typedef struct TkText TkText;typedef struct TkTitem TkTitem;typedef struct TkTline TkTline;typedef struct TkTindex TkTindex;typedef struct TkTmarkinfo TkTmarkinfo;typedef struct TkTtaginfo TkTtaginfo;typedef struct TkTwind TkTwind; enum{	/* text item types */	TkTascii,	/* contiguous string of ascii chars, all with same tags */	TkTrune,	/* printable utf (one printing position) */	TkTtab,	TkTnewline,	/* line field contains pointer to containing line */	TkTcontline,	/* end of non-newline line; line field as with TkTnewline */	TkTwin,	TkTmark, 	TkTbyitem = 0,	/* adjustment units */	TkTbyitemback,	TkTbytline,	TkTbytlineback,	TkTbychar,	TkTbycharback,	TkTbycharstart,	TkTbyline,	TkTbylineback,	TkTbylinestart,	TkTbylineend,	TkTbywordstart,	TkTbywordend,	TkTbywrapstart,	TkTbywrapend, 	TkTselid	= 0,		/* id of sel tag */	TkTmaxtag	= 32,	Textwidth	= 40,		/* default width, in chars */	Textheight	= 10,		/* default height, in chars */ 	TkTfirst	= (1<<0),	/* first line in buffer, or after a TkTlast */	TkTlast		= (1<<1),	/* TkTnewline at end of line */	TkTdrawn	= (1<<2),	/* screen cache copy is ok */	TkTdlocked	= (1<<3),	/* display already locked */	TkTjustfoc	= (1<<4),	/* got focus on last B1 press */	TkTnodrag		= (1<<5),	/* ignore B1 drag until B1 up */	TkTunset 	= (1<<31),	/* marks int tag options "unspecified" */ 	TkTborderwidth	= 0,	TkTjustify,	TkTlmargin1,	TkTlmargin2,	TkTlmargin3,	TkTrmargin,	TkTspacing1,	TkTspacing2,	TkTspacing3,	TkToffset,	TkTunderline,	TkToverstrike,	TkTrelief,	TkTwrap,	TkTlineheight, 	TkTnumopts}; struct TkTline{	Point		orig;		/* where to put first item of line */	int		width;	int		height;	int		ascent;	int		flags;	TkTitem*	items;	TkTline*	next;	TkTline*	prev;}; struct TkText{	TkTline		start;		/* fake before-the-first line */	TkTline		end;		/* fake after-the-last line */	Tk*			tagshare;	TkTtabstop*	tabs;	TkTtaginfo*	tags;	TkTmarkinfo*	marks;	char*		xscroll;	char*		yscroll;	uchar		selunit;	/* select adjustment unit */	uchar		tflag;		/* various text-specific flags */	int			nlines;	/* number of nl items in widget */	TkTitem*	selfirst;	/* first item marked with sel tag */	TkTitem*	sellast;	/* item after last marked with sel tag */	Point		deltatv;	/* vector from text-space to view-space */	Point		deltaiv;	/* vector from image-space to view-space */	Point		current;	/* last known mouse pos */	Point		track;	/* for use when B1 or B2 is down */	int		nexttag;	/* next usable tag index */	TkTitem*	mouse;		/* mouse focus */	int		inswidth;	/* width of insertion cursor */	int		sborderwidth;	int		opts[TkTnumopts];	int		propagate;	int		scrolltop[2];	int		scrollbot[2];	Image*		image;	uchar		cur_flag;	/* text cursor to be shown up? */	Rectangle	cur_rec;	/* last text cursor rectangle */}; struct TkTwind{	Tk*		sub;		/* Subwindow of canvas */	Tk*		focus;		/* Current Mouse focus */	int		width;		/* current internal width */	int		height;		/* current internal height */	int		owned;	/* true if window is destroyed on item deletion */	int		align;		/* how to align within line */	char*		create;		/* creation script */	int		padx;		/* extra space on each side */	int		pady;		/* extra space on top and bot */	int		ascent;		/* distance from top of widget to baseline */	int		stretch;	/* true if need to stretch height */}; struct TkTitem{	uchar		kind;		/* e.g. TkTascii, etc */	uchar		tagextra;	