diff -r 44a7194d00cf lib/yaccpar
--- a/lib/yaccpar	Sat Nov 12 11:52:10 2011 -0800
+++ b/lib/yaccpar	Tue Nov 15 13:10:13 2011 -0800
@@ -2,7 +2,7 @@
 #define YYERROR		goto yyerrlab
 #define YYACCEPT	return(0)
 #define YYABORT		return(1)
-#define	yyclearin	yychar = -1
+#define	yyclearin	yychar = YYEMPTY
 #define	yyerrok		yyerrflag = 0

 #ifdef	yydebug
@@ -51,6 +51,8 @@
 	return x;
 }

+long yychar;
+
 static long
 #ifdef YYARG
 yylex1(struct Yyarg *yyarg)
@@ -58,7 +60,6 @@
 yylex1(void)
 #endif
 {
-	long yychar;
 	const long *t3p;
 	int c;

@@ -68,6 +69,7 @@
 	yychar = yylex();
 #endif
 	if(yychar <= 0) {
+		yychar = 0;
 		c = yytok1[0];
 		goto out;
 	}
@@ -99,6 +101,8 @@
 	return c;
 }

+int yystate;
+
 int
 #ifdef YYARG
 yyparse(struct Yyarg *yyarg)
@@ -112,8 +116,8 @@
 		int	yys;
 	} yys[YYMAXDEPTH], *yyp, *yypt;
 	const short *yyxi;
-	int yyj, yym, yystate, yyn, yyg;
-	long yychar;
+	int yyj, yym, yyn, yyg;
+	long yyc;
 #ifndef YYARG
 	YYSTYPE save1, save2;
 	int save3, save4;
@@ -125,7 +129,8 @@
 #endif

 	yystate = 0;
-	yychar = -1;
+	yychar = YYEMPTY;
+	yyc = YYEMPTY;
 	yynerrs = 0;
 	yyerrflag = 0;
 	yyp = &yys[-1];
@@ -151,7 +156,7 @@
 yystack:
 	/* put a state and value onto the stack */
 	if(yydebug >= 4)
-		fprint(2, "char %s in %s", yytokname(yychar), yystatname(yystate));
+		fprint(2, "char %s in %s", yytokname(yyc), yystatname(yystate));

 	yyp++;
 	if(yyp >= &yys[YYMAXDEPTH]) {
@@ -165,18 +170,19 @@
 	yyn = yypact[yystate];
 	if(yyn <= YYFLAG)
 		goto yydefault; /* simple state */
-	if(yychar < 0)
+	if(yyc < 0)
 #ifdef YYARG
-		yychar = yylex1(yyarg);
+		yyc = yylex1(yyarg);
 #else
-		yychar = yylex1();
+		yyc = yylex1();
 #endif
-	yyn += yychar;
+	yyn += yyc;
 	if(yyn < 0 || yyn >= YYLAST)
 		goto yydefault;
 	yyn = yyact[yyn];
-	if(yychk[yyn] == yychar) { /* valid shift */
-		yychar = -1;
+	if(yychk[yyn] == yyc) { /* valid shift */
+		yyc = YYEMPTY;
+		yychar = YYEMPTY;
 		yyval = yylval;
 		yystate = yyn;
 		if(yyerrflag > 0)
@@ -188,11 +194,11 @@
 	/* default state action */
 	yyn = yydef[yystate];
 	if(yyn == -2) {
-		if(yychar < 0)
+		if(yyc < 0)
 #ifdef YYARG
-		yychar = yylex1(yyarg);
+			yyc = yylex1(yyarg);
 #else
-		yychar = yylex1();
+			yyc = yylex1();
 #endif

 		/* look through exception table */
@@ -201,21 +207,24 @@
 				break;
 		for(yyxi += 2;; yyxi += 2) {
 			yyn = yyxi[0];
-			if(yyn < 0 || yyn == yychar)
+			if(yyn < 0 || yyn == yyc)
 				break;
 		}
 		yyn = yyxi[1];
-		if(yyn < 0)
+		if(yyn < 0) {
+			yyc = YYEMPTY;
+			yychar = YYEMPTY;
 			goto ret0;
+		}
 	}
 	if(yyn == 0) {
 		/* error ... attempt to resume parsing */
 		switch(yyerrflag) {
 		case 0:   /* brand new error */
 			yyerror("syntax error");
-			if(yydebug >= 1) {
+			if(yydebug >= 2) {
 				fprint(2, "%s", yystatname(yystate));
-				fprint(2, "saw %s\n", yytokname(yychar));
+				fprint(2, "saw %s\n", yytokname(yyc));
 			}
 			goto yyerrlab;
 		yyerrlab:
@@ -245,10 +254,11 @@

