_tkinter.c

/***********************************************************
Copyright (C) 1994 Steen Lumholt.

                        All Rights Reserved

******************************************************************/

/* _tkinter.c -- Interface to libtk.a and libtcl.a. */

/* TCL/TK VERSION INFO:

	Only Tcl/Tk 8.2 and later are supported.  Older versions are not
	supported.  (Use Python 2.2 if you cannot upgrade your Tcl/Tk
	libraries.)
*/

/* XXX Further speed-up ideas, involving Tcl 8.0 features:

   - Register a new Tcl type, "Python callable", which can be called more
   efficiently and passed to Tcl_EvalObj() directly (if this is possible).

*/


#include "Python.h"
#include <ctype.h>

#ifdef WITH_THREAD
#include "pythread.h"
#endif

#ifdef MS_WINDOWS
#include <windows.h>
#endif

/* Allow using this code in Python 2.[12] */
#ifndef PyDoc_STRVAR
#define PyDoc_STRVAR(name,str) static char name[] = str
#endif

#ifndef PyMODINIT_FUNC
#define PyMODINIT_FUNC void
#endif

#ifndef PyBool_Check
#define PyBool_Check(o)       0
#define PyBool_FromLong       PyLong_FromLong
#endif

/* Starting with Tcl 8.4, many APIs offer const-correctness.  Unfortunately,
   making _tkinter correct for this API means to break earlier
   versions. USE_COMPAT_CONST allows to make _tkinter work with both 8.4 and
   earlier versions. Once Tcl releases before 8.4 don't need to be supported
   anymore, this should go. */
#define USE_COMPAT_CONST

/* If Tcl is compiled for threads, we must also define TCL_THREAD. We define
   it always; if Tcl is not threaded, the thread functions in
   Tcl are empty.  */
#define TCL_THREADS

#ifdef TK_FRAMEWORK
#include <Tcl/tcl.h>
#include <Tk/tk.h>
#else
#include <tcl.h>
#include <tk.h>
#endif

/* For Tcl 8.2 and 8.3, CONST* is not defined (except on Cygwin). */
#ifndef CONST84_RETURN
#define CONST84_RETURN
#undef CONST
#define CONST
#endif

#define TKMAJORMINOR (TK_MAJOR_VERSION*1000 + TK_MINOR_VERSION)

#if TKMAJORMINOR < 8002
#error "Tk older than 8.2 not supported"
#endif

/* Unicode conversion assumes that Tcl_UniChar is two bytes.
   We cannot test this directly, so we test UTF-8 size instead,
   expecting that TCL_UTF_MAX is changed if Tcl ever supports
   either UTF-16 or UCS-4.
   Redhat 8 sets TCL_UTF_MAX to 6, and uses wchar_t for
   Tcl_Unichar. This is also ok as long as Python uses UCS-4,
   as well.
*/
#if TCL_UTF_MAX != 3 && !(defined(Py_UNICODE_WIDE) && TCL_UTF_MAX==6)
#error "unsupported Tcl configuration"
#endif

#if !(defined(MS_WINDOWS) || defined(__CYGWIN__))
#define HAVE_CREATEFILEHANDLER
#endif

#ifdef HAVE_CREATEFILEHANDLER

/* This bit is to ensure that TCL_UNIX_FD is defined and doesn't interfere
   with the proper calculation of FHANDLETYPE == TCL_UNIX_FD below. */
#ifndef TCL_UNIX_FD
#  ifdef TCL_WIN_SOCKET
#    define TCL_UNIX_FD (! TCL_WIN_SOCKET)
#  else
#    define TCL_UNIX_FD 1
#  endif
#endif

/* Tcl_CreateFileHandler() changed several times; these macros deal with the
   messiness.  In Tcl 8.0 and later, it is not available on Windows (and on
   Unix, only because Jack added it back); when available on Windows, it only
   applies to sockets. */

