/* 
 * tkBind.c --
 *
 *	This file provides procedures that associate Tcl commands
 *	with X events or sequences of X events.
 *
 * Copyright (c) 1989-1994 The Regents of the University of California.
 * Copyright (c) 1994-1996 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * SCCS: @(#) tkBind.c 1.124 96/12/05 14:47:40
 */

#include "tkPort.h"
#include "tkInt.h"

/*
 * File structure:
 *
 * Structure definitions and static variables.
 *
 * Init/Free this package.
 *
 * Tcl "bind" command (actually located in tkCmds.c).
 * "bind" command implementation.
 * "bind" implementation helpers.
 *
 * Tcl "event" command.
 * "event" command implementation.
 * "event" implementation helpers.
 *
 * Package-specific common helpers.
 *
 * Non-package-specific helpers.
 */


/*
 * The following union is used to hold the detail information from an
 * XEvent (including Tk's XVirtualEvent extension).
 */
typedef union {
    KeySym	keySym;	    /* KeySym that corresponds to xkey.keycode. */
    int		button;	    /* Button that was pressed (xbutton.button). */
    Tk_Uid	name;	    /* Tk_Uid of virtual event. */
    ClientData	clientData; /* Used when type of Detail is unknown, and to
			     * ensure that all bytes of Detail are initialized
			     * when this structure is used in a hash key. */
} Detail;

/*
 * The structure below represents a binding table.  A binding table
 * represents a domain in which event bindings may occur.  It includes
 * a space of objects relative to which events occur (usually windows,
 * but not always), a history of recent events in the domain, and
 * a set of mappings that associate particular Tcl commands with sequences
 * of events in the domain.  Multiple binding tables may exist at once,
 * either because there are multiple applications open, or because there
 * are multiple domains within an application with separate event
 * bindings for each (for example, each canvas widget has a separate
 * binding table for associating events with the items in the canvas).
 *
 * Note: it is probably a bad idea to reduce EVENT_BUFFER_SIZE much
 * below 30.  To see this, consider a triple mouse button click while
 * the Shift key is down (and auto-repeating).  There may be as many
 * as 3 auto-repeat events after each mouse button press or release
 * (see the first large comment block within Tk_BindEvent for more on
 * this), for a total of 20 events to cover the three button presses
 * and two intervening releases.  If you reduce EVENT_BUFFER_SIZE too
 * much, shift multi-clicks will be lost.
 * 
 */

#define EVENT_BUFFER_SIZE 30
typedef struct BindingTable {
    XEvent eventRing[EVENT_BUFFER_SIZE];/* Circular queue of recent events
					 * (higher indices are for more recent
					 * events). */
    Detail detailRing[EVENT_BUFFER_SIZE];/* "Detail" information (keySym,
					 * button, Tk_Uid, or 0) for each
					 * entry in eventRing. */
    int curEvent;			/* Index in eventRing of most recent
					 * event.  Newer events have higher
					 * indices. */
    Tcl_HashTable patternTable;		/* Used to map from an event to a
					 * list of patterns that may match that
					 * event.  Keys are PatternTableKey
					 * structs, values are (PatSeq *). */
    Tcl_HashTable objectTable;		/* Used to map from an object to a
					 * list of patterns associated with
					 * that object.  Keys are ClientData,
					 * values are (PatSeq *). */
    Tcl_Interp *interp;			/* Interpreter in which commands are
					 * executed. */
} BindingTable;

/*
 * The following structure represents virtual event table.  A virtual event
 * table provides a way to map from platform-specific physical events such
 * as button clicks or key presses to virtual events such as <<Paste>>,
 * <<Close>>, or <<ScrollWindow>>.
 *
 * A virtual event is usually never part of the event stream, but instead is
 * synthesized inline by matching low-level events.  However, a virtual
 * event may be generated by platform-specific code or by Tcl scripts.  In
 * that case, no lookup of the virtual event will need to be done using
 * this table, because the virtual event is actually in the event stream.
 */

typedef struct TkVirtualEventTable {
    Tcl_HashTable patternTable;     /* Used to map from a physical event to
				     * a list of patterns that may match that
				     * event.  Keys PatternTableKey structs,
				     * values are (PatSeq *). */
    Tcl_HashTable virtualTable;	    /* Used to map a virtual event to the
				     * array of physical events that can
				     * trigger it.  Keys are the Tk_Uid names
				     * of the virtual events, values are
				     * PhysicalsOwned structs. */
} TkVirtualEventTable;

/*
 * The following structure is used as a key in a patternTable for both 
 * binding tables and a virtual event tables.
 *
 * In a binding table, the object field corresponds to the binding tag
 * for the widget whose bindings are being accessed.
 *
 * In a virtual event table, the object field is always NULL.  Virtual
 * events are a global definiton and are not tied to a particular
 * binding tag.
 *
 * The same key is used for both types of pattern tables so that the 
 * helper functions that traverse and match patterns will work for both
 * binding tables and virtual event tables.
 */
typedef struct PatternTableKey {
    ClientData object;		/* For binding table, identifies the binding
				 * tag of the object (or class of objects)
				 * relative to which the event occurred.
				 * For virtual event table, always NULL. */
    int type;			/* Type of event (from X). */
    Detail detail;		/* Additional information, such as keysym,
				 * button, Tk_Uid, or 0 if nothing
				 * additional. */
} PatternTableKey;

/*
 * The following structure defines a pattern, which is matched against X
 * events as part of the process of converting X events into Tcl commands.
 */

typedef struct Pattern {
    int eventType;		/* Type of X event, e.g. ButtonPress. */
    int needMods;		/* Mask of modifiers that must be
				 * present (0 means no modifiers are
				 * required). */
    Detail detail;		/* Additional information that must
				 * match event.  Normally this is 0,
				 * meaning no additional information
				 * must match.  For KeyPress and
				 * KeyRelease events, a keySym may
				 * be specified to select a
				 * particular keystroke (0 means any
				 * keystrokes).  For button events,
				 * specifies a particular button (0
				 * means any buttons are OK).  For virtual
				 * events, specifies the Tk_Uid of the
				 * virtual event name (never 0). */
} Pattern;

/*
 * The following structure defines a pattern sequence, which consists of one
 * or more patterns.  In order to trigger, a pattern sequence must match
 * the most recent X events (first pattern to most recent event, next
 * pattern to next event, and so on).  It is used as the hash value in a
 * patternTable for both binding tables and virtual event tables.
 *
 * In a binding table, it is the sequence of physical events that make up
 * a binding for an object.
 * 
 * In a virtual event table, it is the sequence of physical events that
 * define a virtual event.
 *
 * The same structure is used for both types of pattern tables so that the 
 * helper functions that traverse and match patterns will work for both
 * binding tables and virtual event tables.
 */

typedef struct PatSeq {
    int numPats;		/* Number of patterns in sequence (usually
				 * 1). */
    char *command;		/* Command to invoke when this pattern
				 * sequence matches (malloc-ed). */
    int flags;			/* Miscellaneous flag values; see below for
				 * definitions. */
    struct PatSeq *nextSeqPtr;  /* Next in list of all pattern sequences
				 * that have the same initial pattern.  NULL
				 * means end of list. */
    Tcl_HashEntry *hPtr;	/* Pointer to hash table entry for the
				 * initial pattern.  This is the head of the
				 * list of which nextSeqPtr forms a part. */
    struct VirtualOwners *voPtr;/* In a binding table, always NULL.  In a
				 * virtual event table, identifies the array
				 * of virtual events that can be triggered by
				 * this event. */
    struct PatSeq *nextObjPtr;  /* In a binding table, next in list of all
				 * pattern sequences for the same object (NULL
				 * for end of list).  Needed to implement
				 * Tk_DeleteAllBindings.  In a virtual event
				 * table, always NULL. */
    Pattern pats[1];		/* Array of "numPats" patterns.  Only one
				 * element is declared here but in actuality
				 * enough space will be allocated for "numPats"
				 * patterns.  To match, pats[0] must match
				 * event n, pats[1] must match event n-1, etc.
				 */
} PatSeq;

/*
 * Flag values for PatSeq structures:
 *
 * PAT_NEARBY		1 means that all of the events matching
 *			this sequence must occur with nearby X
 *			and Y mouse coordinates and close in time.
 *			This is typically used to restrict multiple
 *			button presses.
 */

#define PAT_NEARBY		1

/*
 * Constants that define how close together two events must be
 * in milliseconds or pixels to meet the PAT_NEARBY constraint:
 */

#define NEARBY_PIXELS		5
#define NEARBY_MS		500


/*
 * The following structure keeps track of all the virtual events that are
 * associated with a particular physical event.  It is pointed to by the
 * voPtr field in a PatSeq in the patternTable of a  virtual event table.
 */

typedef struct VirtualOwners {
    int numOwners;		    /* Number of virtual events to trigger. */
    Tcl_HashEntry *owners[1];	    /* Array of pointers to entries in
				     * virtualTable.  Enough space will
				     * actually be allocated for numOwners
				     * hash entries. */
} VirtualOwners;

/*
 * The following structure is used in the virtualTable of a virtual event
 * table to associate a virtual event with all the physical events that can
 * trigger it.
 */
typedef struct PhysicalsOwned {
    int numOwned;		    /* Number of physical events owned. */
    PatSeq *patSeqs[1];		    /* Array of pointers to physical event
				     * patterns.  Enough space will actually
				     * be allocated to hold numOwned. */
} PhysicalsOwned;


/*
 * One of the following structures exists for each interpreter,
 * associated with the key "tkBind".  This structure keeps track
 * of the current display and screen in the interpreter, so that
 * a script can be invoked whenever the display/screen changes
 * (the script does things like point tkPriv at a display-specific
 * structure).
 */

typedef struct ScreenInfo {
    TkDisplay *curDispPtr;	/* Display for last binding command invoked
				 * in this application. */
    int curScreenIndex;		/* Index of screen for last binding command. */
    int bindingDepth;		/* Number of active instances of Tk_BindEvent
				 * in this application. */
} ScreenInfo;

/*
 * In X11R4 and earlier versions, XStringToKeysym is ridiculously
 * slow.  The data structure and hash table below, along with the
 * code that uses them, implement a fast mapping from strings to
 * keysyms.  In X11R5 and later releases XStringToKeysym is plenty
 * fast so this stuff isn't needed.  The #define REDO_KEYSYM_LOOKUP
 * is normally undefined, so that XStringToKeysym gets used.  It
 * can be set in the Makefile to enable the use of the hash table
 * below.
 */

#ifdef REDO_KEYSYM_LOOKUP
typedef struct {
    char *name;				/* Name of keysym. */
    KeySym value;			/* Numeric identifier for keysym. */
} KeySymInfo;
static KeySymInfo keyArray[] = {
#ifndef lint
#include "ks_names.h"
#endif
    {(char *) NULL, 0}
};
static Tcl_HashTable keySymTable;	/* keyArray hashed by keysym value. */
static Tcl_HashTable nameTable;		/* keyArray hashed by keysym name. */
#endif /* REDO_KEYSYM_LOOKUP */

static int initialized = 0;

/*
 * A hash table is kept to map from the string names of event
 * modifiers to information about those modifiers.  The structure
 * for storing this information, and the hash table built at
 * initialization time, are defined below.
 */

typedef struct {
    char *name;			/* Name of modifier. */
    int mask;			/* Button/modifier mask value,							 * such as Button1Mask. */
    int flags;			/* Various flags;  see below for
				 * definitions. */
} ModInfo;

/*
 * Flags for ModInfo structures:
 *
 * DOUBLE -		Non-zero means duplicate this event,
 *			e.g. for double-clicks.
 * TRIPLE -		Non-zero means triplicate this event,
 *			e.g. for triple-clicks.
 */

#define DOUBLE		1
#define TRIPLE		2

/*
 * The following special modifier mask bits are defined, to indicate
 * logical modifiers such as Meta and Alt that may float among the
 * actual modifier bits.
 */

#define META_MASK	(AnyModifier<<1)
#define ALT_MASK	(AnyModifier<<2)

static ModInfo modArray[] = {
    {"Control",		ControlMask,	0},
    {"Shift",		ShiftMask,	0},
    {"Lock",		LockMask,	0},
    {"Meta",		META_MASK,	0},
    {"M",		META_MASK,	0},
    {"Alt",		ALT_MASK,	0},
    {"B1",		Button1Mask,	0},
    {"Button1",		Button1Mask,	0},
    {"B2",		Button2Mask,	0},
    {"Button2",		Button2Mask,	0},
    {"B3",		Button3Mask,	0},
    {"Button3",		Button3Mask,	0},
    {"B4",		Button4Mask,	0},
    {"Button4",		Button4Mask,	0},
    {"B5",		Button5Mask,	0},
    {"Button5",		Button5Mask,	0},
    {"Mod1",		Mod1Mask,	0},
    {"M1",		Mod1Mask,	0},
    {"Command",		Mod1Mask,	0},
    {"Mod2",		Mod2Mask,	0},
    {"M2",		Mod2Mask,	0},
    {"Option",		Mod2Mask,	0},
    {"Mod3",		Mod3Mask,	0},
    {"M3",		Mod3Mask,	0},
    {"Mod4",		Mod4Mask,	0},
    {"M4",		Mod4Mask,	0},
    {"Mod5",		Mod5Mask,	0},
    {"M5",		Mod5Mask,	0},
    {"Double",		0,		DOUBLE},
    {"Triple",		0,		TRIPLE},
    {"Any",		0,		0},	/* Ignored: historical relic. */
    {NULL,		0,		0}
};
static Tcl_HashTable modTable;

/*
 * This module also keeps a hash table mapping from event names
 * to information about those events.  The structure, an array
 * to use to initialize the hash table, and the hash table are
 * all defined below.
 */

typedef struct {
    char *name;			/* Name of event. */
    int type;			/* Event type for X, such as
				 * ButtonPress. */
    int eventMask;		/* Mask bits (for XSelectInput)
				 * for this event type. */
} EventInfo;

/*
 * Note:  some of the masks below are an OR-ed combination of
 * several masks.  This is necessary because X doesn't report
 * up events unless you also ask for down events.  Also, X
 * doesn't report button state in motion events unless you've
 * asked about button events.
 */

static EventInfo eventArray[] = {
    {"Key",		KeyPress,		KeyPressMask},
    {"KeyPress",	KeyPress,		KeyPressMask},
    {"KeyRelease",	KeyRelease,		KeyPressMask|KeyReleaseMask},
    {"Button",		ButtonPress,		ButtonPressMask},
    {"ButtonPress",	ButtonPress,		ButtonPressMask},
    {"ButtonRelease",	ButtonRelease,
	    ButtonPressMask|ButtonReleaseMask},
    {"Motion",		MotionNotify,
	    ButtonPressMask|PointerMotionMask},
    {"Enter",		EnterNotify,		EnterWindowMask},
    {"Leave",		LeaveNotify,		LeaveWindowMask},
    {"FocusIn",		FocusIn,		FocusChangeMask},
    {"FocusOut",	FocusOut,		FocusChangeMask},
    {"Expose",		Expose,			ExposureMask},
    {"Visibility",	VisibilityNotify,	VisibilityChangeMask},
    {"Destroy",		DestroyNotify,		StructureNotifyMask},
    {"Unmap",		UnmapNotify,		StructureNotifyMask},
    {"Map",		MapNotify,		StructureNotifyMask},
    {"Reparent",	ReparentNotify,		StructureNotifyMask},
    {"Configure",	ConfigureNotify,	StructureNotifyMask},
    {"Gravity",		GravityNotify,		StructureNotifyMask},
    {"Circulate",	CirculateNotify,	StructureNotifyMask},
    {"Property",	PropertyNotify,		PropertyChangeMask},
    {"Colormap",	ColormapNotify,		ColormapChangeMask},
    {"Activate",	ActivateNotify,		ActivateMask},
    {"Deactivate",	DeactivateNotify,	ActivateMask},
    {(char *) NULL,	0,			0}
};
static Tcl_HashTable eventTable;

/*
 * The defines and table below are used to classify events into
 * various groups.  The reason for this is that logically identical
 * fields (e.g. "state") appear at different places in different
 * types of events.  The classification masks can be used to figure
 * out quickly where to extract information from events.
 */

