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#include	"mk.h"
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static	int	bquote(Biobuf*, Bufblock*);
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/*
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 *	Assemble a line skipping blank lines, comments, and eliding
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 *	escaped newlines
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 */
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int
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assline(Biobuf *bp, Bufblock *buf)
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{
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	int c;
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	int lastc;
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	buf->current=buf->start;
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	while ((c = nextrune(bp, 1)) >= 0){
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		switch(c)
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		{
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		case '\r':		/* consumes CRs for Win95 */
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			continue;
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		case '\n':
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			if (buf->current != buf->start) {
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				insert(buf, 0);
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				return 1;
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			}
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			break;		/* skip empty lines */
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		case '\\':
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		case '\'':
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		case '"':
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			rinsert(buf, c);
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			if (escapetoken(bp, buf, 1, c) == 0)
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				Exit();
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			break;
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		case '`':
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			if (bquote(bp, buf) == 0)
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				Exit();
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			break;
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		case '#':
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			lastc = '#';
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			while ((c = Bgetc(bp)) != '\n') {
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				if (c < 0)
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					goto eof;
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				if(c != '\r')
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					lastc = c;
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			}
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			mkinline++;
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			if (lastc == '\\')
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				break;		/* propagate escaped newlines??*/
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			if (buf->current != buf->start) {
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				insert(buf, 0);
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				return 1;
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			}
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			break;
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		default:
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			rinsert(buf, c);
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			break;
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		}
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	}
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eof:
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	insert(buf, 0);
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	return *buf->start != 0;
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}
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/*
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 *	assemble a back-quoted shell command into a buffer
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 */
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static int
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bquote(Biobuf *bp, Bufblock *buf)
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{
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	int c, line, term;
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	int start;
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	line = mkinline;
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	while((c = Bgetrune(bp)) == ' ' || c == '\t')
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			;
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	if(c == '{'){
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		term = '}';		/* rc style */
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		while((c = Bgetrune(bp)) == ' ' || c == '\t')
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			;
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	} else
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		term = '`';		/* sh style */
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	start = buf->current-buf->start;
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	for(;c > 0; c = nextrune(bp, 0)){
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		if(c == term){
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			insert(buf, '\n');
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			insert(buf,0);
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			buf->current = buf->start+start;
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			execinit();
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			execsh(0, buf->current, buf, envy);
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			return 1;
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		}
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		if(c == '\n')
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			break;
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		if(c == '\'' || c == '"' || c == '\\'){
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			insert(buf, c);
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			if(!escapetoken(bp, buf, 1, c))
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				return 0;
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			continue;
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		}
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		rinsert(buf, c);
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	}
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	SYNERR(line);
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	fprint(2, "missing closing %c after `\n", term);
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	return 0;
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}
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/*
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 *	get next character stripping escaped newlines
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 *	the flag specifies whether escaped newlines are to be elided or
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 *	replaced with a blank.
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 */
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int
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nextrune(Biobuf *bp, int elide)
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{
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	int c;
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	for (;;) {
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		c = Bgetrune(bp);
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		if (c == '\\') {
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			if (Bgetrune(bp) == '\n') {
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				mkinline++;
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				if (elide)
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					continue;
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				return ' ';
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			}
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			Bungetrune(bp);
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		}
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		if (c == '\n')
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			mkinline++;
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		return c;
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	}
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}