#ifdef MS_WINDOWS
#define FHANDLETYPE TCL_WIN_SOCKET
#else
#define FHANDLETYPE TCL_UNIX_FD
#endif

/* If Tcl can wait for a Unix file descriptor, define the EventHook() routine
   which uses this to handle Tcl events while the user is typing commands. */

#if FHANDLETYPE == TCL_UNIX_FD
#define WAIT_FOR_STDIN
#endif

#endif /* HAVE_CREATEFILEHANDLER */

#ifdef MS_WINDOWS
#include <conio.h>
#define WAIT_FOR_STDIN
#endif

#ifdef WITH_THREAD

/* The threading situation is complicated.  Tcl is not thread-safe, except
   when configured with --enable-threads.
   So we need to use a lock around all uses of Tcl.  Previously, the Python
   interpreter lock was used for this.  However, this causes problems when
   other Python threads need to run while Tcl is blocked waiting for events.

   To solve this problem, a separate lock for Tcl is introduced.  Holding it
   is incompatible with holding Python's interpreter lock.  The following four
   macros manipulate both locks together.

   ENTER_TCL and LEAVE_TCL are brackets, just like Py_BEGIN_ALLOW_THREADS and
   Py_END_ALLOW_THREADS.  They should be used whenever a call into Tcl is made
   that could call an event handler, or otherwise affect the state of a Tcl
   interpreter.  These assume that the surrounding code has the Python
   interpreter lock; inside the brackets, the Python interpreter lock has been
   released and the lock for Tcl has been acquired.

   Sometimes, it is necessary to have both the Python lock and the Tcl lock.
   (For example, when transferring data from the Tcl interpreter result to a
   Python string object.)  This can be done by using different macros to close
   the ENTER_TCL block: ENTER_OVERLAP reacquires the Python lock (and restores
   the thread state) but doesn't release the Tcl lock; LEAVE_OVERLAP_TCL
   releases the Tcl lock.

   By contrast, ENTER_PYTHON and LEAVE_PYTHON are used in Tcl event
   handlers when the handler needs to use Python.  Such event handlers are
   entered while the lock for Tcl is held; the event handler presumably needs
   to use Python.  ENTER_PYTHON releases the lock for Tcl and acquires
   the Python interpreter lock, restoring the appropriate thread state, and
   LEAVE_PYTHON releases the Python interpreter lock and re-acquires the lock
   for Tcl.  It is okay for ENTER_TCL/LEAVE_TCL pairs to be contained inside
   the code between ENTER_PYTHON and LEAVE_PYTHON.

   These locks expand to several statements and brackets; they should not be
   used in branches of if statements and the like.

   If Tcl is threaded, this approach won't work anymore. The Tcl interpreter is
   only valid in the thread that created it, and all Tk activity must happen in this
   thread, also. That means that the mainloop must be invoked in the thread that
   created the interpreter. Invoking commands from other threads is possible;
   _tkinter will queue an event for the interpreter thread, which will then
   execute the command and pass back the result. If the main thread is not in the
   mainloop, and invoking commands causes an exception; if the main loop is running
   but not processing events, the command invocation will block.

   In addition, for a threaded Tcl, a single global tcl_tstate won't be sufficient
   anymore, since multiple Tcl interpreters may simultaneously dispatch in different
   threads. So we use the Tcl TLS API.

*/

static PyThread_type_lock tcl_lock = 0;

#ifdef TCL_THREADS
static Tcl_ThreadDataKey state_key;
typedef PyThreadState *ThreadSpecificData;
#define tcl_tstate (*(PyThreadState**)Tcl_GetThreadData(&state_key, sizeof(PyThreadState*)))
#else
static PyThreadState *tcl_tstate = NULL;
#endif

#define ENTER_TCL \
	{ PyThreadState *tstate = PyThreadState_Get(); Py_BEGIN_ALLOW_THREADS \
	    if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1); tcl_tstate = tstate;

#define LEAVE_TCL \
    tcl_tstate = NULL; if(tcl_lock)PyThread_release_lock(tcl_lock); Py_END_ALLOW_THREADS}