#define KEY			0x1
#define BUTTON			0x2
#define MOTION			0x4
#define CROSSING		0x8
#define FOCUS			0x10
#define EXPOSE			0x20
#define VISIBILITY		0x40
#define CREATE			0x80
#define DESTROY			0x100
#define UNMAP			0x200
#define MAP			0x400
#define REPARENT		0x800
#define CONFIG			0x1000
#define GRAVITY			0x2000
#define CIRC			0x4000
#define PROP			0x8000
#define COLORMAP		0x10000
#define VIRTUAL			0x20000
#define ACTIVATE		0x40000

#define KEY_BUTTON_MOTION_VIRTUAL	(KEY|BUTTON|MOTION|VIRTUAL)

static int flagArray[TK_LASTEVENT] = {
   /* Not used */		0,
   /* Not used */		0,
   /* KeyPress */		KEY,
   /* KeyRelease */		KEY,
   /* ButtonPress */		BUTTON,
   /* ButtonRelease */		BUTTON,
   /* MotionNotify */		MOTION,
   /* EnterNotify */		CROSSING,
   /* LeaveNotify */		CROSSING,
   /* FocusIn */		FOCUS,
   /* FocusOut */		FOCUS,
   /* KeymapNotify */		0,
   /* Expose */			EXPOSE,
   /* GraphicsExpose */		EXPOSE,
   /* NoExpose */		0,
   /* VisibilityNotify */	VISIBILITY,
   /* CreateNotify */		CREATE,
   /* DestroyNotify */		DESTROY,
   /* UnmapNotify */		UNMAP,
   /* MapNotify */		MAP,
   /* MapRequest */		0,
   /* ReparentNotify */		REPARENT,
   /* ConfigureNotify */	CONFIG,
   /* ConfigureRequest */	0,
   /* GravityNotify */		GRAVITY,
   /* ResizeRequest */		0,
   /* CirculateNotify */	CIRC,
   /* CirculateRequest */	0,
   /* PropertyNotify */		PROP,
   /* SelectionClear */		0,
   /* SelectionRequest */	0,
   /* SelectionNotify */	0,
   /* ColormapNotify */		COLORMAP,
   /* ClientMessage */		0,
   /* MappingNotify */		0,
   /* VirtualEvent */		VIRTUAL,
   /* Activate */		ACTIVATE,	    
   /* Deactivate */		ACTIVATE
};

/*
 * The following tables are used as a two-way map between X's internal
 * numeric values for fields in an XEvent and the strings used in Tcl.  The
 * tables are used both when constructing an XEvent from user input and
 * when providing data from an XEvent to the user.
 */

static TkStateMap notifyMode[] = {
    {NotifyNormal,	    "NotifyNormal"},
    {NotifyGrab,	    "NotifyGrab"},
    {NotifyUngrab,	    "NotifyUngrab"},
    {NotifyWhileGrabbed,    "NotifyWhileGrabbed"},
    {-1, NULL}
};

static TkStateMap notifyDetail[] = {
    {NotifyAncestor,	    "NotifyAncestor"},
    {NotifyVirtual,	    "NotifyVirtual"},
    {NotifyInferior,	    "NotifyInferior"},
    {NotifyNonlinear,	    "NotifyNonlinear"},
    {NotifyNonlinearVirtual,"NotifyNonlinearVirtual"},
    {NotifyPointer,	    "NotifyPointer"},
    {NotifyPointerRoot,	    "NotifyPointerRoot"},
    {NotifyDetailNone,	    "NotifyDetailNone"},
    {-1, NULL}
};

static TkStateMap circPlace[] = {
    {PlaceOnTop,    "PlaceOnTop"},
    {PlaceOnBottom, "PlaceOnBottom"},
    {-1, NULL}
};

static TkStateMap visNotify[] = {
    {VisibilityUnobscured,	    "VisibilityUnobscured"},
    {VisibilityPartiallyObscured,   "VisibilityPartiallyObscured"},
    {VisibilityFullyObscured,	    "VisibilityFullyObscured"},
    {-1, NULL}
};

/*
 * Prototypes for local procedures defined in this file:
 */

static void		ChangeScreen _ANSI_ARGS_((Tcl_Interp *interp,
			    char *dispName, int screenIndex));
static int		CreateVirtualEvent _ANSI_ARGS_((Tcl_Interp *interp,
			    TkVirtualEventTable *vetPtr, char *virtString,
			    char *eventString));
static TkVirtualEventTable *CreateVirtualEventTable _ANSI_ARGS_((void));
static int		DeleteVirtualEvent _ANSI_ARGS_((Tcl_Interp *interp,
			    TkVirtualEventTable *vetPtr, char *virtString,
			    char *eventString));
static void		DeleteVirtualEventTable _ANSI_ARGS_((
			    TkVirtualEventTable *vetPtr));
static void		ExpandPercents _ANSI_ARGS_((TkWindow *winPtr,
			    char *before, XEvent *eventPtr, KeySym keySym,
			    Tcl_DString *dsPtr));
static PatSeq *		FindSequence _ANSI_ARGS_((Tcl_Interp *interp,
			    Tcl_HashTable *patternTablePtr, ClientData object,
			    char *eventString, int create, int allowVirtual,
			    unsigned long *maskPtr));
static void		FreeScreenInfo _ANSI_ARGS_((ClientData clientData,
			    Tcl_Interp *interp));
static void		GetAllVirtualEvents _ANSI_ARGS_((Tcl_Interp *interp,
			    TkVirtualEventTable *vetPtr));
static char *		GetField _ANSI_ARGS_((char *p, char *copy, int size));
static KeySym		GetKeySym _ANSI_ARGS_((TkDisplay *dispPtr,
			    XEvent *eventPtr));
static void		GetPatternString _ANSI_ARGS_((PatSeq *psPtr,
			    Tcl_DString *dsPtr));
static int		GetVirtualEvent _ANSI_ARGS_((Tcl_Interp *interp,
			    TkVirtualEventTable *vetPtr, char *virtString));
static Tk_Uid		GetVirtualEventUid _ANSI_ARGS_((Tcl_Interp *interp,
			    char *virtString));
static int		HandleEventGenerate _ANSI_ARGS_((Tcl_Interp *interp,
			    Tk_Window tkwin, int argc, char **argv));
static void		InitKeymapInfo _ANSI_ARGS_((TkDisplay *dispPtr));
static PatSeq *		MatchPatterns _ANSI_ARGS_((TkDisplay *dispPtr,
			    BindingTable *bindPtr, PatSeq *psPtr,
			    PatSeq *bestPtr, ClientData object,
			    char **bestCommandPtr));
static int		ParseEventDescription _ANSI_ARGS_((Tcl_Interp *interp,
			    char **eventStringPtr, Pattern *patPtr,
			    unsigned long *eventMaskPtr));



/*
 *---------------------------------------------------------------------------
 *
 * TkBindInit --
 *
 *	This procedure is called when an application is created.  It
 *	initializes all the structures used by bindings and virtual
 *	events.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Memory allocated.
 *
 *---------------------------------------------------------------------------
 */

void
TkBindInit(mainPtr)
    TkMainInfo *mainPtr;	/* The newly created application. */
{
    if (sizeof(XEvent) < sizeof(XVirtualEvent)) {
	panic("TkBindInit: virtual events can't be supported");
    }
    mainPtr->bindingTable = Tk_CreateBindingTable(mainPtr->interp);
    mainPtr->vetPtr = CreateVirtualEventTable();
}

/*
 *---------------------------------------------------------------------------
 *
 * TkBindFree --
 *
 *	This procedure is called when an application is deleted.  It
 *	deletes all the structures used by bindings and virtual events.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Memory freed.
 *
 *---------------------------------------------------------------------------
 */

void
TkBindFree(mainPtr)
    TkMainInfo *mainPtr;	/* The newly created application. */
{
    Tk_DeleteBindingTable(mainPtr->bindingTable);
    mainPtr->bindingTable = NULL;
    
    DeleteVirtualEventTable(mainPtr->vetPtr);
    mainPtr->vetPtr = NULL;
}

/*
 *--------------------------------------------------------------
 *
 * Tk_CreateBindingTable --
 *
 *	Set up a new domain in which event bindings may be created.
 *
 * Results:
 *	The return value is a token for the new table, which must
 *	be passed to procedures like Tk_CreatBinding.
 *
 * Side effects:
 *	Memory is allocated for the new table.
 *
 *--------------------------------------------------------------
 */

Tk_BindingTable
Tk_CreateBindingTable(interp)
    Tcl_Interp *interp;		/* Interpreter to associate with the binding
				 * table:  commands are executed in this
				 * interpreter. */
{
    BindingTable *bindPtr;
    int i;

    /*
     * If this is the first time a binding table has been created,
     * initialize the global data structures.
     */

    if (!initialized) {
	Tcl_HashEntry *hPtr;
	ModInfo *modPtr;
	EventInfo *eiPtr;
	int dummy;

#ifdef REDO_KEYSYM_LOOKUP
	KeySymInfo *kPtr;

	Tcl_InitHashTable(&keySymTable, TCL_STRING_KEYS);
	Tcl_InitHashTable(&nameTable, TCL_ONE_WORD_KEYS);
	for (kPtr = keyArray; kPtr->name != NULL; kPtr++) {
	    hPtr = Tcl_CreateHashEntry(&keySymTable, kPtr->name, &dummy);
	    Tcl_SetHashValue(hPtr, kPtr->value);
	    hPtr = Tcl_CreateHashEntry(&nameTable, (char *) kPtr->value,
		    &dummy);
	    Tcl_SetHashValue(hPtr, kPtr->name);
	}
#endif /* REDO_KEYSYM_LOOKUP */

	initialized = 1;
    
	Tcl_InitHashTable(&modTable, TCL_STRING_KEYS);
	for (modPtr = modArray; modPtr->name != NULL; modPtr++) {
	    hPtr = Tcl_CreateHashEntry(&modTable, modPtr->name, &dummy);
	    Tcl_SetHashValue(hPtr, modPtr);
	}
    
	Tcl_InitHashTable(&eventTable, TCL_STRING_KEYS);
	for (eiPtr = eventArray; eiPtr->name != NULL; eiPtr++) {
	    hPtr = Tcl_CreateHashEntry(&eventTable, eiPtr->name, &dummy);
	    Tcl_SetHashValue(hPtr, eiPtr);
	}
    }

    /*
     * Create and initialize a new binding table.
     */

    bindPtr = (BindingTable *) ckalloc(sizeof(BindingTable));
    for (i = 0; i < EVENT_BUFFER_SIZE; i++) {
	bindPtr->eventRing[i].type = -1;
    }
    bindPtr->curEvent = 0;
    Tcl_InitHashTable(&bindPtr->patternTable,
	    sizeof(PatternTableKey)/sizeof(int));
    Tcl_InitHashTable(&bindPtr->objectTable, TCL_ONE_WORD_KEYS);
    bindPtr->interp = interp;
    return (Tk_BindingTable) bindPtr;
}

/*
 *--------------------------------------------------------------
 *
 * Tk_DeleteBindingTable --
 *
 *	Destroy a binding table and free up all its memory.
 *	The caller should not use bindingTable again after
 *	this procedure returns.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Memory is freed.
 *
 *--------------------------------------------------------------
 */

void
Tk_DeleteBindingTable(bindingTable)
    Tk_BindingTable bindingTable;	/* Token for the binding table to
					 * destroy. */
{
    BindingTable *bindPtr = (BindingTable *) bindingTable;
    PatSeq *psPtr, *nextPtr;
    Tcl_HashEntry *hPtr;
    Tcl_HashSearch search;

    /*
     * Find and delete all of the patterns associated with the binding
     * table.
     */

    for (hPtr = Tcl_FirstHashEntry(&bindPtr->patternTable, &search);
	    hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
	for (psPtr = (PatSeq *) Tcl_GetHashValue(hPtr);
		psPtr != NULL; psPtr = nextPtr) {
	    nextPtr = psPtr->nextSeqPtr;
	    ckfree((char *) psPtr->command);
	    ckfree((char *) psPtr);
	}
    }

    /*
     * Clean up the rest of the information associated with the
     * binding table.
     */

    Tcl_DeleteHashTable(&bindPtr->patternTable);
    Tcl_DeleteHashTable(&bindPtr->objectTable);
    ckfree((char *) bindPtr);
}

/*
 *--------------------------------------------------------------
 *
 * Tk_CreateBinding --
 *
 *	Add a binding to a binding table, so that future calls to
 *	Tk_BindEvent may execute the command in the binding.
 *
 * Results:
 *	The return value is 0 if an error occurred while setting
 *	up the binding.  In this case, an error message will be
 *	left in interp->result.  If all went well then the return
 *	value is a mask of the event types that must be made
 *	available to Tk_BindEvent in order to properly detect when
 *	this binding triggers.  This value can be used to determine
 *	what events to select for in a window, for example.
 *
 * Side effects:
 *	The new binding may cause future calls to Tk_BindEvent to
 *	behave differently than they did previously.
 *
 *--------------------------------------------------------------
 */

unsigned long
Tk_CreateBinding(interp, bindingTable, object, eventString, command, append)
    Tcl_Interp *interp;			/* Used for error reporting. */
    Tk_BindingTable bindingTable;	/* Table in which to create binding. */
    ClientData object;			/* Token for object with which binding
					 * is associated. */
    char *eventString;			/* String describing event sequence
					 * that triggers binding. */
    char *command;			/* Contains Tcl command to execute
					 * when binding triggers. */
    int append;				/* 0 means replace any existing
					 * binding for eventString;  1 means
					 * append to that binding. */
{
    BindingTable *bindPtr = (BindingTable *) bindingTable;
    PatSeq *psPtr;
    unsigned long eventMask;

    psPtr = FindSequence(interp, &bindPtr->patternTable, object, eventString,
	    1, 1, &eventMask);
    if (psPtr == NULL) {
	return 0;
    }
    if (psPtr->command == NULL) {
	int new;
	Tcl_HashEntry *hPtr;
	
	/*
	 * This pattern sequence was just created.
	 * Link the pattern into the list associated with the object.
	 */

	hPtr = Tcl_CreateHashEntry(&bindPtr->objectTable, (char *) object,
		&new);
	if (new) {
	    psPtr->nextObjPtr = NULL;
	} else {
	    psPtr->nextObjPtr = (PatSeq *) Tcl_GetHashValue(hPtr);
	}
	Tcl_SetHashValue(hPtr, psPtr);
    }

    if (append && (psPtr->command != NULL)) {
	int length;
	char *new;

	length = strlen(psPtr->command) + strlen(command) + 2;
	new = (char *) ckalloc((unsigned) length);
	sprintf(new, "%s\n%s", psPtr->command, command);
	ckfree((char *) psPtr->command);
	psPtr->command = new;
    } else {
	if (psPtr->command != NULL) {
	    ckfree((char *) psPtr->command);
	}
	psPtr->command = (char *) ckalloc((unsigned) (strlen(command) + 1));
	strcpy(psPtr->command, command);
    }
    return eventMask;
}

/*
 *--------------------------------------------------------------
 *
 * Tk_DeleteBinding --
 *
 *	Remove an event binding from a binding table.
 *
 * Results:
 *	The result is a standard Tcl return value.  If an error
 *	occurs then interp->result will contain an error message.
 *
 * Side effects:
 *	The binding given by object and eventString is removed
 *	from bindingTable.
 *
 *--------------------------------------------------------------
 */

int
Tk_DeleteBinding(interp, bindingTable, object, eventString)
    Tcl_Interp *interp;			/* Used for error reporting. */
    Tk_BindingTable bindingTable;	/* Table in which to delete binding. */
    ClientData object;			/* Token for object with which binding
					 * is associated. */
    char *eventString;			/* String describing event sequence
					 * that triggers binding. */
{
    BindingTable *bindPtr = (BindingTable *) bindingTable;
    PatSeq *psPtr, *prevPtr;
    unsigned long eventMask;
    Tcl_HashEntry *hPtr;

    psPtr = FindSequence(interp, &bindPtr->patternTable, object, eventString,
	    0, 1, &eventMask);
    if (psPtr == NULL) {
	Tcl_ResetResult(interp);
	return TCL_OK;
    }

