/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include	"mk.h" static	int	bquote(Biobuf*, Bufblock*); /* *	Assemble a line skipping blank lines, comments, and eliding *	escaped newlines */intassline(Biobuf *bp, Bufblock *buf){	int c;	int lastc; 	buf->current=buf->start;	while ((c = nextrune(bp, 1)) >= 0){		switch(c)		{		case '\r':		/* consumes CRs for Win95 */			continue;		case '\n':			if (buf->current != buf->start) {				insert(buf, 0);				return 1;			}			break;		/* skip empty lines */		case '\\':		case '\'':		case '"':			rinsert(buf, c);			if (escapetoken(bp, buf, 1, c) == 0)				Exit();			break;		case '`':			if (bquote(bp, buf) == 0)				Exit();			break;		case '#':			lastc = '#';			while ((c = Bgetc(bp)) != '\n') {				if (c < 0)					goto eof;				if(c != '\r')					lastc = c;			}			mkinline++;			if (lastc == '\\')				break;		/* propagate escaped newlines??*/			if (buf->current != buf->start) {				insert(buf, 0);				return 1;			}			break;		default:			rinsert(buf, c);			break;		}	}eof:	insert(buf, 0);	return *buf->start != 0;} /* *	assemble a back-quoted shell command into a buffer */static intbquote(Biobuf *bp, Bufblock *buf){	int c, line, term;	int start; 	line = mkinline;	while((c = Bgetrune(bp)) == ' ' || c == '\t')			;	if(c == '{'){		term = '}';		/* rc style */		while((c = Bgetrune(bp)) == ' ' || c == '\t')			;	} else		term = '`';		/* sh style */ 	start = buf->current-buf->start;	for(;c > 0; c = nextrune(bp, 0)){		if(c == term){			insert(buf, '\n');			insert(buf,0);			buf->current = buf->start+start;			execinit();			execsh(0, buf->current, buf, envy);			return 1;		}		if(c == '\n')			break;		if(c == '\'' || c == '"' || c == '\\'){			insert(buf, c);			if(!escapetoken(bp, buf, 1, c))				return 0;			continue;		}		rinsert(buf, c);	}	SYNERR(line);	fprint(2, "missing closing %c after `\n", term);	return 0;} /* *	get next character stripping escaped newlines *	the flag specifies whether escaped newlines are to be elided or *	replaced with a blank. */intnextrune(Biobuf *bp, int elide){	int c; 	for (;;) {		c = Bgetrune(bp);		if (c == '\\') {			if (Bgetrune(bp) == '\n') {				mkinline++;				if (elide)					continue;				return ' ';			}			Bungetrune(bp);		}		if (c == '\n')			mkinline++;		return c;	}}