#define ENTER_OVERLAP \
	Py_END_ALLOW_THREADS

#define LEAVE_OVERLAP_TCL \
	tcl_tstate = NULL; if(tcl_lock)PyThread_release_lock(tcl_lock); }

#define ENTER_PYTHON \
	{ PyThreadState *tstate = tcl_tstate; tcl_tstate = NULL; \
	    if(tcl_lock)PyThread_release_lock(tcl_lock); PyEval_RestoreThread((tstate)); }

#define LEAVE_PYTHON \
	{ PyThreadState *tstate = PyEval_SaveThread(); \
	    if(tcl_lock)PyThread_acquire_lock(tcl_lock, 1); tcl_tstate = tstate; }

#define CHECK_TCL_APPARTMENT \
	if (((TkappObject *)self)->threaded && \
	    ((TkappObject *)self)->thread_id != Tcl_GetCurrentThread()) { \
		PyErr_SetString(PyExc_RuntimeError, "Calling Tcl from different appartment"); \
		return 0; \
	}

#else

#define ENTER_TCL
#define LEAVE_TCL
#define ENTER_OVERLAP
#define LEAVE_OVERLAP_TCL
#define ENTER_PYTHON
#define LEAVE_PYTHON
#define CHECK_TCL_APPARTMENT

#endif

#ifndef FREECAST
#define FREECAST (char *)
#endif

/**** Tkapp Object Declaration ****/

static PyTypeObject Tkapp_Type;

typedef struct {
	PyObject_HEAD
	Tcl_Interp *interp;
	int wantobjects;
	int threaded; /* True if tcl_platform[threaded] */
	Tcl_ThreadId thread_id;
	int dispatching;
	/* We cannot include tclInt.h, as this is internal.
	   So we cache interesting types here. */
	Tcl_ObjType *BooleanType;
	Tcl_ObjType *ByteArrayType;
	Tcl_ObjType *DoubleType;
	Tcl_ObjType *IntType;
	Tcl_ObjType *ListType;
	Tcl_ObjType *ProcBodyType;
	Tcl_ObjType *StringType;
} TkappObject;

#define Tkapp_Check(v) (Py_TYPE(v) == &Tkapp_Type)
#define Tkapp_Interp(v) (((TkappObject *) (v))->interp)
#define Tkapp_Result(v) Tcl_GetStringResult(Tkapp_Interp(v))

#define DEBUG_REFCNT(v) (printf("DEBUG: id=%p, refcnt=%i\n", \
(void *) v, Py_REFCNT(v)))



/**** Error Handling ****/

static PyObject *Tkinter_TclError;
static int quitMainLoop = 0;
static int errorInCmd = 0;
static PyObject *excInCmd;
static PyObject *valInCmd;
static PyObject *trbInCmd;



static PyObject *
Tkinter_Error(PyObject *v)
{
	PyErr_SetString(Tkinter_TclError, Tkapp_Result(v));
	return NULL;
}



/**** Utils ****/

static int Tkinter_busywaitinterval = 20;

#ifdef WITH_THREAD
#ifndef MS_WINDOWS

/* Millisecond sleep() for Unix platforms. */

static void
Sleep(int milli)
{
	/* XXX Too bad if you don't have select(). */
	struct timeval t;
	t.tv_sec = milli/1000;
	t.tv_usec = (milli%1000) * 1000;
	select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &t);
}
#endif /* MS_WINDOWS */