    /*
     * Unlink the binding from the list for its object, then from the
     * list for its pattern.
     */

    hPtr = Tcl_FindHashEntry(&bindPtr->objectTable, (char *) object);
    if (hPtr == NULL) {
	panic("Tk_DeleteBinding couldn't find object table entry");
    }
    prevPtr = (PatSeq *) Tcl_GetHashValue(hPtr);
    if (prevPtr == psPtr) {
	Tcl_SetHashValue(hPtr, psPtr->nextObjPtr);
    } else {
	for ( ; ; prevPtr = prevPtr->nextObjPtr) {
	    if (prevPtr == NULL) {
		panic("Tk_DeleteBinding couldn't find on object list");
	    }
	    if (prevPtr->nextObjPtr == psPtr) {
		prevPtr->nextObjPtr = psPtr->nextObjPtr;
		break;
	    }
	}
    }
    prevPtr = (PatSeq *) Tcl_GetHashValue(psPtr->hPtr);
    if (prevPtr == psPtr) {
	if (psPtr->nextSeqPtr == NULL) {
	    Tcl_DeleteHashEntry(psPtr->hPtr);
	} else {
	    Tcl_SetHashValue(psPtr->hPtr, psPtr->nextSeqPtr);
	}
    } else {
	for ( ; ; prevPtr = prevPtr->nextSeqPtr) {
	    if (prevPtr == NULL) {
		panic("Tk_DeleteBinding couldn't find on hash chain");
	    }
	    if (prevPtr->nextSeqPtr == psPtr) {
		prevPtr->nextSeqPtr = psPtr->nextSeqPtr;
		break;
	    }
	}
    }
    ckfree((char *) psPtr->command);
    ckfree((char *) psPtr);
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * Tk_GetBinding --
 *
 *	Return the command associated with a given event string.
 *
 * Results:
 *	The return value is a pointer to the command string
 *	associated with eventString for object in the domain
 *	given by bindingTable.  If there is no binding for
 *	eventString, or if eventString is improperly formed,
 *	then NULL is returned and an error message is left in
 *	interp->result.  The return value is semi-static:  it
 *	will persist until the binding is changed or deleted.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

char *
Tk_GetBinding(interp, bindingTable, object, eventString)
    Tcl_Interp *interp;			/* Interpreter for error reporting. */
    Tk_BindingTable bindingTable;	/* Table in which to look for
					 * binding. */
    ClientData object;			/* Token for object with which binding
					 * is associated. */
    char *eventString;			/* String describing event sequence
					 * that triggers binding. */
{
    BindingTable *bindPtr = (BindingTable *) bindingTable;
    PatSeq *psPtr;
    unsigned long eventMask;

    psPtr = FindSequence(interp, &bindPtr->patternTable, object, eventString,
	    0, 1, &eventMask);
    if (psPtr == NULL) {
	return NULL;
    }
    return psPtr->command;
}

/*
 *--------------------------------------------------------------
 *
 * Tk_GetAllBindings --
 *
 *	Return a list of event strings for all the bindings
 *	associated with a given object.
 *
 * Results:
 *	There is no return value.  Interp->result is modified to
 *	hold a Tcl list with one entry for each binding associated
 *	with object in bindingTable.  Each entry in the list
 *	contains the event string associated with one binding.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

void
Tk_GetAllBindings(interp, bindingTable, object)
    Tcl_Interp *interp;			/* Interpreter returning result or
					 * error. */
    Tk_BindingTable bindingTable;	/* Table in which to look for
					 * bindings. */
    ClientData object;			/* Token for object. */

{
    BindingTable *bindPtr = (BindingTable *) bindingTable;
    PatSeq *psPtr;
    Tcl_HashEntry *hPtr;
    Tcl_DString ds;

    hPtr = Tcl_FindHashEntry(&bindPtr->objectTable, (char *) object);
    if (hPtr == NULL) {
	return;
    }
    Tcl_DStringInit(&ds);
    for (psPtr = (PatSeq *) Tcl_GetHashValue(hPtr); psPtr != NULL;
	    psPtr = psPtr->nextObjPtr) {
	/* 
	 * For each binding, output information about each of the
	 * patterns in its sequence.
	 */
	 
	Tcl_DStringSetLength(&ds, 0);
	GetPatternString(psPtr, &ds);
	Tcl_AppendElement(interp, Tcl_DStringValue(&ds));
    }
    Tcl_DStringFree(&ds);
}

/*
 *--------------------------------------------------------------
 *
 * Tk_DeleteAllBindings --
 *
 *	Remove all bindings associated with a given object in a
 *	given binding table.
 *
 * Results:
 *	All bindings associated with object are removed from
 *	bindingTable.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

void
Tk_DeleteAllBindings(bindingTable, object)
    Tk_BindingTable bindingTable;	/* Table in which to delete
					 * bindings. */
    ClientData object;			/* Token for object. */
{
    BindingTable *bindPtr = (BindingTable *) bindingTable;
    PatSeq *psPtr, *prevPtr;
    PatSeq *nextPtr;
    Tcl_HashEntry *hPtr;

    hPtr = Tcl_FindHashEntry(&bindPtr->objectTable, (char *) object);
    if (hPtr == NULL) {
	return;
    }
    for (psPtr = (PatSeq *) Tcl_GetHashValue(hPtr); psPtr != NULL;
	    psPtr = nextPtr) {
	nextPtr  = psPtr->nextObjPtr;

	/*
	 * Be sure to remove each binding from its hash chain in the
	 * pattern table.  If this is the last pattern in the chain,
	 * then delete the hash entry too.
	 */

	prevPtr = (PatSeq *) Tcl_GetHashValue(psPtr->hPtr);
	if (prevPtr == psPtr) {
	    if (psPtr->nextSeqPtr == NULL) {
		Tcl_DeleteHashEntry(psPtr->hPtr);
	    } else {
		Tcl_SetHashValue(psPtr->hPtr, psPtr->nextSeqPtr);
	    }
	} else {
	    for ( ; ; prevPtr = prevPtr->nextSeqPtr) {
		if (prevPtr == NULL) {
		    panic("Tk_DeleteAllBindings couldn't find on hash chain");
		}
		if (prevPtr->nextSeqPtr == psPtr) {
		    prevPtr->nextSeqPtr = psPtr->nextSeqPtr;
		    break;
		}
	    }
	}
	ckfree((char *) psPtr->command);
	ckfree((char *) psPtr);
    }
    Tcl_DeleteHashEntry(hPtr);
}

/*
 *--------------------------------------------------------------
 *
 * Tk_BindEvent --
 *
 *	This procedure is invoked to process an X event.  The
 *	event is added to those recorded for the binding table.
 *	Then each of the objects at *objectPtr is checked in
 *	order to see if it has a binding that matches the recent
 *	events.  If so, the most specific binding is invoked for
 *	each object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Depends on the command associated with the matching
 *	binding.
 *
 *--------------------------------------------------------------
 */

void
Tk_BindEvent(bindingTable, eventPtr, tkwin, numObjects, objectPtr)
    Tk_BindingTable bindingTable;	/* Table in which to look for
					 * bindings. */
    XEvent *eventPtr;			/* What actually happened. */
    Tk_Window tkwin;			/* Window on display where event
					 * occurred (needed in order to
					 * locate display information). */
    int numObjects;			/* Number of objects at *objectPtr. */
    ClientData *objectPtr;		/* Array of one or more objects
					 * to check for a matching binding. */
{
    BindingTable *bindPtr = (BindingTable *) bindingTable;
    TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr;
    TkDisplay *oldDispPtr;
    ScreenInfo *screenPtr;
    XEvent *ringPtr;
    PatSeq *vMatchDetailList, *vMatchNoDetailList;
    PatternTableKey key;
    Tcl_HashEntry *hPtr;
    int flags, code, oldScreen;
    Tcl_Interp *interp;
    Tcl_DString scripts, savedResult;
    char *p, *end;
    Detail detail;

    /*
     * Ignore the event completely if it is an Enter, Leave, FocusIn,
     * or FocusOut event with detail NotifyInferior.  The reason for
     * ignoring these events is that we don't want transitions between
     * a window and its children to visible to bindings on the parent:
     * this would cause problems for mega-widgets, since the internal
     * structure of a mega-widget isn't supposed to be visible to
     * people watching the parent.
     */

    if ((eventPtr->type == EnterNotify)  || (eventPtr->type == LeaveNotify)) {
	if (eventPtr->xcrossing.detail == NotifyInferior) {
	    return;
	}
    }
    if ((eventPtr->type == FocusIn)  || (eventPtr->type == FocusOut)) {
	if (eventPtr->xfocus.detail == NotifyInferior) {
	    return;
	}
    }

    /*
     * Add the new event to the ring of saved events for the
     * binding table.  Two tricky points:
     *
     * 1. Combine consecutive MotionNotify events.  Do this by putting
     *    the new event *on top* of the previous event.
     * 2. If a modifier key is held down, it auto-repeats to generate
     *    continuous KeyPress and KeyRelease events.  These can flush
     *    the event ring so that valuable information is lost (such
     *    as repeated button clicks).  To handle this, check for the
     *    special case of a modifier KeyPress arriving when the previous
     *    two events are a KeyRelease and KeyPress of the same key.
     *    If this happens, mark the most recent event (the KeyRelease)
     *    invalid and put the new event on top of the event before that
     *    (the KeyPress).
     */

    if ((eventPtr->type == MotionNotify)
	    && (bindPtr->eventRing[bindPtr->curEvent].type == MotionNotify)) {
	/*
	 * Don't advance the ring pointer.
	 */
    } else if (eventPtr->type == KeyPress) {
	int i;
	for (i = 0; ; i++) {
	    if (i >= dispPtr->numModKeyCodes) {
		goto advanceRingPointer;
	    }
	    if (dispPtr->modKeyCodes[i] == eventPtr->xkey.keycode) {
		break;
	    }
	}
	ringPtr = &bindPtr->eventRing[bindPtr->curEvent];
	if ((ringPtr->type != KeyRelease)
		|| (ringPtr->xkey.keycode != eventPtr->xkey.keycode)) {
	    goto advanceRingPointer;
	}
	if (bindPtr->curEvent <= 0) {
	    i = EVENT_BUFFER_SIZE - 1;
	} else {
	    i = bindPtr->curEvent - 1;
	}
	ringPtr = &bindPtr->eventRing[i];
	if ((ringPtr->type != KeyPress)
		|| (ringPtr->xkey.keycode != eventPtr->xkey.keycode)) {
	    goto advanceRingPointer;
	}
	bindPtr->eventRing[bindPtr->curEvent].type = -1;
	bindPtr->curEvent = i;
    } else {
	advanceRingPointer:
	bindPtr->curEvent++;
	if (bindPtr->curEvent >= EVENT_BUFFER_SIZE) {
	    bindPtr->curEvent = 0;
	}
    }
    ringPtr = &bindPtr->eventRing[bindPtr->curEvent];
    memcpy((VOID *) ringPtr, (VOID *) eventPtr, sizeof(XEvent));
    detail.clientData = 0;
    flags = flagArray[ringPtr->type];
    if (flags & KEY) {
	detail.keySym = GetKeySym(dispPtr, ringPtr);
	if (detail.keySym == NoSymbol) {
	    detail.keySym = 0;
	}
    } else if (flags & BUTTON) {
	detail.button = ringPtr->xbutton.button;
    } else if (flags & VIRTUAL) {
	detail.name = ((XVirtualEvent *) ringPtr)->name;
    }
    bindPtr->detailRing[bindPtr->curEvent] = detail;

    /*
     * Find out if there are any virtual events that correspond to this
     * physical event (or sequence of physical events).
     */

    vMatchDetailList = NULL;
    vMatchNoDetailList = NULL;
    memset(&key, 0, sizeof(key));

    if (ringPtr->type != VirtualEvent) {
	TkWindow *winPtr = (TkWindow *) tkwin;
	Tcl_HashTable *veptPtr = &winPtr->mainPtr->vetPtr->patternTable;

        key.object  = NULL;
	key.type    = ringPtr->type;
	key.detail  = detail;

	hPtr = Tcl_FindHashEntry(veptPtr, (char *) &key);
	if (hPtr != NULL) {
	    vMatchDetailList = (PatSeq *) Tcl_GetHashValue(hPtr);
	}

	if (key.detail.clientData != 0) {
	    key.detail.clientData = 0;
	    hPtr = Tcl_FindHashEntry(veptPtr, (char *) &key);
	    if (hPtr != NULL) {
	        vMatchNoDetailList = (PatSeq *) Tcl_GetHashValue(hPtr);
	    }
	}
    }

    /*
     * Loop over all the objects, finding the binding script for each
     * one.  Append all of the binding scripts, with %-sequences expanded,
     * to "scripts", with null characters separating the scripts for
     * each object.
     */

    Tcl_DStringInit(&scripts);
    for ( ; numObjects > 0; numObjects--, objectPtr++) {
	PatSeq *matchPtr;
	char *command;

	matchPtr = NULL;
	command = NULL;

	/*
	 * Match the new event against those recorded in the pattern table,
	 * saving the longest matching pattern.  For events with details
	 * (button and key events), look for a binding for the specific
	 * key or button.  First see if the event matches a physical event
	 * that the object is interested in, then look for a virtual event.
	 */

	key.object = *objectPtr;
	key.type = ringPtr->type;
	key.detail = detail;
	hPtr = Tcl_FindHashEntry(&bindPtr->patternTable, (char *) &key);
	if (hPtr != NULL) {
	    matchPtr = MatchPatterns(dispPtr, bindPtr, 
		    (PatSeq *) Tcl_GetHashValue(hPtr), matchPtr, NULL,
		    &command);
	}

	if (vMatchDetailList != NULL) {
	    matchPtr = MatchPatterns(dispPtr, bindPtr, vMatchDetailList,
		    matchPtr, *objectPtr, &command);
	}


	/*
	 * If no match was found, look for a binding for all keys or buttons
	 * (detail of 0).  Again, first match on a virtual event.
	 */

	if ((detail.clientData != 0) && (matchPtr == NULL)) {
	    key.detail.clientData = 0;
	    hPtr = Tcl_FindHashEntry(&bindPtr->patternTable, (char *) &key);
	    if (hPtr != NULL) {
		matchPtr = MatchPatterns(dispPtr, bindPtr,
			(PatSeq *) Tcl_GetHashValue(hPtr), matchPtr, NULL,
			&command);
	    }

	    if (vMatchNoDetailList != NULL) {
	        matchPtr = MatchPatterns(dispPtr, bindPtr, vMatchNoDetailList,
			matchPtr, *objectPtr, &command);
	    }

	}
    
	if (matchPtr != NULL) {
	    if (command == NULL) {
		panic("Tk_BindEvent: missing command");
	    }
	    ExpandPercents((TkWindow *) tkwin, command, eventPtr,
		    detail.keySym, &scripts);
	    Tcl_DStringAppend(&scripts, "", 1);
	}
    }
    if (Tcl_DStringLength(&scripts) == 0) {
	return;
    }

    /*
     * Now go back through and evaluate the script for each object,
     * in order, dealing with "break" and "continue" exceptions
     * appropriately.
     *
     * There are two tricks here:
     * 1. Bindings can be invoked from in the middle of Tcl commands,
     *    where interp->result is significant (for example, a widget
     *    might be deleted because of an error in creating it, so the
     *    result contains an error message that is eventually going to
     *    be returned by the creating command).  To preserve the result,
     *    we save it in a dynamic string.
     * 2. The binding's action can potentially delete the binding,
     *    so bindPtr may not point to anything valid once the action
     *    completes.  Thus we have to save bindPtr->interp in a
     *    local variable in order to restore the result.
     */

    interp = bindPtr->interp;
    Tcl_DStringInit(&savedResult);

    /*
     * Save information about the current screen, then invoke a script
     * if the screen has changed.
     */

