#include <u.h>#include <libc.h>#include <bio.h> char	buf[4096];Biobuf	bout; void	id(char*, int, ulong, ulong); voidmain(int argc, char *argv[]){	int fd;	char *e, *p, *q, *type;	ulong q0, q1; 	type = 0;	Binit(&bout, 1, OWRITE);	ARGBEGIN{	case 'c':		type =  "abcdefghijklmnopqrstuvwxyz_"			"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";		break;	case 'a':		type =  "abcdefghijklmnopqrstuvwxyz"			"ABCDEFGHIJKLMNOPQRSTUVWXYZ";		break;	case '0':		type =  "0123456789";		break;	default:		fprint(2, "usage: parse [-(ca0)]\n");		exits("usage");	}ARGEND	e = getenv("helpsel");	if(e){		p = utfrune(e, ':');		if(p && p>e && p[1]=='#'){			*p++ = 0;			q0 = strtoul(p+1, &q, 0);			q1 = q0;			if(q[0]==',' && q[1]=='#')				q1 = strtoul(q+2, 0, 0);			q1 -= q0;			if(q1 > sizeof buf-1)				q1 = sizeof buf-1;			sprint(buf, "/mnt/help/%s", e);			fd = open(buf, OREAD);			if(fd >= 0)				id(type, fd, q0, q1);		}	}	e = getenv("helpline");	if(e){		p = utfrune(e, ':');		if(p){			q = p;			*p++ = 0;			if(*e)				Bprint(&bout, "file='%s' ", e);			while(q>e && q[-1]!='/')				--q;			if(*q)				Bprint(&bout, "base='%s' ", q);			if(q == e)				Bprint(&bout, "dir=. ");			else{				while(q>e && q[-1]=='/')					--q;				if(q == e)					Bprint(&bout, "dir=/ ");				else{					*q = 0;					Bprint(&bout, "dir=%s ", e);				}			}			Bprint(&bout, "line=%s", p);		}	}	Bprint(&bout, "\n");} voidid(char *type, int fd, ulong p, ulong n){	long q;	char *b, *e; 	if(n>0 || type==0){		seek(fd, p, 0);		n = read(fd, buf, n);		if(n > 0){			buf[n] = 0;			Bprint(&bout, "id='%s' ", buf);		}		close(fd);		return;	} 	/*	 * back up a little	 */	q = p - 128;	if(q < 0)		q = 0;	seek(fd, q, 0); 	/*	 * now read a little and look for the identifier	 */	p -= q;	n = read(fd, buf, 256);	if(n < p)		return;	buf[n] = 0;	for(b=&buf[p]; b>buf; b--)		if(utfrune(type, b[-1]) == 0)			break;	for(e=&buf[p+1]; *e; e++)		if(utfrune(type, *e) == 0)			break;	*e = 0;	Bprint(&bout, "id='%s' ", b);	close(fd);}