0;
+		objc = 0;
 
 	else if (!PyTuple_Check(args)) {
-		argc = 1;
-		fv[0] = 0;
-		argv[0] = AsString(args, tmp);
+		objc = 1;
+		objv[0] = AsObj(args);
+		if (objv[0] == 0)
+			goto finally;
+		Tcl_IncrRefCount(objv[0]);
 	}
 	else {
-		argc = PyTuple_Size(args);
+		objc = PyTuple_Size(args);
 
-		if (argc > ARGSZ) {
-			argv = (char **)ckalloc(argc * sizeof(char *));
-			fv = (int *)ckalloc(argc * sizeof(int));
-			if (argv == NULL || fv == NULL) {
+		if (objc > ARGSZ) {
+			objv = (Tcl_Obj **)ckalloc(objc * sizeof(char *));
+			if (objv == NULL) {
 				PyErr_NoMemory();
 				goto finally;
 			}
 		}
 
-		for (i = 0; i < argc; i++) {
+		for (i = 0; i < objc; i++) {
 			PyObject *v = PyTuple_GetItem(args, i);
-			if (PyTuple_Check(v)) {
-				fv[i] = 1;
-				if (!(argv[i] = Merge(v)))
-					goto finally;
-			}
-			else if (v == Py_None) {
-				argc = i;
-				break;
-			}
-			else {
-				fv[i] = 0;
-				argv[i] = AsString(v, tmp);
-			}
+			objv[i] = AsObj(v);
+			if (!objv[i])
+				goto finally;
+			Tcl_IncrRefCount(objv[i]);
 		}
 	}
-	/* End code copied from Merge() */
 
-	/* All this to avoid a call to Tcl_Merge() and the corresponding call
-	   to Tcl_SplitList() inside Tcl_Eval()...  It can save a bundle! */
-	if (Py_VerboseFlag >= 2) {
-		for (i = 0; i < argc; i++)
-			PySys_WriteStderr("%s ", argv[i]);
-	}
 	ENTER_TCL
-	info.proc = NULL;
-	if (argc < 1 ||
-	    !Tcl_GetCommandInfo(interp, argv[0], &info) ||
-	    info.proc == NULL)
-	{
-		char *cmd;
-		cmd = Tcl_Merge(argc, argv);
-		i = Tcl_Eval(interp, cmd);
-		ckfree(cmd);
-	}
-	else {
-		Tcl_ResetResult(interp);
-		i = (*info.proc)(info.clientData, interp, argc, argv);
-	}
+
+	i = Tcl_EvalObjv(interp, objc, objv, flags);
+
 	ENTER_OVERLAP
-	if (info.proc == NULL && Py_VerboseFlag >= 2)
-		PySys_WriteStderr("... use TclEval ");
-	if (i == TCL_ERROR) {
-		if (Py_VerboseFlag >= 2)
-			PySys_WriteStderr("... error: '%s'\n",
-				interp->result);
+	if (i == TCL_ERROR)
 		Tkinter_Error(self);
-	}
-	else {
-		if (Py_VerboseFlag >= 2)
-			PySys_WriteStderr("-> '%s'\n", interp->result);
-		res = PyString_FromString(interp->result);
-	}
+	else
+		/* We could request the object result here, but doing
+		   so would confuse applications that expect a string. */
+		res = PyString_FromString(Tcl_GetStringResult(interp));
+
 	LEAVE_OVERLAP_TCL
 
-	/* Copied from Merge() again */
   finally:
-	for (i = 0; i < argc; i++)
-		if (fv[i]) {
-			ckfree(argv[i]);
-		}
-	if (argv != argvStore)
-		ckfree(FREECAST argv);
-	if (fv != fvStore)
-		ckfree(FREECAST fv);
-
-	Py_DECREF(tmp);
+	for (i = 0; i < objc; i++)
+		Tcl_DecrRefCount(objv[i]);
+	if (objv != objStore)
+		ckfree(FREECAST objv);
 	return res;
 }