    Tcl_DStringGetResult(interp, &savedResult);
    screenPtr = (ScreenInfo *) Tcl_GetAssocData(interp, "tkBind",
	    (Tcl_InterpDeleteProc **) NULL);
    if (screenPtr == NULL) {
	screenPtr = (ScreenInfo *) ckalloc(sizeof(ScreenInfo));
	screenPtr->curDispPtr = NULL;
	screenPtr->curScreenIndex = -1;
	screenPtr->bindingDepth = 0;
	Tcl_SetAssocData(interp, "tkBind", FreeScreenInfo,
		(ClientData) screenPtr);
    }
    oldDispPtr = screenPtr->curDispPtr;
    oldScreen = screenPtr->curScreenIndex;
    if ((dispPtr != screenPtr->curDispPtr)
	    || (Tk_ScreenNumber(tkwin) != screenPtr->curScreenIndex)) {
	screenPtr->curDispPtr = dispPtr;
	screenPtr->curScreenIndex = Tk_ScreenNumber(tkwin);
	ChangeScreen(interp, dispPtr->name, screenPtr->curScreenIndex);
    }

    p = Tcl_DStringValue(&scripts);
    end = p + Tcl_DStringLength(&scripts);
    while (p != end) {
	screenPtr->bindingDepth += 1;
	Tcl_AllowExceptions(interp);
	code = Tcl_GlobalEval(interp, p);
	screenPtr->bindingDepth -= 1;
	if (code != TCL_OK) {
	    if (code == TCL_CONTINUE) {
		/*
		 * Do nothing:  just go on to the next script.
		 */
	    } else if (code == TCL_BREAK) {
		break;
	    } else {
		Tcl_AddErrorInfo(interp, "\n    (command bound to event)");
		Tcl_BackgroundError(interp);
		break;
	    }
	}

	/*
	 * Skip over the current script and its terminating null character.
	 */

	while (*p != 0) {
	    p++;
	}
	p++;
    }
    if ((screenPtr->bindingDepth != 0) &&
            ((oldDispPtr != screenPtr->curDispPtr)
                    || (oldScreen != screenPtr->curScreenIndex))) {

	/*
	 * Some other binding script is currently executing, but its
	 * screen is no longer current.  Change the current display
	 * back again.
	 */

	screenPtr->curDispPtr = oldDispPtr;
	screenPtr->curScreenIndex = oldScreen;
	ChangeScreen(interp, oldDispPtr->name, oldScreen);
    }
    Tcl_DStringResult(interp, &savedResult);
    Tcl_DStringFree(&scripts);
}

/*
 *----------------------------------------------------------------------
 *
 * MatchPatterns --
 *
 *      Given a list of pattern sequences and a list of recent events,
 *      return the pattern sequence that best matches the event list,
 *	if there is one.
 *
 *	This procedure is used in two different ways.  In the simplest
 *	use, "object" is NULL and psPtr is a list of pattern sequences,
 *	each of which corresponds to a binding.  In this case, the
 *	procedure finds the pattern sequences that match the event list
 *	and returns the most specify of those, if there is more than one.
 *
 *	In the second case, psPtr is a list of pattern sequences, each
 *	of which corresponds to a definition for a virtual binding.
 *	In order for one of these sequences to "match", it must match
 *	the events (as above) but in addition there must be a binding
 *	for its associated virtual event on the current object.  The
 *	"object" argument indicates which object the binding must be for.
 *
 * Results:
 *      The return value is NULL if bestPtr is NULL and no pattern matches
 *	the recent events from bindPtr.  Otherwise the return value is
 *	the most specific pattern sequence among bestPtr and all those
 *	at psPtr that match the event list and object.  If a pattern
 *	sequence other than bestPtr is returned, then *bestCommandPtr
 *	is filled in with a pointer to the command from the best sequence.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */
static PatSeq *
MatchPatterns(dispPtr, bindPtr, psPtr, bestPtr, object, bestCommandPtr)
    TkDisplay *dispPtr;		/* Display from which the event came. */
    BindingTable *bindPtr;	/* Information about binding table, such as
				 * ring of recent events. */
    PatSeq *psPtr;		/* List of pattern sequences. */
    PatSeq *bestPtr; 		/* The best match seen so far, from a
				 * previous call to this procedure.  NULL
				 * means no prior best match. */
    ClientData object;		/* If NULL, the sequences at psPtr
				 * correspond to "normal" bindings.  If
				 * non-NULL, the sequences at psPtr correspond
				 * to virtual bindings; in order to match each
				 * sequence must correspond to a virtual
				 * binding for which a binding exists for
				 * object in bindPtr. */
    char **bestCommandPtr;      /* Returns the command associated with the
				 * best match.  Not modified unless a result
				 * other than bestPtr is returned. */
{
    PatSeq *matchPtr;
    char *bestCommand, *command;

    bestCommand = *bestCommandPtr;

    /*
     * Iterate over all the pattern sequences.
     */

    for ( ; psPtr != NULL; psPtr = psPtr->nextSeqPtr) {
	XEvent *eventPtr;
	Pattern *patPtr;
	Window window;
	Detail *detailPtr;
	int patCount, ringCount, flags, state;
	int modMask;

	/*
	 * Iterate over all the patterns in a sequence to be
	 * sure that they all match.
	 */

	eventPtr = &bindPtr->eventRing[bindPtr->curEvent];
	detailPtr = &bindPtr->detailRing[bindPtr->curEvent];
	window = eventPtr->xany.window;
	patPtr = psPtr->pats;
	patCount = psPtr->numPats;
	ringCount = EVENT_BUFFER_SIZE;
	while (patCount > 0) {
	    if (ringCount <= 0) {
		goto nextSequence;
	    }
	    if (eventPtr->xany.type != patPtr->eventType) {
		/*
		 * Most of the event types are considered superfluous
		 * in that they are ignored if they occur in the middle
		 * of a pattern sequence and have mismatching types.  The
		 * only ones that cannot be ignored are ButtonPress and
		 * ButtonRelease events (if the next event in the pattern
		 * is a KeyPress or KeyRelease) and KeyPress and KeyRelease
		 * events (if the next pattern event is a ButtonPress or
		 * ButtonRelease).  Here are some tricky cases to consider:
		 * 1. Double-Button or Double-Key events.
		 * 2. Double-ButtonRelease or Double-KeyRelease events.
		 * 3. The arrival of various events like Enter and Leave
		 *    and FocusIn and GraphicsExpose between two button
		 *    presses or key presses.
		 * 4. Modifier keys like Shift and Control shouldn't
		 *    generate conflicts with button events.
		 */

		if ((patPtr->eventType == KeyPress)
			|| (patPtr->eventType == KeyRelease)) {
		    if ((eventPtr->xany.type == ButtonPress)
			    || (eventPtr->xany.type == ButtonRelease)) {
			goto nextSequence;
		    }
		} else if ((patPtr->eventType == ButtonPress)
			|| (patPtr->eventType == ButtonRelease)) {
		    if ((eventPtr->xany.type == KeyPress)
			    || (eventPtr->xany.type == KeyRelease)) {
			int i;

			/*
			 * Ignore key events if they are modifier keys.
			 */

			for (i = 0; i < dispPtr->numModKeyCodes; i++) {
			    if (dispPtr->modKeyCodes[i]
				    == eventPtr->xkey.keycode) {
				/*
				 * This key is a modifier key, so ignore it.
				 */
				goto nextEvent;
			    }
			}
			goto nextSequence;
		    }
		}
		goto nextEvent;
	    }
	    if (eventPtr->xany.window != window) {
		goto nextSequence;
	    }

	    /*
	     * Note: it's important for the keysym check to go before
	     * the modifier check, so we can ignore unwanted modifier
	     * keys before choking on the modifier check.
	     */

	    if ((patPtr->detail.clientData != 0)
		    && (patPtr->detail.clientData != detailPtr->clientData)) {
		/*
		 * The detail appears not to match.  However, if the event
		 * is a KeyPress for a modifier key then just ignore the
		 * event.  Otherwise event sequences like "aD" never match
		 * because the shift key goes down between the "a" and the
		 * "D".
		 */

		if (eventPtr->xany.type == KeyPress) {
		    int i;

		    for (i = 0; i < dispPtr->numModKeyCodes; i++) {
			if (dispPtr->modKeyCodes[i] == eventPtr->xkey.keycode) {
			    goto nextEvent;
			}
		    }
		}
		goto nextSequence;
	    }
	    flags = flagArray[eventPtr->type];
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL)) {
		state = eventPtr->xkey.state;
	    } else if (flags & CROSSING) {
		state = eventPtr->xcrossing.state;
	    } else {
		state = 0;
	    }
	    if (patPtr->needMods != 0) {
		modMask = patPtr->needMods;
		if ((modMask & META_MASK) && (dispPtr->metaModMask != 0)) {
		    modMask = (modMask & ~META_MASK) | dispPtr->metaModMask;
		}
		if ((modMask & ALT_MASK) && (dispPtr->altModMask != 0)) {
		    modMask = (modMask & ~ALT_MASK) | dispPtr->altModMask;
		}
		if ((state & modMask) != modMask) {
		    goto nextSequence;
		}
	    }
	    if (psPtr->flags & PAT_NEARBY) {
		XEvent *firstPtr;
		int timeDiff;

		firstPtr = &bindPtr->eventRing[bindPtr->curEvent];
		timeDiff = (Time) firstPtr->xkey.time - eventPtr->xkey.time;
		if ((firstPtr->xkey.x_root
			    < (eventPtr->xkey.x_root - NEARBY_PIXELS))
			|| (firstPtr->xkey.x_root
			    > (eventPtr->xkey.x_root + NEARBY_PIXELS))
			|| (firstPtr->xkey.y_root
			    < (eventPtr->xkey.y_root - NEARBY_PIXELS))
			|| (firstPtr->xkey.y_root
			    > (eventPtr->xkey.y_root + NEARBY_PIXELS))
			|| (timeDiff > NEARBY_MS)) {
		    goto nextSequence;
		}
	    }
	    patPtr++;
	    patCount--;
	    nextEvent:
	    if (eventPtr == bindPtr->eventRing) {
		eventPtr = &bindPtr->eventRing[EVENT_BUFFER_SIZE-1];
		detailPtr = &bindPtr->detailRing[EVENT_BUFFER_SIZE-1];
	    } else {
		eventPtr--;
		detailPtr--;
	    }
	    ringCount--;
	}

	matchPtr = psPtr;
	command = matchPtr->command;

	if (object != NULL) {
	    int iVirt;
	    VirtualOwners *voPtr;
	    PatternTableKey key;

	    /*
	     * The sequence matches the physical constraints.
	     * Is this object interested in any of the virtual events
	     * that correspond to this sequence?  
	     */

	    voPtr = psPtr->voPtr;

	    memset(&key, 0, sizeof(key));
	    key.object = object;
	    key.type = VirtualEvent;
	    key.detail.clientData = 0;

	    for (iVirt = 0; iVirt < voPtr->numOwners; iVirt++) {
	        Tcl_HashEntry *hPtr = voPtr->owners[iVirt];

	        key.detail.name = (Tk_Uid) Tcl_GetHashKey(hPtr->tablePtr,
			hPtr);
		hPtr = Tcl_FindHashEntry(&bindPtr->patternTable,
			(char *) &key);
		if (hPtr != NULL) {

		    /*
		     * This tag is interested in this virtual event and its
		     * corresponding physical event is a good match with the
		     * virtual event's definition.
		     */

		    PatSeq *virtMatchPtr;

		    virtMatchPtr = (PatSeq *) Tcl_GetHashValue(hPtr);
		    if ((virtMatchPtr->numPats != 1)
			    || (virtMatchPtr->nextSeqPtr != NULL)) {
			panic("MatchPattern: badly constructed virtual event");
		    }
		    command = virtMatchPtr->command;

		    goto match;
		}
	    }

	    /*
	     * The physical event matches a virtual event's definition, but
	     * the tag isn't interested in it.
	     */
	    goto nextSequence;
	}
	match:

	/*
	 * This sequence matches.  If we've already got another match,
	 * pick whichever is most specific.  Detail is most important,
	 * then needMods.
	 */

	if (bestPtr != NULL) {
	    Pattern *patPtr2;
	    int i;

	    if (matchPtr->numPats != bestPtr->numPats) {
		if (bestPtr->numPats > matchPtr->numPats) {
		    goto nextSequence;
		} else {
		    goto newBest;
		}
	    }
	    for (i = 0, patPtr = matchPtr->pats, patPtr2 = bestPtr->pats;
		    i < matchPtr->numPats; i++, patPtr++, patPtr2++) {
		if (patPtr->detail.clientData != patPtr2->detail.clientData) {
		    if (patPtr->detail.clientData == 0) {
			goto nextSequence;
		    } else {
			goto newBest;
		    }
		}
		if (patPtr->needMods != patPtr2->needMods) {
		    if ((patPtr->needMods & patPtr2->needMods)
			    == patPtr->needMods) {
			goto nextSequence;
		    } else if ((patPtr->needMods & patPtr2->needMods)
			    == patPtr2->needMods) {
			goto newBest;
		    }
		}
	    }
	    /*
	     * Tie goes to current best pattern.
	     *
	     * (1) For virtual vs. virtual, the least recently defined
	     * virtual wins, because virtuals are examined in order of
	     * definition.  This order is _not_ guaranteed in the
	     * documentation.
	     *
	     * (2) For virtual vs. physical, the physical wins because all
	     * the physicals are examined before the virtuals.  This order
	     * is guaranteed in the documentation.
	     *
	     * (3) For physical vs. physical pattern, the most recently
	     * defined physical wins, because physicals are examined in
	     * reverse order of definition.  This order is guaranteed in
	     * the documentation.
	     */

	    goto nextSequence;	
	}
	newBest:
	bestPtr = matchPtr;
	bestCommand = command;

	nextSequence: continue;
    }

    *bestCommandPtr = bestCommand;
    return bestPtr;
}

/*
 *--------------------------------------------------------------
 *
 * ExpandPercents --
 *
 *	Given a command and an event, produce a new command
 *	by replacing % constructs in the original command
 *	with information from the X event.
 *
 * Results:
 *	The new expanded command is appended to the dynamic string
 *	given by dsPtr.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static void
ExpandPercents(winPtr, before, eventPtr, keySym, dsPtr)
    TkWindow *winPtr;		/* Window where event occurred:  needed to
				 * get input context. */
    char *before;		/* Command containing percent expressions
				 * to be replaced. */
    XEvent *eventPtr;		/* X event containing information to be
				 * used in % replacements. */
    KeySym keySym;		/* KeySym: only relevant for KeyPress and
				 * KeyRelease events). */
    Tcl_DString *dsPtr;		/* Dynamic string in which to append new
				 * command. */
{
    int spaceNeeded, cvtFlags;	/* Used to substitute string as proper Tcl
				 * list element. */
    int number, flags, length;
#define NUM_SIZE 40
    char *string;
    char numStorage[NUM_SIZE+1];

    if (eventPtr->type < TK_LASTEVENT) {
	flags = flagArray[eventPtr->type];
    } else {
	flags = 0;
    }
    while (1) {
	/*
	 * Find everything up to the next % character and append it
	 * to the result string.
	 */

	for (string = before; (*string != 0) && (*string != '%'); string++) {
	    /* Empty loop body. */
	}
	if (string != before) {
	    Tcl_DStringAppend(dsPtr, before, string-before);
	    before = string;
	}
	if (*before == 0) {
	    break;
	}