/* Wait up to 1s for the mainloop to come up. */

static int
WaitForMainloop(TkappObject* self)
{
	int i;
	for (i = 0; i < 10; i++) {
		if (self->dispatching)
			return 1;
		Py_BEGIN_ALLOW_THREADS
		Sleep(100);
		Py_END_ALLOW_THREADS
	}
	if (self->dispatching)
		return 1;
	PyErr_SetString(PyExc_RuntimeError, "main thread is not in main loop");
	return 0;
}
#endif /* WITH_THREAD */


static char *
AsString(PyObject *value, PyObject *tmp)
{
	if (PyBytes_Check(value))
		return PyBytes_AsString(value);
	else if (PyUnicode_Check(value)) {
		PyObject *v = PyUnicode_AsUTF8String(value);
		if (v == NULL)
			return NULL;
		if (PyList_Append(tmp, v) != 0) {
			Py_DECREF(v);
			return NULL;
		}
		Py_DECREF(v);
		return PyBytes_AsString(v);
	}
	else {
		PyObject *v = PyObject_Str(value);
		if (v == NULL)
			return NULL;
		if (PyList_Append(tmp, v) != 0) {
			Py_DECREF(v);
			return NULL;
		}
		Py_DECREF(v);
		return PyBytes_AsString(v);
	}
}



#define ARGSZ 64

static char *
Merge(PyObject *args)
{
	PyObject *tmp = NULL;
	char *argvStore[ARGSZ];
	char **argv = NULL;
	int fvStore[ARGSZ];
	int *fv = NULL;
	int argc = 0, fvc = 0, i;
	char *res = NULL;

	if (!(tmp = PyList_New(0)))
	    return NULL;

	argv = argvStore;
	fv = fvStore;

	if (args == NULL)
		argc = 0;

	else if (!PyTuple_Check(args)) {
		argc = 1;
		fv[0] = 0;
		if (!(argv[0] = AsString(args, tmp)))
			goto finally;
	}
	else {
		argc = PyTuple_Size(args);

		if (argc > ARGSZ) {
			argv = (char **)ckalloc(argc * sizeof(char *));
			fv = (int *)ckalloc(argc * sizeof(int));
			if (argv == NULL || fv == NULL) {
				PyErr_NoMemory();
				goto finally;
			}
		}

		for (i = 0; i < argc; i++) {
			PyObject *v = PyTuple_GetItem(args, i);
			if (PyTuple_Check(v)) {
				fv[i] = 1;
				if (!(argv[i] = Merge(v)))
					goto finally;
				fvc++;
			}
			else if (v == Py_None) {
				argc = i;
				break;
			}
			else {
				fv[i] = 0;
				if (!(argv[i] = AsString(v, tmp)))
					goto finally;
				fvc++;
			}
		}
	}
	res = Tcl_Merge(argc, argv);
	if (res == NULL)
		PyErr_SetString(Tkinter_TclError, "merge failed");

  finally:
	for (i = 0; i < fvc; i++)
		if (fv[i]) {
			ckfree(argv[i]);
		}
	if (argv != argvStore)
		ckfree(FREECAST argv);
	if (fv != fvStore)
		ckfree(FREECAST fv);

	Py_DECREF(tmp);
	return res;
}



static PyObject *
Split(char *list)
{
	int argc;
	char **argv;
	PyObject *v;

	if (list == NULL) {
		Py_INCREF(Py_None);
		return Py_None;
	}

	if (Tcl_SplitList((Tcl_Interp *)NULL, list, &argc, &argv) != TCL_OK) {
		/* Not a list.
		 * Could be a quoted string containing funnies, e.g. {"}.
		 * Return the string itself.
		 */
		return PyUnicode_FromString(list);
	}

	if (argc == 0)
		v = PyUnicode_FromString("");
	else if (argc == 1)
		v = PyUnicode_FromString(argv[0]);
	else if ((v = PyTuple_New(argc)) != NULL) {
		int i;
		PyObject *w;

		for (i = 0; i < argc; i++) {
			if ((w = Split(argv[i])) == NULL) {
				Py_DECREF(v);
				v = NULL;
				break;
			}
			PyTuple_SetItem(v, i, w);
		}
	}
	Tcl_Free(FREECAST argv);
	return v;
}

