typedef struct Addr	Addr;typedef struct Client	Client;typedef struct Page	Page;typedef struct Proc	Proc;typedef struct String	String;typedef struct Text	Text; #define	NSTACK	1024 struct Proc{	jmp_buf	label;	Proc	*nextrun;		/* next in runqueue order */	Proc	*next;			/* next allocated */	Mouse	mouse;	int	dead;			/* flag */	void	*arg;	ulong	stack[NSTACK];}; struct String{	ushort	*s;		/* saved text */	ulong	n;		/* size of saved text */	ulong	nmax;		/* allocated size of text */}; struct Text{	Frame;	String;	long	org;		/* posn of first visible char */	long	q0;		/* selection */	long	q1;	int	outline;	/* selection should be outlined */	Page	*page;		/* containing page */	Rectangle scrollr;	/* locn of scroll bar */}; struct Page{	Page	*next;		/* in current list */	Page	*down;		/* head of list at next level down */	int	id;		/* unique identifier */	int	n;		/* tab number */	int	ntab;		/* next tab for sublist */	int	mod;		/* has been modified */	Rectangle r;	Rectangle subr;		/* rectangle containing subpages */	Rectangle tab;	Rectangle tabsr;	/* location of tabs for subpages */	Page	*parent;	/* p is in list at parent->down */	int	visible;	/* not hidden by other pages in list */	Text	tag;	Text	body;	Text	*text;		/* which Text mouse is inside */	int	ver;		/* parent of vertical list */	int	bdry;		/* y coord of division */	int	line1;		/* y coord of first line of text in body */}; struct Client{	int	ref;	int	slot;	int	busy;	Proc	*p;	char	*argv0;		/* name of process */	int	close;		/* shut down now */	uchar	*wbuf;		/* written data */	int	wcnt;	int	wfid;	String	*index;}; struct Addr{	int	valid;	long	q0;	long	q1;}; enum{	Ebadaddr,	Ebadctl,	Eclosed,	Eio,	Eisdir,	Enonexist,	Enopage,	Enotdir,	Eperm,	Eshutdown,	Eslot,	Egreg}; extern	Bitmap	*lightgrey;extern	Bitmap	*darkgrey;extern	Cursor	box; extern	struct proc{	Proc	*p;		/* running process */	Proc	*head;		/* next to run */	Proc	*tail;		/* tail of run queue */}proc; extern	int	cfd;		/* client end of pipe */extern	int	sfd;		/* service end of pipe */extern	int	clockfd;	/* /dev/time */extern	int	timefd;		/* /dev/cputime */ #define	NSLOT	32 #define	TABSZ		16#define	SCROLLWID	12#define	SCROLLGAP	(TABSZ-SCROLLWID) extern	Client	client[NSLOT];extern	Proc	*pmouse;extern	Proc	*pkbd;extern	int	kbdc;extern	struct mouse{	Mouse;	uchar	data[14];}mouse; extern	Page	*rootpage;extern	Page	*page;extern	Text	*curt;		/* current text with selection */extern	Text	*prevt;		/* previous text with selection */extern	char	user[NAMELEN];#define	GENBUFSIZE	4096extern	Rune	genbuf[GENBUFSIZE];extern	int	pageid;extern	long	clicktime;	/* ms since last click */