	/*
	 * There's a percent sequence here.  Process it.
	 */

	number = 0;
	string = "??";
	switch (before[1]) {
	    case '#':
		number = eventPtr->xany.serial;
		goto doNumber;
	    case 'a':
		sprintf(numStorage, "0x%x", (int) eventPtr->xconfigure.above);
		string = numStorage;
		goto doString;
	    case 'b':
		number = eventPtr->xbutton.button;
		goto doNumber;
	    case 'c':
		if (flags & EXPOSE) {
		    number = eventPtr->xexpose.count;
		}
		goto doNumber;
	    case 'd':
		if (flags & (CROSSING|FOCUS)) {
		    if (flags & FOCUS) {
			number = eventPtr->xfocus.detail;
		    } else {
			number = eventPtr->xcrossing.detail;
		    }
		    string = TkFindStateString(notifyDetail, number);
		}
		goto doString;
	    case 'f':
		number = eventPtr->xcrossing.focus;
		goto doNumber;
	    case 'h':
		if (flags & EXPOSE) {
		    number = eventPtr->xexpose.height;
		} else if (flags & (CONFIG)) {
		    number = eventPtr->xconfigure.height;
		}
		goto doNumber;
	    case 'k':
		number = eventPtr->xkey.keycode;
		goto doNumber;
	    case 'm':
		if (flags & CROSSING) {
		    number = eventPtr->xcrossing.mode;
		} else if (flags & FOCUS) {
		    number = eventPtr->xfocus.mode;
		}
		string = TkFindStateString(notifyMode, number);
		goto doString;
	    case 'o':
		if (flags & CREATE) {
		    number = eventPtr->xcreatewindow.override_redirect;
		} else if (flags & MAP) {
		    number = eventPtr->xmap.override_redirect;
		} else if (flags & REPARENT) {
		    number = eventPtr->xreparent.override_redirect;
		} else if (flags & CONFIG) {
		    number = eventPtr->xconfigure.override_redirect;
		}
		goto doNumber;
	    case 'p':
		string = TkFindStateString(circPlace, eventPtr->xcirculate.place);
		goto doString;
	    case 's':
		if (flags & (KEY_BUTTON_MOTION_VIRTUAL)) {
		    number = eventPtr->xkey.state;
		} else if (flags & CROSSING) {
		    number = eventPtr->xcrossing.state;
		} else if (flags & VISIBILITY) {
		    string = TkFindStateString(visNotify,
			    eventPtr->xvisibility.state);
		    goto doString;
		}
		goto doNumber;
	    case 't':
		if (flags & (KEY_BUTTON_MOTION_VIRTUAL)) {
		    number = (int) eventPtr->xkey.time;
		} else if (flags & CROSSING) {
		    number = (int) eventPtr->xcrossing.time;
		} else if (flags & PROP) {
		    number = (int) eventPtr->xproperty.time;
		}
		goto doNumber;
	    case 'v':
		number = eventPtr->xconfigurerequest.value_mask;
		goto doNumber;
	    case 'w':
		if (flags & EXPOSE) {
		    number = eventPtr->xexpose.width;
		} else if (flags & CONFIG) {
		    number = eventPtr->xconfigure.width;
		}
		goto doNumber;
	    case 'x':
		if (flags & (KEY_BUTTON_MOTION_VIRTUAL)) {
		    number = eventPtr->xkey.x;
		} else if (flags & CROSSING) {
		    number = eventPtr->xcrossing.x;
		} else if (flags & EXPOSE) {
		    number = eventPtr->xexpose.x;
		} else if (flags & (CREATE|CONFIG|GRAVITY)) {
		    number = eventPtr->xcreatewindow.x;
		} else if (flags & REPARENT) {
		    number = eventPtr->xreparent.x;
		}
		goto doNumber;
	    case 'y':
		if (flags & (KEY_BUTTON_MOTION_VIRTUAL)) {
		    number = eventPtr->xkey.y;
		} else if (flags & EXPOSE) {
		    number = eventPtr->xexpose.y;
		} else if (flags & (CREATE|CONFIG|GRAVITY)) {
		    number = eventPtr->xcreatewindow.y;
		} else if (flags & REPARENT) {
		    number = eventPtr->xreparent.y;
		} else if (flags & CROSSING) {
		    number = eventPtr->xcrossing.y;

		}
		goto doNumber;
	    case 'A':
		if (flags & KEY) {
		    int numChars;

		    /*
		     * If we're using input methods and this is a keypress
		     * event, invoke XmbTkFindStateString.  Otherwise just use
		     * the older XTkFindStateString.
		     */

#ifdef TK_USE_INPUT_METHODS
		    Status status;
		    if ((winPtr->inputContext != NULL)
			    && (eventPtr->type == KeyPress)) {
                        numChars = XmbLookupString(winPtr->inputContext,
                                &eventPtr->xkey, numStorage, NUM_SIZE,
                                (KeySym *) NULL, &status);
			if ((status != XLookupChars)
				&& (status != XLookupBoth)) {
			    numChars = 0;
			}
                    } else {
                        numChars = XLookupString(&eventPtr->xkey, numStorage,
                                NUM_SIZE, (KeySym *) NULL,
                                (XComposeStatus *) NULL);
		    }
#else /* TK_USE_INPUT_METHODS */
		    numChars = XLookupString(&eventPtr->xkey, numStorage,
			    NUM_SIZE, (KeySym *) NULL,
			    (XComposeStatus *) NULL);
#endif /* TK_USE_INPUT_METHODS */
		    numStorage[numChars] = '\0';
		    string = numStorage;
		}
		goto doString;
	    case 'B':
		number = eventPtr->xcreatewindow.border_width;
		goto doNumber;
	    case 'E':
		number = (int) eventPtr->xany.send_event;
		goto doNumber;
	    case 'K':
		if (flags & KEY) {
		    char *name;

		    name = TkKeysymToString(keySym);
		    if (name != NULL) {
			string = name;
		    }
		}
		goto doString;
	    case 'N':
		number = (int) keySym;
		goto doNumber;
	    case 'R':
		number = (int) eventPtr->xkey.root;
		goto doNumber;
	    case 'S':
		sprintf(numStorage, "0x%x", (int) eventPtr->xkey.subwindow);
		string = numStorage;
		goto doString;
	    case 'T':
		number = eventPtr->type;
		goto doNumber;
	    case 'W': {
		Tk_Window tkwin;

		tkwin = Tk_IdToWindow(eventPtr->xany.display,
			eventPtr->xany.window);
		if (tkwin != NULL) {
		    string = Tk_PathName(tkwin);
		} else {
		    string = "??";
		}
		goto doString;
	    }
	    case 'X': {
		Tk_Window tkwin;
		int x, y;
		int width, height;

		number = eventPtr->xkey.x_root;
		tkwin = Tk_IdToWindow(eventPtr->xany.display,
			eventPtr->xany.window);
		if (tkwin != NULL) {
		    Tk_GetVRootGeometry(tkwin, &x, &y, &width, &height);
		    number -= x;
		}
		goto doNumber;
	    }
	    case 'Y': {
		Tk_Window tkwin;
		int x, y;
		int width, height;

		number = eventPtr->xkey.y_root;
		tkwin = Tk_IdToWindow(eventPtr->xany.display,
			eventPtr->xany.window);
		if (tkwin != NULL) {
		    Tk_GetVRootGeometry(tkwin, &x, &y, &width, &height);
		    number -= y;
		}
		goto doNumber;
	    }
	    default:
		numStorage[0] = before[1];
		numStorage[1] = '\0';
		string = numStorage;
		goto doString;
	}

	doNumber:
	sprintf(numStorage, "%d", number);
	string = numStorage;

	doString:
	spaceNeeded = Tcl_ScanElement(string, &cvtFlags);
	length = Tcl_DStringLength(dsPtr);
	Tcl_DStringSetLength(dsPtr, length + spaceNeeded);
	spaceNeeded = Tcl_ConvertElement(string,
		Tcl_DStringValue(dsPtr) + length,
		cvtFlags | TCL_DONT_USE_BRACES);
	Tcl_DStringSetLength(dsPtr, length + spaceNeeded);
	before += 2;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * FreeScreenInfo --
 *
 *	This procedure is invoked when an interpreter is deleted in
 *	order to free the ScreenInfo structure associated with the
 *	"tkBind" AssocData.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Storage is freed.
 *
 *----------------------------------------------------------------------
 */

static void
FreeScreenInfo(clientData, interp)
    ClientData clientData;		/* Pointer to ScreenInfo structure. */
    Tcl_Interp *interp;			/* Interpreter that is being deleted. */
{
    ckfree((char *) clientData);
}

/*
 *----------------------------------------------------------------------
 *
 * ChangeScreen --
 *
 *	This procedure is invoked whenever the current screen changes
 *	in an application.  It invokes a Tcl procedure named
 *	"tkScreenChanged", passing it the screen name as argument.
 *	tkScreenChanged does things like making the tkPriv variable
 *	point to an array for the current display.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Depends on what tkScreenChanged does.  If an error occurs
 *	them tkError will be invoked.
 *
 *----------------------------------------------------------------------
 */

static void
ChangeScreen(interp, dispName, screenIndex)
    Tcl_Interp *interp;			/* Interpreter in which to invoke
					 * command. */
    char *dispName;			/* Name of new display. */
    int screenIndex;			/* Index of new screen. */
{
    Tcl_DString cmd;
    int code;
    char screen[30];

    Tcl_DStringInit(&cmd);
    Tcl_DStringAppend(&cmd, "tkScreenChanged ", 16);
    Tcl_DStringAppend(&cmd, dispName, -1);
    sprintf(screen, ".%d", screenIndex);
    Tcl_DStringAppend(&cmd, screen, -1);
    code = Tcl_GlobalEval(interp, Tcl_DStringValue(&cmd));
    if (code != TCL_OK) {
	Tcl_AddErrorInfo(interp,
		"\n    (changing screen in event binding)");
	Tcl_BackgroundError(interp);
    }
}


/*
 *----------------------------------------------------------------------
 *
 * Tk_EventCmd --
 *
 *	This procedure is invoked to process the "event" Tcl command.
 *	It is used to define and generate events.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

int
Tk_EventCmd(clientData, interp, argc, argv)
    ClientData clientData;	/* Main window associated with
				 * interpreter. */
    Tcl_Interp *interp;		/* Current interpreter. */
    int argc;			/* Number of arguments. */
    char **argv;		/* Argument strings. */
{
    int i;
    size_t length;
    char *option;
    TkWindow *winPtr;
    TkVirtualEventTable *vetPtr;

    if (argc < 2) {
	Tcl_AppendResult(interp, "wrong # args: should be \"",
		argv[0], " option ?arg1?\"", (char *) NULL);
	return TCL_ERROR;
    }

    option = argv[1];
    length = strlen(option);
    if (length == 0) {
	goto badopt;
    }

    winPtr = (TkWindow *) clientData;
    vetPtr = winPtr->mainPtr->vetPtr;

    if (strncmp(option, "add", length) == 0) {
	if (argc < 4) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		    " add virtual sequence ?sequence ...?\"", (char *) NULL);
	    return TCL_ERROR;
	}
	for (i = 3; i < argc; i++) {
	    if (CreateVirtualEvent(interp, vetPtr, argv[2], argv[i])
		    != TCL_OK) {
		return TCL_ERROR;
	    }
	}
    } else if (strncmp(option, "delete", length) == 0) {
	if (argc < 3) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		    " delete virtual ?sequence sequence ...?\"",
		    (char *) NULL);
	    return TCL_ERROR;
	}
	if (argc == 3) {
	    return DeleteVirtualEvent(interp, vetPtr, argv[2], NULL);
	}
	for (i = 3; i < argc; i++) {
	    if (DeleteVirtualEvent(interp, vetPtr, argv[2], argv[i])
		    != TCL_OK) {
		return TCL_ERROR;
	    }
	}
    } else if (strncmp(option, "generate", length) == 0) {
	if (argc < 4) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		    " generate window event ?options?\"", (char *) NULL);
	    return TCL_ERROR;
	}
	return HandleEventGenerate(interp, (Tk_Window) winPtr,
		argc - 2, argv + 2);
    } else if (strncmp(option, "info", length) == 0) {
	if (argc == 2) {
	    GetAllVirtualEvents(interp, vetPtr);
	    return TCL_OK;
	} else if (argc == 3) {	
	    return GetVirtualEvent(interp, vetPtr, argv[2]);
	} else {
	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		    " info ?virtual?\"", (char *) NULL);
	    return TCL_ERROR;
	}
    } else {
	badopt:
	Tcl_AppendResult(interp, "bad option \"", argv[1],
		"\": should be add, delete, generate, info", (char *) NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * CreateVirtualEventTable --
 *
 *	Set up a new domain in which virtual events may be defined.
 *
 * Results:
 *	The return value is a token for the new table, which must
 *	be passed to procedures like Tk_CreateVirtualEvent().
 *
 * Side effects:
 *	The caller must have already called Tk_CreateBindingTable() to
 *	properly set up memory used by the entire event-handling subsystem.
 *	Memory is allocated for the new table.
 *
 *--------------------------------------------------------------
 */
static TkVirtualEventTable *
CreateVirtualEventTable()
{
    TkVirtualEventTable *vetPtr;

    if (!initialized) {
	panic("CreateVirtualEvent: Tk_CreateBindingTable never called");
    }
    vetPtr = (TkVirtualEventTable *) ckalloc(sizeof(TkVirtualEventTable));
    Tcl_InitHashTable(&vetPtr->patternTable,
	    sizeof(PatternTableKey)/sizeof(int));
    Tcl_InitHashTable(&vetPtr->virtualTable, TCL_ONE_WORD_KEYS);

    return vetPtr;
}

/*
 *--------------------------------------------------------------
 *
 * DeleteVirtualEventTable --
 *
 *	Destroy a virtual event table and free up all its memory.
 *	The caller should not use virtualEventTable again after
 *	this procedure returns.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Memory is freed.
 *
 *--------------------------------------------------------------
 */

static void
DeleteVirtualEventTable(vetPtr)
    TkVirtualEventTable *vetPtr;/* The virtual event table to be destroyed. */
{
    Tcl_HashEntry *hPtr;
    Tcl_HashSearch search;
    PatSeq *psPtr, *nextPtr;

    hPtr = Tcl_FirstHashEntry(&vetPtr->patternTable, &search);
    for ( ; hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
	psPtr = (PatSeq *) Tcl_GetHashValue(hPtr);
	for ( ; psPtr != NULL; psPtr = nextPtr) {
	    nextPtr = psPtr->nextSeqPtr;
	    ckfree((char *) psPtr->voPtr);
	    ckfree((char *) psPtr);
	}
    }
    Tcl_DeleteHashTable(&vetPtr->patternTable);

    hPtr = Tcl_FirstHashEntry(&vetPtr->virtualTable, &search);
    for ( ; hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
        ckfree((char *) Tcl_GetHashValue(hPtr));
    }
    Tcl_DeleteHashTable(&vetPtr->virtualTable);

    ckfree((char *) vetPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * CreateVirtualEvent --
 *
 *	Add a new definition for a virtual event.  If the virtual event
 *	is already defined, the new definition augments those that
 *	already exist.
 *
 * Results:
 *	The return value is TCL_ERROR if an error occured while
 *	creating the virtual binding.  In this case, an error message
 *	will be left in interp->result.  If all went well then the return
 *	value is TCL_OK.
 *
 * Side effects:
 *	The virtual event may cause future calls to Tk_BindEvent to
 *	behave differently than they did previously.
 *
 *----------------------------------------------------------------------
 */

static int
CreateVirtualEvent(interp, vetPtr, virtString, eventString)
    Tcl_Interp *interp;		/* Used for error reporting. */
    TkVirtualEventTable *vetPtr;/* Table in which to augment virtual event. */
    char *virtString;		/* Name of new virtual event. */
    char *eventString;		/* String describing physical event that
				 * triggers virtual event. */
{
    PatSeq *psPtr;
    int dummy;
    Tcl_HashEntry *vhPtr;
    unsigned long eventMask;
    PhysicalsOwned *poPtr;
    VirtualOwners *voPtr;
    Tk_Uid virtUid;
    
    virtUid = GetVirtualEventUid(interp, virtString);
    if (virtUid == NULL) {
        return TCL_ERROR;
    }

    /*
     * Find/create physical event
     */

    psPtr = FindSequence(interp, &vetPtr->patternTable, NULL, eventString,
	    1, 0, &eventMask);
    if (psPtr == NULL) {
        return TCL_ERROR;
    }

    /*
     * Find/create virtual event.
     */

    vhPtr = Tcl_CreateHashEntry(&vetPtr->virtualTable, virtUid, &dummy);

    /*
     * Make virtual event own the physical event.
     */

    poPtr = (PhysicalsOwned *) Tcl_GetHashValue(vhPtr);
    if (poPtr == NULL) {
	poPtr = (PhysicalsOwned *) ckalloc(sizeof(PhysicalsOwned));
	poPtr->numOwned = 0;
    } else {
        /*
	 * See if this virtual event is already defined for this physical
	 * event and just return if it is.
	 */

	int i;
	for (i = 0; i < poPtr->numOwned; i++) {
	    if (poPtr->patSeqs[i] == psPtr) {
	        return TCL_OK;
	    }
	}
	poPtr = (PhysicalsOwned *) ckrealloc((char *) poPtr,
		sizeof(PhysicalsOwned) + poPtr->numOwned * sizeof(PatSeq *));
    }	
    Tcl_SetHashValue(vhPtr, (ClientData) poPtr);
    poPtr->patSeqs[poPtr->numOwned] = psPtr;
    poPtr->numOwned++;