 		case 3:  /* no shift yet; clobber input char */
 			if(yydebug >= 2)
-				fprint(2, "error recovery discards %s\n", yytokname(yychar));
-			if(yychar == YYEOFCODE)
+				fprint(2, "error recovery discards %s\n", yytokname(yyc));
+			if(yyc == YYEOFCODE)
 				goto ret1;
-			yychar = -1;
+			yyc = YYEMPTY;
+			yychar = YYEMPTY;
 			goto yynewstate;   /* try again in the same state */
 		}
 	}
diff -r 44a7194d00cf src/cmd/yacc.c
--- a/src/cmd/yacc.c	Sat Nov 12 11:52:10 2011 -0800
+++ b/src/cmd/yacc.c	Tue Nov 15 13:10:13 2011 -0800
@@ -92,6 +92,7 @@
 	TYPEDEF,
 	TYPENAME,
 	UNION,
+	IGNORE,

 	ENDFILE		= 0,

@@ -319,6 +320,9 @@
 	"token",	TERM,
 	"type",		TYPEDEF,
 	"union",	UNION,
+
+	/* ignored bison directives */
+	"error-verbose",	IGNORE,
 	0,
 };

@@ -330,6 +334,7 @@
 char*	writem(int*);
 char*	symnam(int);
 void	summary(void);
+void	grammar(void);
 void	error(char*, ...);
 void	aryfil(int*, int, int);
 int	setunion(int*, int*);
@@ -388,6 +393,7 @@
 	cempty();		/* make a table of which nonterminals can match the empty string */
 	cpfir();		/* make a table of firsts of nonterminals */
 	stagen();		/* generate the states */
+	grammar();
 	output();		/* write the states and the tables */
 	go2out();
 	hideprod();
@@ -531,14 +537,14 @@
 		;
 	p = prdptr[-*p];
 	q = chcopy(sarr, nontrst[*p-NTBASE].name);
-	q = chcopy(q, ": ");
+	q = chcopy(q, ":");
 	for(;;) {
 		*q = ' ';
 		p++;
-		if(p == pp)
-			*q = '.';
 		q++;
 		*q = '\0';
+		if(p == pp)
+			q = chcopy(q, ". ");
 		i = *p;
 		if(i <= 0)
 			break;
@@ -550,7 +556,7 @@
 	/* an item calling for a reduction */
 	i = *pp;
 	if(i < 0 ) {
-		q = chcopy(q, "    (");
+		q = chcopy(q, "   (");
 		sprint(q, "%d)", -i);
 	}
 	return sarr;
@@ -562,12 +568,41 @@
 char*
 symnam(int i)
 {
-	char* cp;
+	return (i >= NTBASE)? nontrst[i-NTBASE].name: tokset[i].name;
+}

-	cp = (i >= NTBASE)? nontrst[i-NTBASE].name: tokset[i].name;
-	if(*cp == ' ')
-		cp++;
-	return cp;
+/*
+ * output the grammar rules on y.output
+ */
+void
+grammar(void)
+{
+	int i, j, n, prev;
+	int *p;
+
+	if(foutput == 0)
+		return;
+
+	Bprint(foutput, "\nGrammar\n");
+	prev = 0;
+	n = 0;
+	PLOOP(0, i) {
+		p = prdptr[i];
+		j = 0;
+		if(p[0] == prev)
+			Bprint(foutput, "\t%d \t|", n++);
+		else {
+			Bprint(foutput, "\n\t%d %s:", n++, symnam(p[0]));
+			if(p[1] <= 0)
+				Bprint(foutput, " /* empty */");
+		}
+		for(j = 1; p[j] > 0; j++) {
+			Bprint(foutput, " %s", symnam(p[j]));
+		}
+		Bputc(foutput, '\n');
+		prev = p[0];
+	}
+	Bprint(foutput, "\n");
 }