/* In some cases, Tcl will still return strings that are supposed to be
   lists. SplitObj walks through a nested tuple, finding string objects that
   need to be split. */

static PyObject *
SplitObj(PyObject *arg)
{
	if (PyTuple_Check(arg)) {
		int i, size;
		PyObject *elem, *newelem, *result;

		size = PyTuple_Size(arg);
		result = NULL;
		/* Recursively invoke SplitObj for all tuple items.
		   If this does not return a new object, no action is
		   needed. */
		for(i = 0; i < size; i++) {
			elem = PyTuple_GetItem(arg, i);
			newelem = SplitObj(elem);
			if (!newelem) {
				Py_XDECREF(result);
				return NULL;
			}
			if (!result) {
				int k;
				if (newelem == elem) {
					Py_DECREF(newelem);
					continue;
				}
				result = PyTuple_New(size);
				if (!result)
					return NULL;
				for(k = 0; k < i; k++) {
					elem = PyTuple_GetItem(arg, k);
					Py_INCREF(elem);
					PyTuple_SetItem(result, k, elem);
				}
			}
			PyTuple_SetItem(result, i, newelem);
		}
		if (result)
			return result;
		/* Fall through, returning arg. */
	}
	else if (PyBytes_Check(arg)) {
		int argc;
		char **argv;
		char *list = PyBytes_AsString(arg);

		if (Tcl_SplitList((Tcl_Interp *)NULL, list, &argc, &argv) != TCL_OK) {
			Py_INCREF(arg);
			return arg;
		}
		Tcl_Free(FREECAST argv);
		if (argc > 1)
			return Split(PyBytes_AsString(arg));
		/* Fall through, returning arg. */
	}
	Py_INCREF(arg);
	return arg;
}


/**** Tkapp Object ****/

#ifndef WITH_APPINIT
int
Tcl_AppInit(Tcl_Interp *interp)
{
	Tk_Window main;
	const char * _tkinter_skip_tk_init;

	if (Tcl_Init(interp) == TCL_ERROR) {
		PySys_WriteStderr("Tcl_Init error: %s\n", Tcl_GetStringResult(interp));
		return TCL_ERROR;
	}
	_tkinter_skip_tk_init =	Tcl_GetVar(interp, "_tkinter_skip_tk_init", TCL_GLOBAL_ONLY);
	if (_tkinter_skip_tk_init == NULL || strcmp(_tkinter_skip_tk_init, "1")	!= 0) {
		main = Tk_MainWindow(interp);
		if (Tk_Init(interp) == TCL_ERROR) {
			PySys_WriteStderr("Tk_Init error: %s\n", Tcl_GetStringResult(interp));
			return TCL_ERROR;
		}
	}
	return TCL_OK;
}
#endif /* !WITH_APPINIT */




/* Initialize the Tk application; see the `main' function in
 * `tkMain.c'.
 */

static void EnableEventHook(void); /* Forward */
static void DisableEventHook(void); /* Forward */

static TkappObject *
Tkapp_New(char *screenName, char *className,
	  int interactive, int wantobjects, int	wantTk, int sync, char *use)
{
	TkappObject *v;
	char *argv0;

	v = PyObject_New(TkappObject, &Tkapp_Type);
	if (v == NULL)
		return NULL;

	v->interp = Tcl_CreateInterp();
	v->wantobjects = wantobjects;
	v->threaded = Tcl_GetVar2Ex(v->interp, "tcl_platform", "threaded",
				    TCL_GLOBAL_ONLY) != NULL;
	v->thread_id = Tcl_GetCurrentThread();
	v->dispatching = 0;

#ifndef TCL_THREADS
	if (v->threaded) {
	    PyErr_SetString(PyExc_RuntimeError, "Tcl is threaded but _tkinter is not");
	    Py_DECREF(v);
	    return 0;
	}
#endif
#ifdef WITH_THREAD
	if (v->threaded && tcl_lock) {
	    /* If Tcl is threaded, we don't need the lock. */
	    PyThread_free_lock(tcl_lock);
	    tcl_lock = NULL;
	}
#endif

	v->BooleanType = Tcl_GetObjType("boolean");
	v->ByteArrayType = Tcl_GetObjType("bytearray");
	v->DoubleType = Tcl_GetObjType("double");
	v->IntType = Tcl_GetObjType("int");
	v->ListType = Tcl_GetObjType("list");
	v->ProcBodyType = Tcl_GetObjType("procbody");
	v->StringType = Tcl_GetObjType("string");