    /*
     * Make physical event so it can trigger the virtual event.
     */

    voPtr = psPtr->voPtr;
    if (voPtr == NULL) {
        voPtr = (VirtualOwners *) ckalloc(sizeof(VirtualOwners));
	voPtr->numOwners = 0;
    } else {
        voPtr = (VirtualOwners *) ckrealloc((char *) voPtr,
		sizeof(VirtualOwners)
		+ voPtr->numOwners * sizeof(Tcl_HashEntry *));
    }
    psPtr->voPtr = voPtr;
    voPtr->owners[voPtr->numOwners] = vhPtr;
    voPtr->numOwners++;

    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * DeleteVirtualEvent --
 *
 *	Remove the definition of a given virtual event.  If the 
 *	event string is NULL, all definitions of the virtual event
 *	will be removed.  Otherwise, just the specified definition
 *	of the virtual event will be removed.
 *
 * Results:
 *	The result is a standard Tcl return value.  If an error
 *	occurs then interp->result will contain an error message.
 *	It is not an error to attempt to delete a virtual event that
 *	does not exist or a definition that does not exist.
 *
 * Side effects:
 *	The virtual event given by virtString may be removed from the
 *	virtual event table.  
 *
 *--------------------------------------------------------------
 */

static int
DeleteVirtualEvent(interp, vetPtr, virtString, eventString)
    Tcl_Interp *interp;		/* Used for error reporting. */
    TkVirtualEventTable *vetPtr;/* Table in which to delete event. */
    char *virtString;		/* String describing event sequence that
				 * triggers binding. */
    char *eventString;		/* The event sequence that should be deleted,
				 * or NULL to delete all event sequences for
				 * the entire virtual event. */
{
    int iPhys;
    Tk_Uid virtUid;
    Tcl_HashEntry *vhPtr;
    PhysicalsOwned *poPtr;
    PatSeq *eventPSPtr;

    virtUid = GetVirtualEventUid(interp, virtString);
    if (virtUid == NULL) {
        return TCL_ERROR;
    }
    
    vhPtr = Tcl_FindHashEntry(&vetPtr->virtualTable, virtUid);
    if (vhPtr == NULL) {
        return TCL_OK;
    }
    poPtr = (PhysicalsOwned *) Tcl_GetHashValue(vhPtr);

    eventPSPtr = NULL;
    if (eventString != NULL) {
	unsigned long eventMask;

	/*
	 * Delete only the specific physical event associated with the
	 * virtual event.  If the physical event doesn't already exist, or
	 * the virtual event doesn't own that physical event, return w/o
	 * doing anything.
	 */

	eventPSPtr = FindSequence(interp, &vetPtr->patternTable, NULL,
		eventString, 0, 0, &eventMask);
	if (eventPSPtr == NULL) {
	    return (interp->result[0] != '\0') ? TCL_ERROR : TCL_OK;
	}
    }

    for (iPhys = poPtr->numOwned; --iPhys >= 0; ) {
	PatSeq *psPtr = poPtr->patSeqs[iPhys];
	if ((eventPSPtr == NULL) || (psPtr == eventPSPtr)) {
	    int iVirt;
	    VirtualOwners *voPtr;
	    
	    /*
	     * Remove association between this physical event and the given
	     * virtual event that it triggers.
	     */

	    voPtr = psPtr->voPtr;
	    for (iVirt = 0; iVirt < voPtr->numOwners; iVirt++) {
		if (voPtr->owners[iVirt] == vhPtr) {
		    break;
		}
	    }
	    if (iVirt == voPtr->numOwners) {
		panic("DeleteVirtualEvent: couldn't find owner");
	    }
	    voPtr->numOwners--;
	    if (voPtr->numOwners == 0) {
		/*
		 * Removed last reference to this physical event, so
		 * remove it from physical->virtual map.
		 */
		PatSeq *prevPtr = (PatSeq *) Tcl_GetHashValue(psPtr->hPtr);
		if (prevPtr == psPtr) {
		    if (psPtr->nextSeqPtr == NULL) {
			Tcl_DeleteHashEntry(psPtr->hPtr);
		    } else {
			Tcl_SetHashValue(psPtr->hPtr,
				psPtr->nextSeqPtr);
		    }
		} else {
		    for ( ; ; prevPtr = prevPtr->nextSeqPtr) {
			if (prevPtr == NULL) {
			    panic("Tk_DeleteVirtualEvent couldn't find on hash chain");
			}
			if (prevPtr->nextSeqPtr == psPtr) {
			    prevPtr->nextSeqPtr = psPtr->nextSeqPtr;
			    break;
			}
		    }
		}
		ckfree((char *) psPtr->voPtr);
		ckfree((char *) psPtr);
	    } else {
		/*
		 * This physical event still triggers some other virtual
		 * event(s).  Consolidate the list of virtual owners for
		 * this physical event so it no longer triggers the
		 * given virtual event.
		 */
		voPtr->owners[iVirt] = voPtr->owners[voPtr->numOwners];
	    }

	    /*
	     * Now delete the virtual event's reference to the physical
	     * event.
	     */

	    poPtr->numOwned--;
	    if (eventPSPtr != NULL && poPtr->numOwned != 0) {
	        /*
		 * Just deleting this one physical event.  Consolidate list
		 * of owned physical events and return.
		 */

		poPtr->patSeqs[iPhys] = poPtr->patSeqs[poPtr->numOwned];
		return TCL_OK;
	    }
	}
    }

    if (poPtr->numOwned == 0) {
	/*
	 * All the physical events for this virtual event were deleted,
	 * either because there was only one associated physical event or
	 * because the caller was deleting the entire virtual event.  Now
	 * the virtual event itself should be deleted.
	 */

	ckfree((char *) poPtr);
	Tcl_DeleteHashEntry(vhPtr);
    }
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * GetVirtualEvent --
 *
 *	Return the list of physical events that can invoke the
 *	given virtual event.
 *
 * Results:
 *	The return value is TCL_OK and interp->result is filled with the
 *	string representation of the physical events associated with the
 *	virtual event; if there are no physical events for the given virtual
 *	event, interp->result is filled with and empty string.  If the
 *	virtual event string is improperly formed, then TCL_ERROR is
 *	returned and an error message is left in interp->result.
 *
 * Side effects:
 *	None.
 *
 *---------------------------------------------------------------------------
 */

static int
GetVirtualEvent(interp, vetPtr, virtString)
    Tcl_Interp *interp;		/* Interpreter for reporting. */
    TkVirtualEventTable *vetPtr;/* Table in which to look for event. */
    char *virtString;		/* String describing virtual event. */
{
    Tcl_HashEntry *vhPtr;
    Tcl_DString ds;
    int iPhys;
    PhysicalsOwned *poPtr;
    Tk_Uid virtUid;

    virtUid = GetVirtualEventUid(interp, virtString);
    if (virtUid == NULL) {
        return TCL_ERROR;
    }

    vhPtr = Tcl_FindHashEntry(&vetPtr->virtualTable, virtUid);
    if (vhPtr == NULL) {
        return TCL_OK;
    }

    Tcl_DStringInit(&ds);

    poPtr = (PhysicalsOwned *) Tcl_GetHashValue(vhPtr);
    for (iPhys = 0; iPhys < poPtr->numOwned; iPhys++) {
	Tcl_DStringSetLength(&ds, 0);
	GetPatternString(poPtr->patSeqs[iPhys], &ds);
	Tcl_AppendElement(interp, Tcl_DStringValue(&ds));
    }
    Tcl_DStringFree(&ds);

    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * GetAllVirtualEvents --
 *
 *	Return a list that contains the names of all the virtual
 *	event defined.
 *
 * Results:
 *	There is no return value.  Interp->result is modified to
 *	hold a Tcl list with one entry for each virtual event in 
 *	virtualTable.  
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static void
GetAllVirtualEvents(interp, vetPtr)
    Tcl_Interp *interp;		/* Interpreter returning result. */
    TkVirtualEventTable *vetPtr;/* Table containing events. */
{
    Tcl_HashEntry *hPtr;
    Tcl_HashSearch search;
    Tcl_DString ds;

    Tcl_DStringInit(&ds);

    hPtr = Tcl_FirstHashEntry(&vetPtr->virtualTable, &search);
    for ( ; hPtr != NULL; hPtr = Tcl_NextHashEntry(&search)) {
	Tcl_DStringSetLength(&ds, 0);	
	Tcl_DStringAppend(&ds, "<<", 2);
	Tcl_DStringAppend(&ds, Tcl_GetHashKey(hPtr->tablePtr, hPtr), -1);
	Tcl_DStringAppend(&ds, ">>", 2);
        Tcl_AppendElement(interp, Tcl_DStringValue(&ds));
    }

    Tcl_DStringFree(&ds);
}

/*
 *---------------------------------------------------------------------------
 *
 * HandleEventGenerate --
 *
 *	Helper function for the "event generate" command.  Generate and
 *	process an XEvent, constructed from information parsed from the
 *	event description string and its optional arguments.
 *
 *	argv[0] contains name of the target window.
 *	argv[1] contains pattern string for one event (e.g, <Control-v>).
 *	argv[2..argc-1] contains -field/option pairs for specifying
 *		        additional detail in the generated event.
 *
 *	Either virtual or physical events can be generated this way.
 *	The event description string must contain the specification
 *	for only one event.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	When constructing the event, 
 *	 event.xany.serial is filled with the current X serial number.
 *	 event.xany.window is filled with the target window.
 *	 event.xany.display is filled with the target window's display.
 *	Any other fields in eventPtr which are not specified by the pattern
 *	string or the optional arguments, are set to 0.
 *
 *	The event may be handled sychronously or asynchronously, depending
 *	on the value specified by the optional "-when" option.  The
 *	default setting is synchronous.
 *
 *---------------------------------------------------------------------------
 */
static int
HandleEventGenerate(interp, tkwin, argc, argv)
    Tcl_Interp *interp;	    /* Interp for error messages and name lookup. */
    Tk_Window tkwin;	    /* Main window of this application. */
    int argc;		    /* Number of arguments. */
    char **argv;	    /* Argument strings. */
{
    Pattern pat;
    char *p;
    unsigned long eventMask;
    int count, i, state, flags, synch;
    Tcl_QueuePosition pos;
    XEvent event;    

    tkwin = Tk_NameToWindow(interp, argv[0], tkwin);
    if (tkwin == NULL) {
	return TCL_ERROR;
    }

    p = argv[1];
    count = ParseEventDescription(interp, &p, &pat, &eventMask);
    if (count == 0) {
	return TCL_ERROR;
    }
    if (count != 1) {
	interp->result = "Double or Triple modifier not allowed";
	return TCL_ERROR;
    }
    if (*p != '\0') {
	interp->result = "only one event specification allowed";
	return TCL_ERROR;
    }
    if (argc & 1) {
        Tcl_AppendResult(interp, "value for \"", argv[argc - 1],
		"\" missing", (char *) NULL);
	return TCL_ERROR;
    }

    memset((VOID *) &event, 0, sizeof(event));
    event.xany.type = pat.eventType;
    event.xany.serial = NextRequest(Tk_Display(tkwin));
    event.xany.send_event = False;
    event.xany.window = Tk_WindowId(tkwin);
    event.xany.display = Tk_Display(tkwin);

    flags = flagArray[event.xany.type];
    if (flags & (KEY_BUTTON_MOTION_VIRTUAL)) {
	event.xkey.state = pat.needMods;
	if (flags & KEY) {
	    /*
	     * When mapping from a keysym to a keycode, need information about
	     * the modifier state that should be used so that when they call 
	     * XKeycodeToKeysym	taking into account the xkey.state, they will
	     * get back the original keysym.  
	     */

	    if (pat.detail.keySym == NoSymbol) {
	        event.xkey.keycode = 0;
	    } else {
		event.xkey.keycode = XKeysymToKeycode(event.xany.display,
			pat.detail.keySym);
	    }
	    if (event.xkey.keycode != 0) {
		for (state = 0; state < 4; state++) {
		    if (XKeycodeToKeysym(event.xany.display,
			    event.xkey.keycode, state) == pat.detail.keySym) {
			if (state & 1) {
			    event.xkey.state |= ShiftMask;
			}
			if (state & 2) {
			    TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr; 
			    event.xkey.state |= dispPtr->modeModMask;
			}
			break;
		    }
		}
	    }
	} else if (flags & BUTTON) {
	    event.xbutton.button = pat.detail.button;
	} else if (flags & VIRTUAL) {
	    ((XVirtualEvent *) &event)->name = pat.detail.name;
	}
    }
    if (flags & (CREATE|DESTROY|UNMAP|MAP|REPARENT|CONFIG|GRAVITY|CIRC)) {
	event.xcreatewindow.window = event.xany.window;
    }

    /*
     * Process the remaining arguments to fill in additional fields
     * of the event.
     */

    synch = 1;
    pos = TCL_QUEUE_TAIL;
    for (i = 2; i < argc; i += 2) {
	char *field, *value;
	Tk_Window tkwin2;
	int number;
	KeySym keysym;
	
	field = argv[i];
	value = argv[i+1];

	if (strcmp(field, "-when") == 0) {
	    if (strcmp(value, "now") == 0) {
		synch = 1;
	    } else if (strcmp(value, "head") == 0) {
		pos = TCL_QUEUE_HEAD;
		synch = 0;
	    } else if (strcmp(value, "mark") == 0) {
		pos = TCL_QUEUE_MARK;
		synch = 0;
	    } else if (strcmp(value, "tail") == 0) {
		pos = TCL_QUEUE_TAIL;
		synch = 0;
	    } else {
		Tcl_AppendResult(interp, "bad position \"", value,
			"\": should be now, head, mark, tail", (char *) NULL);
		return TCL_ERROR;
	    }
	} else if (strcmp(field, "-above") == 0) {
	    if (value[0] == '.') {
		tkwin2 = Tk_NameToWindow(interp, value, tkwin);
		if (tkwin2 == NULL) {
		    return TCL_ERROR;
		}
		number = Tk_WindowId(tkwin2);
	    } else if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & CONFIG) {
		event.xconfigure.above = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-borderwidth") == 0) {
	    if (Tk_GetPixels(interp, tkwin, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & (CREATE|CONFIG)) {
		event.xcreatewindow.border_width = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-button") == 0) {
	    if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & BUTTON) {
	        event.xbutton.button = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-count") == 0) {
	    if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & EXPOSE) {
		event.xexpose.count = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-detail") == 0) {
	    number = TkFindStateNum(interp, field, notifyDetail, value);
	    if (number < 0) {
		return TCL_ERROR;
	    }
	    if (flags & FOCUS) {
		event.xfocus.detail = number;
	    } else if (flags & CROSSING) {
		event.xcrossing.detail = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-focus") == 0) {
	    if (Tcl_GetBoolean(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & CROSSING) {
		event.xcrossing.focus = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-height") == 0) {
	    if (Tk_GetPixels(interp, tkwin, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & EXPOSE) {
		 event.xexpose.height = number;
	    } else if (flags & CONFIG) {
		event.xconfigure.height = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-keycode") == 0) {
	    if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & KEY) {
	        event.xkey.keycode = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-keysym") == 0) {
	    keysym = TkStringToKeysym(value);
	    if (keysym == NoSymbol) {
		Tcl_AppendResult(interp, "unknown keysym \"", value,
			"\"", (char *) NULL);
		return TCL_ERROR;
	    }
	    /*
	     * When mapping from a keysym to a keycode, need information about
	     * the modifier state that should be used so that when they call 
	     * XKeycodeToKeysym	taking into account the xkey.state, they will
	     * get back the original keysym.  
	     */