short		width;	TkTitem		*next;	union	{		char*		string;		TkTwind*	win;		TkTmarkinfo*	mark;		TkTline*	line;	} u;	ulong		tags[1];	/* TkTitem length extends tagextra ulongs beyond */}; struct TkTmarkinfo{	char*		name;	int		gravity;	TkTitem*	cur;	TkTmarkinfo*	next;}; struct TkTtaginfo{	int		id;	char*		name;	TkEnv*		env;	TkTtabstop*	tabs;	TkTtaginfo*	next;	TkAction*	binds;		/* Binding of current events */	int		opts[TkTnumopts];}; struct TkTindex{	TkTitem*	item;	TkTline*	line;	int		pos;		/* index within multichar item */}; extern	TkCmdtab	tkttagcmd[];extern	TkCmdtab	tktmarkcmd[];extern	TkCmdtab	tktwincmd[]; extern	void		tkfreetext(Tk*);extern	char*		tktaddmarkinfo(TkText*, char*, TkTmarkinfo**);extern	char*		tktaddtaginfo(Tk*, char*, TkTtaginfo**);extern	int		tktadjustind(TkText*, int, TkTindex*);extern	int		tktanytags(TkTitem*);extern	Rectangle	tktbbox(Tk*, TkTindex*);extern	void		tktdirty(Tk*);extern	int		tktdispwidth(Tk*, TkTtabstop *tabs, TkTitem*, Font*, int, int, int);extern	void		tktendind(TkText*, TkTindex*);extern	char*	tktextcursor(Tk*, char*, char **);extern	Tk*		tktextevent(Tk*, int, void*);extern	Tk*		tktinwindow(Tk*, Point*);extern	char*		tktextselection(Tk*, char*, char**);extern	void		tktextsize(Tk*, int);extern	TkTmarkinfo*	tktfindmark(TkTmarkinfo*, char*);extern	int		tktfindsubitem(Tk*, TkTindex*);extern	TkTtaginfo*	tktfindtag(TkTtaginfo*, char*);extern	char*		tktfixgeom(Tk*, TkTline*, TkTline*, int);extern	void		tktfreeitems(TkText*, TkTitem*, int);extern	void		tktfreelines(TkText*, TkTline*, int);extern	void		tktfreemarks(TkTmarkinfo*);extern	void		tktfreetabs(TkTtabstop*);extern	void		tktfreetags(TkTtaginfo*);extern	int		tktindcompare(TkText*, TkTindex*, int, TkTindex*);extern	int		tktindbefore(TkTindex*, TkTindex*);extern	int		tktindrune(TkTindex*);extern	char*		tktinsert(Tk*, TkTindex*, char*, TkTitem*);extern	int	tktisbreak(int);extern	void		tktitemind(TkTitem*, TkTindex*);extern	char*		tktiteminsert(TkText*, TkTindex*, TkTitem*);extern	TkTline*	tktitemline(TkTitem*);extern	char*		tktindparse(Tk*, char**, TkTindex*);extern	TkTitem*	tktlastitem(TkTitem*);extern	int		tktlinenum(TkText*, TkTindex*);extern	int		tktlinepos(TkText*, TkTindex*);extern	int		tktmarkind(Tk*, char*, TkTindex*);extern	char*		tktmarkmove(Tk*, TkTmarkinfo*, TkTindex*);extern	char*		tktmarkparse(Tk*, char**, TkTmarkinfo**);extern	int		tktmaxwid(TkTline*);extern	char*		tktnewitem(int, int, TkTitem**);extern	char*		tktnewline(int, TkTitem*, TkTline*, TkTline*, TkTline**);extern	int		tktposcount(TkTitem*);extern	TkTline*	tktprevwrapline(Tk*, TkTline*);extern	void		tktremitem(TkText*, TkTindex*);extern	int		tktsametags(TkTitem*, TkTitem*);extern	char*		tktsplititem(TkTindex*);extern	void		tktstartind(TkText*, TkTindex*);extern	char*		tkttagchange(Tk*, int, TkTindex*, TkTindex*, int);extern	int		tkttagbit(TkTitem*, int, int);extern	void		tkttagcomb(TkTitem*, TkTitem*, int);extern	int		tkttagind(Tk*, char*, int, TkTindex*);extern	char*		tkttagname(TkText*, int);extern	int		tkttagnrange(TkText*, int, TkTindex*, TkTindex*, TkTindex*, TkTindex*);extern	void		tkttagopts(Tk*, TkTitem*, int*, TkEnv*, TkTtabstop **, int);extern	char*		tkttagparse(Tk*, char**, TkTtaginfo**);extern	int		tkttagset(TkTitem*, int);extern	int		tktxyind(Tk*, int, int, TkTindex*);extern	void		tktxtforgetsub(Tk*, Tk*);