	/* Delete the 'exit' command, which can screw things up */
	Tcl_DeleteCommand(v->interp, "exit");

	if (screenName != NULL)
		Tcl_SetVar2(v->interp, "env", "DISPLAY",
			    screenName, TCL_GLOBAL_ONLY);

	if (interactive)
		Tcl_SetVar(v->interp, "tcl_interactive", "1", TCL_GLOBAL_ONLY);
	else
		Tcl_SetVar(v->interp, "tcl_interactive", "0", TCL_GLOBAL_ONLY);

	/* This is used to get the application class for Tk 4.1 and up */
	argv0 = (char*)ckalloc(strlen(className) + 1);
	if (!argv0) {
		PyErr_NoMemory();
		Py_DECREF(v);
		return NULL;
	}

	strcpy(argv0, className);
	if (isupper(Py_CHARMASK(argv0[0])))
		argv0[0] = tolower(Py_CHARMASK(argv0[0]));
	Tcl_SetVar(v->interp, "argv0", argv0, TCL_GLOBAL_ONLY);
	ckfree(argv0);

	if (! wantTk) {
	    Tcl_SetVar(v->interp, "_tkinter_skip_tk_init", "1",	TCL_GLOBAL_ONLY);
	}

	/* some initial arguments need to be in argv */
	if (sync || use) {
		char *args;
		int len = 0;

		if (sync)
			len += sizeof "-sync";
		if (use)
			len += strlen(use) + sizeof "-use ";

		args = (char*)ckalloc(len);
		if (!args) {
			PyErr_NoMemory();
			Py_DECREF(v);
			return NULL;
		}

		args[0] = '\0';
		if (sync)
			strcat(args, "-sync");
		if (use) {
			if (sync)
				strcat(args, " ");
			strcat(args, "-use ");
			strcat(args, use);
		}

		Tcl_SetVar(v->interp, "argv", args, TCL_GLOBAL_ONLY);
		ckfree(args);
	}

	if (Tcl_AppInit(v->interp) != TCL_OK) {
		PyObject *result = Tkinter_Error((PyObject *)v);
		Py_DECREF((PyObject *)v);
		return (TkappObject *)result;
	}

	EnableEventHook();

	return v;
}


static void
Tkapp_ThreadSend(TkappObject *self, Tcl_Event *ev,
		 Tcl_Condition *cond, Tcl_Mutex *mutex)
{
	Py_BEGIN_ALLOW_THREADS;
	Tcl_MutexLock(mutex);
	Tcl_ThreadQueueEvent(self->thread_id, ev, TCL_QUEUE_TAIL);
	Tcl_ThreadAlert(self->thread_id);
	Tcl_ConditionWait(cond, mutex, NULL);
	Tcl_MutexUnlock(mutex);
	Py_END_ALLOW_THREADS
}


/** Tcl Eval **/

typedef struct {
	PyObject_HEAD
	Tcl_Obj *value;
	PyObject *string; /* This cannot cause cycles. */
} PyTclObject;

static PyTypeObject PyTclObject_Type;
#define PyTclObject_Check(v)	((v)->ob_type == &PyTclObject_Type)

static PyObject *
newPyTclObject(Tcl_Obj *arg)
{
	PyTclObject *self;
	self = PyObject_New(PyTclObject, &PyTclObject_Type);
	if (self == NULL)
		return NULL;
	Tcl_IncrRefCount(arg);
	self->value = arg;
	self->string = NULL;
	return (PyObject*)self;
}

static void
PyTclObject_dealloc(PyTclObject *self)
{
	Tcl_DecrRefCount(self->value);
	Py_XDECREF(self->string);
	PyObject_Del(self);
}

static char*
PyTclObject_TclString(PyObject *self)
{
	return Tcl_GetString(((PyTclObject*)self)->value);
}