	    number = XKeysymToKeycode(event.xany.display, keysym);
	    if (number == 0) {
		Tcl_AppendResult(interp, "no keycode for keysym \"", value,
			"\"", (char *) NULL);
		return TCL_ERROR;
	    }
	    for (state = 0; state < 4; state++) {
		if (XKeycodeToKeysym(event.xany.display, (unsigned) number,
			state) == keysym) {
		    if (state & 1) {
			event.xkey.state |= ShiftMask;
		    }
		    if (state & 2) {
			TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr; 
			event.xkey.state |= dispPtr->modeModMask;
		    }
		    break;
		}
	    }	    
	    if (flags & KEY) {
		event.xkey.keycode = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-mode") == 0) {
	    number = TkFindStateNum(interp, field, notifyMode, value);
	    if (number < 0) {
		return TCL_ERROR;
	    }
	    if (flags & CROSSING) {
		event.xcrossing.mode = number;
	    } else if (flags & FOCUS) {
		event.xfocus.mode = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-override") == 0) {
	    if (Tcl_GetBoolean(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & CREATE) {
		event.xcreatewindow.override_redirect = number;
	    } else if (flags & MAP) {
		event.xmap.override_redirect = number;
	    } else if (flags & REPARENT) {
		event.xreparent.override_redirect = number;
	    } else if (flags & CONFIG) {
		event.xconfigure.override_redirect = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-place") == 0) {
	    number = TkFindStateNum(interp, field, circPlace, value);
	    if (number < 0) {
		return TCL_ERROR;
	    }
	    if (flags & CIRC) {
		event.xcirculate.place = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-root") == 0) {
	    if (value[0] == '.') {
		tkwin2 = Tk_NameToWindow(interp, value, tkwin);
		if (tkwin2 == NULL) {
		    return TCL_ERROR;
		}
		number = Tk_WindowId(tkwin2);
	    } else if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {
		event.xkey.root = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-rootx") == 0) {
	    if (Tk_GetPixels(interp, tkwin, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {
		event.xkey.x_root = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-rooty") == 0) {
	    if (Tk_GetPixels(interp, tkwin, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {
		event.xkey.y_root = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-sendevent") == 0) {
	    if (Tcl_GetBoolean(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    event.xany.send_event = number;
	} else if (strcmp(field, "-serial") == 0) {
	    if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    event.xany.serial = number;
	} else if (strcmp(field, "-state") == 0) {
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {
		if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		    return TCL_ERROR;
		}
		if (flags & (KEY_BUTTON_MOTION_VIRTUAL)) {
		    event.xkey.state = number;
		} else {
		    event.xcrossing.state = number;
		}
	    } else if (flags & VISIBILITY) {
		number = TkFindStateNum(interp, field, visNotify, value);
		if (number < 0) {
		    return TCL_ERROR;
		}
		event.xvisibility.state = number;
	    } else {
		goto badopt;
	    }	    
	} else if (strcmp(field, "-subwindow") == 0) {
	    if (value[0] == '.') {
		tkwin2 = Tk_NameToWindow(interp, value, tkwin);
		if (tkwin2 == NULL) {
		    return TCL_ERROR;
		}
		number = Tk_WindowId(tkwin2);
	    } else if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {
		event.xkey.subwindow = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-time") == 0) {
	    if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {
		event.xkey.time = (Time) number;
	    } else if (flags & PROP) {
		event.xproperty.time = (Time) number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-width") == 0) {
	    if (Tk_GetPixels(interp, tkwin, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & EXPOSE) {
		event.xexpose.width = number;
	    } else if (flags & (CREATE|CONFIG)) {
		event.xcreatewindow.width = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-window") == 0) {
	    if (value[0] == '.') {
		tkwin2 = Tk_NameToWindow(interp, value, tkwin);
		if (tkwin2 == NULL) {
		    return TCL_ERROR;
		}
		number = Tk_WindowId(tkwin2);
	    } else if (Tcl_GetInt(interp, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    if (flags & (CREATE|DESTROY|UNMAP|MAP|REPARENT|CONFIG
		    |GRAVITY|CIRC)) {
		event.xcreatewindow.window = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-x") == 0) {
	    int rootX, rootY;
	    if (Tk_GetPixels(interp, tkwin, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    Tk_GetRootCoords(tkwin, &rootX, &rootY);
	    rootX += number;
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {	
		event.xkey.x = number;
		event.xkey.x_root = rootX;
	    } else if (flags & EXPOSE) {
		event.xexpose.x = number;
	    } else if (flags & (CREATE|CONFIG|GRAVITY)) { 
		event.xcreatewindow.x = number;
	    } else if (flags & REPARENT) {		
		event.xreparent.x = number;
	    } else {
		goto badopt;
	    }
	} else if (strcmp(field, "-y") == 0) {
	    int rootX, rootY;
	    if (Tk_GetPixels(interp, tkwin, value, &number) != TCL_OK) {
		return TCL_ERROR;
	    }
	    Tk_GetRootCoords(tkwin, &rootX, &rootY);
	    rootY += number;
	    if (flags & (KEY_BUTTON_MOTION_VIRTUAL|CROSSING)) {
		event.xkey.y = number;
		event.xkey.y_root = rootY;
	    } else if (flags & EXPOSE) {
		event.xexpose.y = number;
	    } else if (flags & (CREATE|CONFIG|GRAVITY)) {
		event.xcreatewindow.y = number;
	    } else if (flags & REPARENT) {
		event.xreparent.y = number;
	    } else {
		goto badopt;
	    }
	} else {
	    badopt:
	    Tcl_AppendResult(interp, "bad option to ", argv[1],
		    " event: \"", field, "\"", (char *) NULL);
	    return TCL_ERROR;
	}
    }

    if (synch != 0) {
	Tk_HandleEvent(&event);
    } else {
	Tk_QueueWindowEvent(&event, pos);
    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------------
 *
 * GetVirtualEventUid --
 *
 *	Determine if the given string is in the proper format for a
 *	virtual event.
 *
 * Results:
 *	The return value is NULL if the virtual event string was
 *	not in the proper format.  In this case, an error message
 *	will be left in interp->result.  Otherwise the return
 *	value is a Tk_Uid that represents the virtual event.
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------------
 */
static Tk_Uid
GetVirtualEventUid(interp, virtString)
    Tcl_Interp *interp;
    char *virtString;
{
    Tk_Uid uid;
    int length;

    length = strlen(virtString);

    if (length < 5 || virtString[0] != '<' || virtString[1] != '<' ||
	    virtString[length - 2] != '>' || virtString[length - 1] != '>') {
        Tcl_AppendResult(interp, "virtual event \"", virtString,
		"\" is badly formed", (char *) NULL);
        return NULL;
    }
    virtString[length - 2] = '\0';
    uid = Tk_GetUid(virtString + 2);
    virtString[length - 2] = '>';

    return uid;
}


/*
 *----------------------------------------------------------------------
 *
 * FindSequence --
 *
 *	Find the entry in the pattern table that corresponds to a
 *	particular pattern string, and return a pointer to that
 *	entry.
 *
 * Results:
 *	The return value is normally a pointer to the PatSeq
 *	in patternTable that corresponds to eventString.  If an error
 *	was found while parsing eventString, or if "create" is 0 and
 *	no pattern sequence previously existed, then NULL is returned
 *	and interp->result contains a message describing the problem.
 *	If no pattern sequence previously existed for eventString, then
 *	a new one is created with a NULL command field.  In a successful
 *	return, *maskPtr is filled in with a mask of the event types
 *	on which the pattern sequence depends.
 *
 * Side effects:
 *	A new pattern sequence may be allocated.
 *
 *----------------------------------------------------------------------
 */

static PatSeq *
FindSequence(interp, patternTablePtr, object, eventString, create,
	allowVirtual, maskPtr)
    Tcl_Interp *interp;		/* Interpreter to use for error
				 * reporting. */
    Tcl_HashTable *patternTablePtr; /* Table to use for lookup. */
    ClientData object;		/* For binding table, token for object with
				 * which binding is associated.
				 * For virtual event table, NULL. */
    char *eventString;		/* String description of pattern to
				 * match on.  See user documentation
				 * for details. */
    int create;			/* 0 means don't create the entry if
				 * it doesn't already exist.   Non-zero
				 * means create. */
    int allowVirtual;		/* 0 means that virtual events are not
				 * allowed in the sequence.  Non-zero
				 * otherwise. */
    unsigned long *maskPtr;	/* *maskPtr is filled in with the event
				 * types on which this pattern sequence
				 * depends. */
{

    Pattern pats[EVENT_BUFFER_SIZE];
    int numPats, virtualFound;
    char *p;
    Pattern *patPtr;
    PatSeq *psPtr;
    Tcl_HashEntry *hPtr;
    int flags, count, new;
    size_t sequenceSize;
    unsigned long eventMask;
    PatternTableKey key;

    /*
     *-------------------------------------------------------------
     * Step 1: parse the pattern string to produce an array
     * of Patterns.  The array is generated backwards, so
     * that the lowest-indexed pattern corresponds to the last
     * event that must occur.
     *-------------------------------------------------------------
     */

    p = eventString;
    flags = 0;
    eventMask = 0;
    virtualFound = 0;

    patPtr = &pats[EVENT_BUFFER_SIZE-1];
    for (numPats = 0; numPats < EVENT_BUFFER_SIZE; numPats++, patPtr--) {
	while (isspace(UCHAR(*p))) {
	    p++;
	}
	if (*p == '\0') {
	    break;
	}

	count = ParseEventDescription(interp, &p, patPtr, &eventMask);
	if (count == 0) {
	    return NULL;
	}

	if (eventMask & VirtualEventMask) {
	    if (allowVirtual == 0) {
		interp->result =
			"virtual event not allowed in definition of another virtual event";
		return NULL;
	    }
	    virtualFound = 1;
	}

	/*
	 * Replicate events for DOUBLE and TRIPLE.
	 */

	if ((count > 1) && (numPats < EVENT_BUFFER_SIZE-1)) {
	    flags |= PAT_NEARBY;
	    patPtr[-1] = patPtr[0];
	    patPtr--;
	    numPats++;
	    if ((count == 3) && (numPats < EVENT_BUFFER_SIZE-1)) {
		patPtr[-1] = patPtr[0];
		patPtr--;
		numPats++;
	    }
	}
    }

    /*
     *-------------------------------------------------------------
     * Step 2: find the sequence in the binding table if it exists,
     * and add a new sequence to the table if it doesn't.
     *-------------------------------------------------------------
     */

    if (numPats == 0) {
	interp->result = "no events specified in binding";
	return NULL;
    }
    if ((numPats > 1) && (virtualFound != 0)) {
        interp->result = "virtual events may not be composed";
	return NULL;
    }
    
    patPtr = &pats[EVENT_BUFFER_SIZE-numPats];
    memset(&key, 0, sizeof(key));
    key.object = object;
    key.type = patPtr->eventType;
    key.detail = patPtr->detail;
    hPtr = Tcl_CreateHashEntry(patternTablePtr, (char *) &key, &new);
    sequenceSize = numPats*sizeof(Pattern);
    if (!new) {
	for (psPtr = (PatSeq *) Tcl_GetHashValue(hPtr); psPtr != NULL;
		psPtr = psPtr->nextSeqPtr) {
	    if ((numPats == psPtr->numPats)
		    && ((flags & PAT_NEARBY) == (psPtr->flags & PAT_NEARBY))
		    && (memcmp((char *) patPtr, (char *) psPtr->pats,
		    sequenceSize) == 0)) {
		goto done;
	    }
	}
    }
    if (!create) {
	if (new) {
	    Tcl_DeleteHashEntry(hPtr);
	}
/*	Tcl_AppendResult(interp, "no binding exists for \"",
		eventString, "\"", (char *) NULL);*/
	return NULL;
    }
    psPtr = (PatSeq *) ckalloc((unsigned) (sizeof(PatSeq)
	    + (numPats-1)*sizeof(Pattern)));
    psPtr->numPats = numPats;
    psPtr->command = NULL;
    psPtr->flags = flags;
    psPtr->nextSeqPtr = (PatSeq *) Tcl_GetHashValue(hPtr);
    psPtr->hPtr = hPtr;
    psPtr->voPtr = NULL;
    psPtr->nextObjPtr = NULL;
    Tcl_SetHashValue(hPtr, psPtr);

    memcpy((VOID *) psPtr->pats, (VOID *) patPtr, sequenceSize);

    done:
    *maskPtr = eventMask;
    return psPtr;
}

/*
 *---------------------------------------------------------------------------
 *
 * ParseEventDescription --
 *
 *	Fill Pattern buffer with information about event from
 *	event string.
 *
 * Results:
 *	Leaves error message in interp and returns 0 if there was an
 *	error due to a badly formed event string.  Returns 1 if proper
 *	event was specified, 2 if Double modifier was used in event
 *	string, or 3 if Triple was used.
 *
 * Side effects:
 *	On exit, eventStringPtr points to rest of event string (after the
 *	closing '>', so that this procedure can be called repeatedly to
 *	parse all the events in the entire sequence.
 *
 *---------------------------------------------------------------------------
 */

static int
ParseEventDescription(interp, eventStringPtr, patPtr,
	eventMaskPtr)
    Tcl_Interp *interp;		/* For error messages. */
    char **eventStringPtr;	/* On input, holds a pointer to start of
				 * event string.  On exit, gets pointer to
				 * rest of string after parsed event. */
    Pattern *patPtr;		/* Filled with the pattern parsed from the
				 * event string. */
    unsigned long *eventMaskPtr;/* Filled with event mask of matched event. */
				 
{
    char *p;
    unsigned long eventMask;
    int count, eventFlags;
#define FIELD_SIZE 48
    char field[FIELD_SIZE];
    Tcl_HashEntry *hPtr;

    p = *eventStringPtr;

    patPtr->eventType = -1;
    patPtr->needMods = 0;
    patPtr->detail.clientData = 0;

    eventMask = 0;
    count = 1;
    
    /*
     * Handle simple ASCII characters.
     */

    if (*p != '<') {
	char string[2];

	patPtr->eventType = KeyPress;
	eventMask = KeyPressMask;
	string[0] = *p;
	string[1] = 0;
	patPtr->detail.keySym = TkStringToKeysym(string);
	if (patPtr->detail.keySym == NoSymbol) {
	    if (isprint(UCHAR(*p))) {
		patPtr->detail.keySym = *p;
	    } else {
		sprintf(interp->result,
			"bad ASCII character 0x%x", (unsigned char) *p);
		return 0;
	    }
	}
	p++;
	goto end;
    }

    /*
     * A fancier event description.  This can be either a virtual event
     * or a physical event.
     *
     * A virtual event description consists of:
     *
     * 1. double open angle brackets.
     * 2. virtual event name.
     * 3. double close angle brackets.
     *
     * A physical event description consists of:
     *
     * 1. open angle bracket.
     * 2. any number of modifiers, each followed by spaces
     *    or dashes.
     * 3. an optional event name.
     * 4. an option button or keysym name.  Either this or
     *    item 3 *must* be present;  if both are present
     *    then they are separated by spaces or dashes.
     * 5. a close angle bracket.
     */

    p++;
    if (*p == '<') {
	/*
	 * This is a virtual event: soak up all the characters up to
	 * the next '>'.
	 */

	char *field = p + 1;	    
	p = strchr(field, '>');
	if (p == field) {
	    interp->result = "virtual event \"<<>>\" is badly formed";
	    return 0;
	}	    
	if ((p == NULL) || (p[1] != '>')) {
	    interp->result = "missing \">\" in virtual binding";
	    return 0;
	}
	*p = '\0';
	patPtr->eventType = VirtualEvent;
	eventMask = VirtualEventMask;
	patPtr->detail.name = Tk_GetUid(field);
	*p = '>';

	p += 2;
	goto end;
    }

    while (1) {
	ModInfo *modPtr;
	p = GetField(p, field, FIELD_SIZE);
	hPtr = Tcl_FindHashEntry(&modTable, field);
	if (hPtr == NULL) {
	    break;
	}
	modPtr = (ModInfo *) Tcl_GetHashValue(hPtr);
	patPtr->needMods |= modPtr->mask;
	if (modPtr->flags & (DOUBLE|TRIPLE)) {
	    if (modPtr->flags & DOUBLE) {
		count = 2;
	    } else {
		count = 3;
	    }
	}
	while ((*p == '-') || isspace(UCHAR(*p))) {
	    p++;
	}
    }

    eventFlags = 0;
    hPtr = Tcl_FindHashEntry(&eventTable, field);
    if (hPtr != NULL) {
	EventInfo *eiPtr;
	eiPtr = (EventInfo *) Tcl_GetHashValue(hPtr);

	patPtr->eventType = eiPtr->type;
	eventFlags = flagArray[eiPtr->type];
	eventMask = eiPtr->eventMask;
	while ((*p == '-') || isspace(UCHAR(*p))) {
	    p++;
	}
	p = GetField(p, field, FIELD_SIZE);
    }
    if (*field != '\0') {
	if ((*field >= '1') && (*field <= '5') && (field[1] == '\0')) {
	    if (eventFlags == 0) {
		patPtr->eventType = ButtonPress;
		eventMask = ButtonPressMask;
	    } else if (eventFlags & KEY) {
		goto getKeysym;
	    } else if ((eventFlags & BUTTON) == 0) {
		Tcl_AppendResult(interp, "specified button \"", field,
			"\" for non-button event", (char *) NULL);
		return 0;
	    }
	    patPtr->detail.button = (*field - '0');
	} else {
	    getKeysym:
	    patPtr->detail.keySym = TkStringToKeysym(field);
	    if (patPtr->detail.keySym == NoSymbol) {
		Tcl_AppendResult(interp, "bad event type or keysym \"",
			field, "\"", (char *) NULL);
		return 0;
	    }
	    if (eventFlags == 0) {
		patPtr->eventType = KeyPress;
		eventMask = KeyPressMask;
	    } else if ((eventFlags & KEY) == 0) {
		Tcl_AppendResult(interp, "specified keysym \"", field,
			"\" for non-key event", (char *) NULL);
		return 0;
	    }
	}
    } else if (eventFlags == 0) {
	interp->result = "no event type or button # or keysym";
	return 0;
    }

    while ((*p == '-') || isspace(UCHAR(*p))) {
	p++;
    }
    if (*p != '>') {
	while (*p != '\0') {
	    p++;
	    if (*p == '>') {
		interp->result = "extra characters after detail in binding";
		return 0;
	    }
	}
	interp->result = "missing \">\" in binding";
	return 0;
    }
    p++;

end:
    *eventStringPtr = p;
    *eventMaskPtr |= eventMask;
    return count;
}