 /*
@@ -1173,10 +1208,17 @@
 }

 void
+usage(void)
+{
+	fprint(2, "usage: yacc [-Dn] [-vdS] [-o outputfile] [-s stem] grammar\n");
+	exits("usage");
+}
+
+void
 setup(int argc, char *argv[])
 {
 	long c, t;
-	int i, j, fd, lev, ty, ytab, *p;
+	int i, j, lev, ty, ytab, *p;
 	int vflag, dflag, stem;
 	char actnm[8], *stemc, *s, dirbuf[128];
 	Biobuf *fout;
@@ -1195,7 +1237,7 @@
 		vflag++;
 		break;
 	case 'D':
-		yydebug = ARGF();
+		yydebug = EARGF(usage());
 		break;
 	case 'a':
 		yyarg = 1;
@@ -1208,7 +1250,7 @@
 		break;
 	case 'o':
 		ytab++;
-		ytabc = ARGF();
+		ytabc = EARGF(usage());
 		break;
 	case 's':
 		stem++;
@@ -1221,18 +1263,11 @@
 		error("illegal option: %c", ARGC());
 	}ARGEND
 	openup(stemc, dflag, vflag, ytab, ytabc);
-	fout = dflag?fdefine:ftable;
-	if(yyarg){
+	if(yyarg)
 		Bprint(ftable, "#define\tYYARG\t1\n\n");
-	}
-	if((fd = mkstemp(ttempname)) >= 0){
-		tempname = ttempname;
-		ftemp = Bfdopen(fd, OWRITE);
-	}
-	if((fd = mkstemp(tactname)) >= 0){
-		actname = tactname;
-		faction = Bfdopen(fd, OWRITE);
-	}
+
+	ftemp = Bopen(tempname = mktemp(ttempname), OWRITE);
+	faction = Bopen(actname = mktemp(tactname), OWRITE);
 	if(ftemp == 0 || faction == 0)
 		error("cannot open temp file");
 	if(argc < 1)
@@ -1375,6 +1410,10 @@
 		t = gettok();
 		continue;

+	case IGNORE:
+		t = gettok();
+		continue;
+
 	default:
 		error("syntax error");
 	}
@@ -1396,8 +1435,11 @@
 		Bprint(ftable, "YYSTYPE	yylval;\n");
 		Bprint(ftable, "YYSTYPE	yyval;\n");
 	}else{
-		if(dflag)
+		fout = ftable;
+		if(dflag){
+			fout = fdefine;
 			Bprint(ftable, "#include \"%s.%s\"\n\n", stemc, FILED);
+		}
 		Bprint(fout, "struct Yyarg {\n");
 		Bprint(fout, "\tint\tyynerrs;\n");
 		Bprint(fout, "\tint\tyyerrflag;\n");
@@ -1406,6 +1448,7 @@
 		Bprint(fout, "\tYYSTYPE\tyylval;\n");
 		Bprint(fout, "};\n\n");
 	}
+
 	prdptr[0] = mem;

 	/* added production */
@@ -1552,6 +1595,7 @@
 	Bterm(faction);
 	Bprint(ftable, "#define YYEOFCODE %d\n", 1);
 	Bprint(ftable, "#define YYERRCODE %d\n", 2);
+	Bprint(ftable, "#define YYEMPTY (%d)\n", -2);
 }

 /*
@@ -1581,17 +1625,17 @@

 	/* establish value for token */
 	/* single character literal */
-	if(s[0] == ' ') {
+	if(s[0] == '\'') {
 		val = chartorune(&rune, &s[1]);
-		if(s[val+1] == 0) {
+		if(s[val+1] == '\'') {
 			val = rune;
 			goto out;
 		}
 	}

 	/* escape sequence */
-	if(s[0] == ' ' && s[1] == '\\') {
-		if(s[3] == 0) {
+	if(s[0] == '\'' && s[1] == '\\') {
+		if(s[3] == '\'') {
 			/* single character escape sequence */
 			switch(s[2]) {
 			case 'n':	val = '\n'; break;
@@ -1625,6 +1669,7 @@
 	val = extval++;

 out:
+	//print("%s = %d\n", s, val);
 	tokset[ntokens].value = val;
 	toklev[ntokens] = 0;
 	return ntokens;
@@ -1642,7 +1687,7 @@
 	for(i=ndefout; i<=ntokens; i++) {
 		/* non-literals */
 		c = tokset[i].name[0];
-		if(c != ' ' && c != '$') {
+		if(c != '\'' && c != '$') {
 			Bprint(ftable, "#define	%s	%d\n",
 				tokset[i].name, tokset[i].value);
 			if(fdefine)
@@ -1737,7 +1782,7 @@
 	case '"':
 	case '\'':
 		match = c;
-		tokname[0] = ' ';
+		tokname[0] = '\'';
 		i = 1;
 		for(;;) {
 			c = Bgetrune(finput);
@@ -1756,6 +1801,8 @@
 			if(i < NAMESIZE)
 				i += c;
 		}
+		tokname[i] = '\'';
+		i++;
 		break;

 	case '%':
@@ -1847,7 +1894,7 @@
 {
 	int i;