/* Like _str, but create Unicode if necessary. */
PyDoc_STRVAR(PyTclObject_string__doc__,
"the string representation of this object, either as str or bytes");

static PyObject *
PyTclObject_string(PyTclObject *self, void *ignored)
{
	char *s;
	int len;
	if (!self->string) {
		s = Tcl_GetStringFromObj(self->value, &len);
		self->string = PyUnicode_FromStringAndSize(s, len);
		if (!self->string)
			return NULL;
	}
	Py_INCREF(self->string);
	return self->string;
}

static PyObject *
PyTclObject_str(PyTclObject *self, void *ignored)
{
	char *s;
	int len;
	if (self->string && PyUnicode_Check(self->string)) {
		Py_INCREF(self->string);
		return self->string;
	}
	/* XXX Could chache result if it is non-ASCII. */
	s = Tcl_GetStringFromObj(self->value, &len);
	return PyUnicode_DecodeUTF8(s, len, "strict");
}

static PyObject *
PyTclObject_repr(PyTclObject *self)
{
	return PyUnicode_FromFormat("<%s object at %p>",
	                            self->value->typePtr->name, self->value);
}

#define TEST_COND(cond) ((cond) ? Py_True : Py_False)

static PyObject *
PyTclObject_richcompare(PyObject *self, PyObject *other, int op)
{
	int result;
	PyObject *v;

	/* neither argument should be NULL, unless something's gone wrong */
	if (self == NULL || other == NULL) {
		PyErr_BadInternalCall();
		return NULL;
	}

	/* both arguments should be instances of PyTclObject */
	if (!PyTclObject_Check(self) || !PyTclObject_Check(other)) {
		v = Py_NotImplemented;
		goto finished;
	}

	if (self == other)
		/* fast path when self and other are identical */
		result = 0;
	else
		result = strcmp(Tcl_GetString(((PyTclObject *)self)->value),
				Tcl_GetString(((PyTclObject *)other)->value));
	/* Convert return value to a Boolean */
	switch (op) {
	case Py_EQ:
		v = TEST_COND(result == 0);
		break;
	case Py_NE:
		v = TEST_COND(result != 0);
		break;
	case Py_LE:
		v = TEST_COND(result <= 0);
		break;
	case Py_GE:
		v = TEST_COND(result >= 0);
		break;
	case Py_LT:
		v = TEST_COND(result < 0);
		break;
	case Py_GT:
		v = TEST_COND(result > 0);
		break;
	default:
		PyErr_BadArgument();
		return NULL;
	}
  finished:
	Py_INCREF(v);
	return v;
}

PyDoc_STRVAR(get_typename__doc__, "name of the Tcl type");

static PyObject*
get_typename(PyTclObject* obj, void* ignored)
{
	return PyUnicode_FromString(obj->value->typePtr->name);
}


static PyGetSetDef PyTclObject_getsetlist[] = {
	{"typename", (getter)get_typename, NULL, get_typename__doc__},
	{"string", (getter)PyTclObject_string, NULL,
	 PyTclObject_string__doc__},
	{0},
};