/*
 *----------------------------------------------------------------------
 *
 * GetField --
 *
 *	Used to parse pattern descriptions.  Copies up to
 *	size characters from p to copy, stopping at end of
 *	string, space, "-", ">", or whenever size is
 *	exceeded.
 *
 * Results:
 *	The return value is a pointer to the character just
 *	after the last one copied (usually "-" or space or
 *	">", but could be anything if size was exceeded).
 *	Also places NULL-terminated string (up to size
 *	character, including NULL), at copy.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static char *
GetField(p, copy, size)
    char *p;		/* Pointer to part of pattern. */
    char *copy;	/* Place to copy field. */
    int size;			/* Maximum number of characters to
				 * copy. */
{
    while ((*p != '\0') && !isspace(UCHAR(*p)) && (*p != '>')
	    && (*p != '-') && (size > 1)) {
	*copy = *p;
	p++;
	copy++;
	size--;
    }
    *copy = '\0';
    return p;
}

/*
 *---------------------------------------------------------------------------
 *
 * GetPatternString --
 *
 *	Produce a string version of the given event, for displaying to
 *	the user.  
 *
 * Results:
 *	The string is left in dsPtr.
 *
 * Side effects:
 *	It is the caller's responsibility to initialize the DString before
 *	and to free it after calling this procedure.
 *
 *---------------------------------------------------------------------------
 */
static void
GetPatternString(psPtr, dsPtr)
    PatSeq *psPtr;
    Tcl_DString *dsPtr;
{
    Pattern *patPtr;
    char c, buffer[10];
    int patsLeft, needMods;
    ModInfo *modPtr;
    EventInfo *eiPtr;

    /*
     * The order of the patterns in the sequence is backwards from the order
     * in which they must be output.
     */

    for (patsLeft = psPtr->numPats, patPtr = &psPtr->pats[psPtr->numPats - 1];
	    patsLeft > 0; patsLeft--, patPtr--) {

	/*
	 * Check for simple case of an ASCII character.
	 */

	if ((patPtr->eventType == KeyPress)
		&& ((psPtr->flags & PAT_NEARBY) == 0) 
		&& (patPtr->needMods == 0)
		&& (patPtr->detail.keySym < 128)
		&& isprint(UCHAR(patPtr->detail.keySym))
		&& (patPtr->detail.keySym != '<')
		&& (patPtr->detail.keySym != ' ')) {

	    c = (char) patPtr->detail.keySym;
	    Tcl_DStringAppend(dsPtr, &c, 1);
	    continue;
	}

	/*
	 * Check for virtual event.
	 */

	if (patPtr->eventType == VirtualEvent) {
	    Tcl_DStringAppend(dsPtr, "<<", 2);
	    Tcl_DStringAppend(dsPtr, patPtr->detail.name, -1);
	    Tcl_DStringAppend(dsPtr, ">>", 2);
	    continue;
	}

	/*
	 * It's a more general event specification.  First check
	 * for "Double" or "Triple", then modifiers, then event type,
	 * then keysym or button detail.
	 */

	Tcl_DStringAppend(dsPtr, "<", 1);
	if ((psPtr->flags & PAT_NEARBY) && (patsLeft > 1)
		&& (memcmp((char *) patPtr, (char *) (patPtr-1),
			sizeof(Pattern)) == 0)) {
	    patsLeft--;
	    patPtr--;
	    if ((patsLeft > 1) && (memcmp((char *) patPtr,
		    (char *) (patPtr-1), sizeof(Pattern)) == 0)) {
		patsLeft--;
		patPtr--;
		Tcl_DStringAppend(dsPtr, "Triple-", 7);
	    } else {
		Tcl_DStringAppend(dsPtr, "Double-", 7);
	    }
	}
	for (needMods = patPtr->needMods, modPtr = modArray;
		needMods != 0; modPtr++) {
	    if (modPtr->mask & needMods) {
		needMods &= ~modPtr->mask;
		Tcl_DStringAppend(dsPtr, modPtr->name, -1);
		Tcl_DStringAppend(dsPtr, "-", 1);
	    }
	}
	for (eiPtr = eventArray; eiPtr->name != NULL; eiPtr++) {
	    if (eiPtr->type == patPtr->eventType) {
		Tcl_DStringAppend(dsPtr, eiPtr->name, -1);
		if (patPtr->detail.clientData != 0) {
		    Tcl_DStringAppend(dsPtr, "-", 1);
		}
		break;
	    }
	}

	if (patPtr->detail.clientData != 0) {
	    if ((patPtr->eventType == KeyPress)
		    || (patPtr->eventType == KeyRelease)) {
		char *string;

		string = TkKeysymToString(patPtr->detail.keySym);
		if (string != NULL) {
		    Tcl_DStringAppend(dsPtr, string, -1);
		}
	    } else {
		sprintf(buffer, "%d", patPtr->detail.button);
		Tcl_DStringAppend(dsPtr, buffer, -1);
	    }
	}
	Tcl_DStringAppend(dsPtr, ">", 1);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * GetKeySym --
 *
 *	Given an X KeyPress or KeyRelease event, map the
 *	keycode in the event into a KeySym.
 *
 * Results:
 *	The return value is the KeySym corresponding to
 *	eventPtr, or NoSymbol if no matching Keysym could be
 *	found.
 *
 * Side effects:
 *	In the first call for a given display, keycode-to-
 *	KeySym maps get loaded.
 *
 *----------------------------------------------------------------------
 */

static KeySym
GetKeySym(dispPtr, eventPtr)
    TkDisplay *dispPtr;	/* Display in which to
					 * map keycode. */
    XEvent *eventPtr;		/* Description of X event. */
{
    KeySym sym;
    int index;

    /*
     * Refresh the mapping information if it's stale
     */

    if (dispPtr->bindInfoStale) {
	InitKeymapInfo(dispPtr);
    }

    /*
     * Figure out which of the four slots in the keymap vector to
     * use for this key.  Refer to Xlib documentation for more info
     * on how this computation works.
     */

    index = 0;
    if (eventPtr->xkey.state & dispPtr->modeModMask) {
	index = 2;
    }
    if ((eventPtr->xkey.state & ShiftMask)
	    || ((dispPtr->lockUsage != LU_IGNORE)
	    && (eventPtr->xkey.state & LockMask))) {
	index += 1;
    }
    sym = XKeycodeToKeysym(dispPtr->display, eventPtr->xkey.keycode, index);

    /*
     * Special handling:  if the key was shifted because of Lock, but
     * lock is only caps lock, not shift lock, and the shifted keysym
     * isn't upper-case alphabetic, then switch back to the unshifted
     * keysym.
     */

    if ((index & 1) && !(eventPtr->xkey.state & ShiftMask)
	    && (dispPtr->lockUsage == LU_CAPS)) {
	if (!(((sym >= XK_A) && (sym <= XK_Z))
		|| ((sym >= XK_Agrave) && (sym <= XK_Odiaeresis))
		|| ((sym >= XK_Ooblique) && (sym <= XK_Thorn)))) {
	    index &= ~1;
	    sym = XKeycodeToKeysym(dispPtr->display, eventPtr->xkey.keycode,
		    index);
	}
    }

    /*
     * Another bit of special handling:  if this is a shifted key and there
     * is no keysym defined, then use the keysym for the unshifted key.
     */

    if ((index & 1) && (sym == NoSymbol)) {
	sym = XKeycodeToKeysym(dispPtr->display, eventPtr->xkey.keycode,
		    index & ~1);
    }
    return sym;
}

/*
 *--------------------------------------------------------------
 *
 * InitKeymapInfo --
 *
 *	This procedure is invoked to scan keymap information
 *	to recompute stuff that's important for binding, such
 *	as the modifier key (if any) that corresponds to "mode
 *	switch".
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Keymap-related information in dispPtr is updated.
 *
 *--------------------------------------------------------------
 */

static void
InitKeymapInfo(dispPtr)
    TkDisplay *dispPtr;		/* Display for which to recompute keymap
				 * information. */
{
    XModifierKeymap *modMapPtr;
    KeyCode *codePtr;
    KeySym keysym;
    int count, i, j, max, arraySize;
#define KEYCODE_ARRAY_SIZE 20

    dispPtr->bindInfoStale = 0;
    modMapPtr = XGetModifierMapping(dispPtr->display);

    /*
     * Check the keycodes associated with the Lock modifier.  If
     * any of them is associated with the XK_Shift_Lock modifier,
     * then Lock has to be interpreted as Shift Lock, not Caps Lock.
     */

    dispPtr->lockUsage = LU_IGNORE;
    codePtr = modMapPtr->modifiermap + modMapPtr->max_keypermod*LockMapIndex;
    for (count = modMapPtr->max_keypermod; count > 0; count--, codePtr++) {
	if (*codePtr == 0) {
	    continue;
	}
	keysym = XKeycodeToKeysym(dispPtr->display, *codePtr, 0);
	if (keysym == XK_Shift_Lock) {
	    dispPtr->lockUsage = LU_SHIFT;
	    break;
	}
	if (keysym == XK_Caps_Lock) {
	    dispPtr->lockUsage = LU_CAPS;
	    break;
	}
    }

    /*
     * Look through the keycodes associated with modifiers to see if
     * the the "mode switch", "meta", or "alt" keysyms are associated
     * with any modifiers.  If so, remember their modifier mask bits.
     */

    dispPtr->modeModMask = 0;
    dispPtr->metaModMask = 0;
    dispPtr->altModMask = 0;
    codePtr = modMapPtr->modifiermap;
    max = 8*modMapPtr->max_keypermod;
    for (i = 0; i < max; i++, codePtr++) {
	if (*codePtr == 0) {
	    continue;
	}
	keysym = XKeycodeToKeysym(dispPtr->display, *codePtr, 0);
	if (keysym == XK_Mode_switch) {
	    dispPtr->modeModMask |= ShiftMask << (i/modMapPtr->max_keypermod);
	}
	if ((keysym == XK_Meta_L) || (keysym == XK_Meta_R)) {
	    dispPtr->metaModMask |= ShiftMask << (i/modMapPtr->max_keypermod);
	}
	if ((keysym == XK_Alt_L) || (keysym == XK_Alt_R)) {
	    dispPtr->altModMask |= ShiftMask << (i/modMapPtr->max_keypermod);
	}
    }

    /*
     * Create an array of the keycodes for all modifier keys.
     */

    if (dispPtr->modKeyCodes != NULL) {
	ckfree((char *) dispPtr->modKeyCodes);
    }
    dispPtr->numModKeyCodes = 0;
    arraySize = KEYCODE_ARRAY_SIZE;
    dispPtr->modKeyCodes = (KeyCode *) ckalloc((unsigned)
	    (KEYCODE_ARRAY_SIZE * sizeof(KeyCode)));
    for (i = 0, codePtr = modMapPtr->modifiermap; i < max; i++, codePtr++) {
	if (*codePtr == 0) {
	    continue;
	}

	/*
	 * Make sure that the keycode isn't already in the array.
	 */

	for (j = 0; j < dispPtr->numModKeyCodes; j++) {
	    if (dispPtr->modKeyCodes[j] == *codePtr) {
		goto nextModCode;
	    }
	}
	if (dispPtr->numModKeyCodes >= arraySize) {
	    KeyCode *new;

	    /*
	     * Ran out of space in the array;  grow it.
	     */

	    arraySize *= 2;
	    new = (KeyCode *) ckalloc((unsigned)
		    (arraySize * sizeof(KeyCode)));
	    memcpy((VOID *) new, (VOID *) dispPtr->modKeyCodes,
		    (dispPtr->numModKeyCodes * sizeof(KeyCode)));
	    ckfree((char *) dispPtr->modKeyCodes);
	    dispPtr->modKeyCodes = new;
	}
	dispPtr->modKeyCodes[dispPtr->numModKeyCodes] = *codePtr;
	dispPtr->numModKeyCodes++;
	nextModCode: continue;
    }
    XFreeModifiermap(modMapPtr);
}


/*
 *----------------------------------------------------------------------
 *
 * TkStringToKeysym --
 *
 *	This procedure finds the keysym associated with a given keysym
 *	name.
 *
 * Results:
 *	The return value is the keysym that corresponds to name, or
 *	NoSymbol if there is no such keysym.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

KeySym
TkStringToKeysym(name)
    char *name;			/* Name of a keysym. */
{
#ifdef REDO_KEYSYM_LOOKUP
    Tcl_HashEntry *hPtr;
    KeySym keysym;

    hPtr = Tcl_FindHashEntry(&keySymTable, name);
    if (hPtr != NULL) {
	return (KeySym) Tcl_GetHashValue(hPtr);
    }
    if (strlen(name) == 1) {
	keysym = (KeySym) (unsigned char) name[0];
	if (TkKeysymToString(keysym) != NULL) {
	    return keysym;
	}
    }
#endif /* REDO_KEYSYM_LOOKUP */
    return XStringToKeysym(name);
}

/*
 *----------------------------------------------------------------------
 *
 * TkKeysymToString --
 *
 *	This procedure finds the keysym name associated with a given
 *	keysym.
 *
 * Results:
 *	The return value is a pointer to a static string containing
 *	the name of the given keysym, or NULL if there is no known name.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

char *
TkKeysymToString(keysym)
    KeySym keysym;
{
#ifdef REDO_KEYSYM_LOOKUP
    Tcl_HashEntry *hPtr;

    hPtr = Tcl_FindHashEntry(&nameTable, (char *)keysym);
    if (hPtr != NULL) {
	return (char *) Tcl_GetHashValue(hPtr);
    }
#endif /* REDO_KEYSYM_LOOKUP */
    return XKeysymToString(keysym);
}

/*
 *----------------------------------------------------------------------
 *
 * TkCopyAndGlobalEval --
 *
 *	This procedure makes a copy of a script then calls Tcl_GlobalEval
 *	to evaluate it.  It's used in situations where the execution of
 *	a command may cause the original command string to be reallocated.
 *
 * Results:
 *	Returns the result of evaluating script, including both a standard
 *	Tcl completion code and a string in interp->result.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkCopyAndGlobalEval(interp, script)
    Tcl_Interp *interp;			/* Interpreter in which to evaluate
					 * script. */
    char *script;			/* Script to evaluate. */
{
    Tcl_DString buffer;
    int code;

    Tcl_DStringInit(&buffer);
    Tcl_DStringAppend(&buffer, script, -1);
    code = Tcl_GlobalEval(interp, Tcl_DStringValue(&buffer));
    Tcl_DStringFree(&buffer);
    return code;
}