-	if(s[0] == ' ')
+	if(s[0] == '\'')
 		t = 0;
 	TLOOP(i)
 		if(!strcmp(s, tokset[i].name))
@@ -1915,6 +1962,7 @@
 void
 cpycode(void)
 {
+
 	long c;

 	c = Bgetrune(finput);
@@ -1956,17 +2004,22 @@

 	/* i is the number of lines skipped */
 	i = 0;
-	if(Bgetrune(finput) != '*')
+	c = Bgetrune(finput);
+	if(c == '/'){			/* C++ //: skip to end of line */
+		while((c = Bgetrune(finput)) != Beof)
+			if(c == '\n')
+				return 1;
+	}else if(c == '*'){		/* normal C comment */
+		while((c = Bgetrune(finput)) != Beof) {
+			while(c == '*')
+				if((c = Bgetrune(finput)) == '/')
+					return i;
+			if(c == '\n')
+				i++;
+		}
+	}else
 		error("illegal comment");
-	c = Bgetrune(finput);
-	while(c != Beof) {
-		while(c == '*')
-			if((c=Bgetrune(finput)) == '/')
-				return i;
-		if(c == '\n')
-			i++;
-		c = Bgetrune(finput);
-	}
+
 	error("EOF inside comment");
 	return 0;
 }
@@ -2094,22 +2147,30 @@
 		/* look for comments */
 		Bputrune(faction, c);
 		c = Bgetrune(finput);
-		if(c != '*')
+		switch(c) {
+		case '/':
+			while(c != Beof) {
+				if(c == '\n')
+					goto swt;
+				Bputrune(faction, c);
+				c = Bgetrune(finput);
+			}
+			break;
+		case '*':
+			while(c != Beof) {
+				while(c == '*') {
+					Bputrune(faction, c);
+					if((c = Bgetrune(finput)) == '/')
+						goto lcopy;
+				}
+				Bputrune(faction, c);
+				if(c == '\n')
+					lineno++;
+				c = Bgetrune(faction);
+			}
+			break;
+		default:
 			goto swt;
-
-		/* it really is a comment */
-		Bputrune(faction, c);
-		c = Bgetrune(finput);
-		while(c >= 0) {
-			while(c == '*') {
-				Bputrune(faction, c);
-				if((c=Bgetrune(finput)) == '/')
-					goto lcopy;
-			}
-			Bputrune(faction, c);
-			if(c == '\n')
-				lineno++;
-			c = Bgetrune(finput);
 		}
 		error("EOF inside comment");

@@ -2158,26 +2219,26 @@
 	char buf[256];

 	if(vflag) {
-		sprint(buf, "%s.%s", stem, FILEU);
+		snprint(buf, sizeof buf, "%s.%s", stem, FILEU);
 		foutput = Bopen(buf, OWRITE);
 		if(foutput == 0)
 			error("cannot open %s", buf);
 	}
 	if(yydebug) {
-		sprint(buf, "%s.%s", stem, FILEDEBUG);
+		snprint(buf, sizeof buf, "%s.%s", stem, FILEDEBUG);
 		if((fdebug = Bopen(buf, OWRITE)) == 0)
 			error("can't open %s", buf);
 	}
 	if(dflag) {
-		sprint(buf, "%s.%s", stem, FILED);
+		snprint(buf, sizeof buf, "%s.%s", stem, FILED);
 		fdefine = Bopen(buf, OWRITE);
 		if(fdefine == 0)
 			error("can't create %s", buf);
 	}
 	if(ytab == 0)
-		sprint(buf, "%s.%s", stem, OFILE);
+		snprint(buf, sizeof buf, "%s.%s", stem, OFILE);
 	else
-		strcpy(buf, ytabc);
+		strecpy(buf, buf+sizeof buf, ytabc);
 	ftable = Bopen(buf, OWRITE);
 	if(ftable == 0)
 		error("cannot open table file %s", buf);