static PyTypeObject PyTclObject_Type = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"_tkinter.Tcl_Obj",		/*tp_name*/
	sizeof(PyTclObject),		/*tp_basicsize*/
	0,				/*tp_itemsize*/
	/* methods */
	(destructor)PyTclObject_dealloc,/*tp_dealloc*/
	0,				/*tp_print*/
	0,				/*tp_getattr*/
	0,				/*tp_setattr*/
	0,				/*tp_reserved*/
	(reprfunc)PyTclObject_repr,	/*tp_repr*/
	0,				/*tp_as_number*/
	0,				/*tp_as_sequence*/
	0,				/*tp_as_mapping*/
	0,				/*tp_hash*/
	0,				/*tp_call*/
	(reprfunc)PyTclObject_str,	/*tp_str*/
	PyObject_GenericGetAttr,	/*tp_getattro*/
	0,				/*tp_setattro*/
	0,				/*tp_as_buffer*/
	Py_TPFLAGS_DEFAULT,		/*tp_flags*/
	0,				/*tp_doc*/
	0,				/*tp_traverse*/
	0,				/*tp_clear*/
	PyTclObject_richcompare,	/*tp_richcompare*/
	0,				/*tp_weaklistoffset*/
	0,				/*tp_iter*/
	0,				/*tp_iternext*/
	0,				/*tp_methods*/
	0,				/*tp_members*/
	PyTclObject_getsetlist,		/*tp_getset*/
	0,				/*tp_base*/
	0,				/*tp_dict*/
	0,				/*tp_descr_get*/
	0,				/*tp_descr_set*/
	0,				/*tp_dictoffset*/
	0,				/*tp_init*/
	0,				/*tp_alloc*/
	0,				/*tp_new*/
	0,				/*tp_free*/
	0,				/*tp_is_gc*/
};

static Tcl_Obj*
AsObj(PyObject *value)
{
	Tcl_Obj *result;
	long longVal;
	int overflow;

	if (PyBytes_Check(value))
		return Tcl_NewStringObj(PyBytes_AS_STRING(value),
					PyBytes_GET_SIZE(value));
	else if (PyBool_Check(value))
		return Tcl_NewBooleanObj(PyObject_IsTrue(value));
	else if (PyLong_CheckExact(value) &&
		 ((longVal = PyLong_AsLongAndOverflow(value, &overflow)),
		  !overflow)) {
		/* If there is an overflow in the long conversion,
		   fall through to default object handling. */
		return Tcl_NewLongObj(longVal);
	}
	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)) {
		Py_UNICODE *inbuf = PyUnicode_AS_UNICODE(value);
		Py_ssize_t size = PyUnicode_GET_SIZE(value);
		/* This #ifdef assumes that Tcl uses UCS-2.
		   See TCL_UTF_MAX test above. */
#if defined(Py_UNICODE_WIDE) && TCL_UTF_MAX == 3
		Tcl_UniChar *outbuf = NULL;
		Py_ssize_t i;
		size_t allocsize = ((size_t)size) * sizeof(Tcl_UniChar);
		if (allocsize >= size)
			outbuf = (Tcl_UniChar*)ckalloc(allocsize);
		/* Else overflow occurred, and we take the next exit */
		if (!outbuf) {
			PyErr_NoMemory();
			return NULL;
		}
		for (i = 0; i < size; i++) {
			if (inbuf[i] >= 0x10000) {
				/* Tcl doesn't do UTF-16, yet. */
				PyErr_SetString(PyExc_ValueError,
						"unsupported character");
				ckfree(FREECAST outbuf);
				return NULL;
			}
			outbuf[i] = inbuf[i];
		}
		result = Tcl_NewUnicodeObj(outbuf, size);
		ckfree(FREECAST outbuf);
		return result;
#else
		return Tcl_NewUnicodeObj(inbuf, size);
#endif

	}
	else if(PyTclObject_Check(value)) {
		Tcl_Obj *v = ((PyTclObject*)value)->value;
		Tcl_IncrRefCount(v);
		return v;
	}
	else {
		PyObject *v = PyObject_Str(value);
		if (!v)
			return 0;
		result = AsObj(v);
		Py_DECREF(v);
		return result;
	}
}

static PyObject*
FromObj(PyObject* tkapp, Tcl_Obj *value)
{
	PyObject *result = NULL;
	TkappObject *app = (TkappObject*)tkapp;

	if (value->typePtr == NULL) {
		return PyUnicode_FromStringAndSize(value->bytes,
						   value->length);
	}

	if (value->typePtr == app->BooleanType) {
		result = value->internalRep.longValue ? Py_True : Py_False;