merged tcl 8.1 branch back into the main trunk

1 files changed, 1010 insertions, 0 deletions

diff --git a/generic/regc_lex.c b/generic/regc_lex.c
new file mode 100644
index 0000000..5b93e0b
--- /dev/null
+++ b/generic/regc_lex.c
@@ -0,0 +1,1010 @@
+/*
+ * lexical analyzer
+ * This file is #included by regcomp.c.
+ */
+
+/* scanning macros (know about v) */
+#define	ATEOS()		(v->now >= v->stop)
+#define	HAVE(n)		(v->stop - v->now >= (n))
+#define	NEXT1(c)	(!ATEOS() && *v->now == CHR(c))
+#define	NEXT2(a,b)	(HAVE(2) && *v->now == CHR(a) && *(v->now+1) == CHR(b))
+#define	NEXT3(a,b,c)	(HAVE(3) && *v->now == CHR(a) && \
+						*(v->now+1) == CHR(b) && \
+						*(v->now+2) == CHR(c))
+#define	SET(c)		(v->nexttype = (c))
+#define	SETV(c, n)	(v->nexttype = (c), v->nextvalue = (n))
+#define	RET(c)		return (SET(c), 1)
+#define	RETV(c, n)	return (SETV(c, n), 1)
+#define	FAILW(e)	return (ERR(e), 0)	/* ERR does SET(EOS) */
+#define	LASTTYPE(t)	(v->lasttype == (t))
+
+/* lexical contexts */
+#define	L_ERE	1	/* mainline ERE/ARE */
+#define	L_BRE	2	/* mainline BRE */
+#define	L_Q	3	/* REG_QUOTE */
+#define	L_EBND	4	/* ERE/ARE bound */
+#define	L_BBND	5	/* BRE bound */
+#define	L_BRACK	6	/* brackets */
+#define	L_CEL	7	/* collating element */
+#define	L_ECL	8	/* equivalence class */
+#define	L_CCL	9	/* character class */
+#define	INTOCON(c)	(v->lexcon = (c))
+#define	INCON(con)	(v->lexcon == (con))
+
+/* construct pointer past end of chr array */
+#define	ENDOF(array)	((array) + sizeof(array)/sizeof(chr))
+
+/*
+ - lexstart - set up lexical stuff, scan leading options
+ ^ static VOID lexstart(struct vars *);
+ */
+static VOID
+lexstart(v)
+struct vars *v;
+{
+	prefixes(v);			/* may turn on new type bits etc. */
+	NOERR();
+
+	if (v->cflags&REG_QUOTE) {
+		assert(!(v->cflags&(REG_ADVANCED|REG_EXPANDED|REG_NEWLINE)));
+		INTOCON(L_Q);
+	} else if (v->cflags&REG_EXTENDED) {
+		assert(!(v->cflags&REG_QUOTE));
+		INTOCON(L_ERE);
+	} else {
+		assert(!(v->cflags&(REG_QUOTE|REG_ADVF)));
+		INTOCON(L_BRE);
+	}
+
+	v->nexttype = EMPTY;		/* remember we were at the start */
+	next(v);			/* set up the first token */
+}
+
+/*
+ - prefixes - implement various special prefixes
+ ^ static VOID prefixes(struct vars *);
+ */
+static VOID
+prefixes(v)
+struct vars *v;
+{
+	/* literal string doesn't get any of this stuff */
+	if (v->cflags&REG_QUOTE)
+		return;
+
+	/* initial "***" gets special things */	
+	if (HAVE(4) && NEXT3('*', '*', '*'))
+		switch (*(v->now + 3)) {
+		case CHR('?'):		/* "***?" error, msg shows version */
+			ERR(REG_BADPAT);
+			return;		/* proceed no further */
+			break;
+		case CHR('='):		/* "***=" shifts to literal string */
+			NOTE(REG_UNONPOSIX);
+			v->cflags |= REG_QUOTE;
+			v->cflags &= ~(REG_ADVANCED|REG_EXPANDED|REG_NEWLINE);
+			v->now += 4;
+			return;		/* and there can be no more prefixes */
+			break;
+		case CHR(':'):		/* "***:" shifts to AREs */
+			NOTE(REG_UNONPOSIX);
+			v->cflags |= REG_ADVANCED;
+			v->now += 4;
+			break;
+		default:		/* otherwise *** is just an error */
+			ERR(REG_BADRPT);
+			return;
+			break;
+		}
+
+	/* BREs and EREs don't get embedded options */
+	if ((v->cflags&REG_ADVANCED) != REG_ADVANCED)
+		return;
+
+	/* embedded options (AREs only) */
+	if (HAVE(3) && NEXT2('(', '?') && iscalpha(*(v->now + 2))) {
+		NOTE(REG_UNONPOSIX);
+		v->now += 2;
+		for (; !ATEOS() && iscalpha(*v->now); v->now++)
+			switch (*v->now) {
+			case CHR('b'):		/* BREs (but why???) */
+				v->cflags &= ~(REG_ADVANCED|REG_QUOTE);
+				break;
+			case CHR('c'):		/* case sensitive */
+				v->cflags &= ~REG_ICASE;
+				break;
+			case CHR('e'):		/* plain EREs */
+				v->cflags |= REG_EXTENDED;
+				v->cflags &= ~(REG_ADVF|REG_QUOTE);
+				break;
+			case CHR('i'):		/* case insensitive */
+				v->cflags |= REG_ICASE;
+				break;
+			case CHR('m'):		/* Perloid synonym for n */
+			case CHR('n'):		/* \n affects ^ $ . [^ */
+				v->cflags |= REG_NEWLINE;
+				break;
+			case CHR('p'):		/* ~Perl, \n affects . [^ */
+				v->cflags |= REG_NLSTOP;
+				v->cflags &= ~REG_NLANCH;
+				break;
+			case CHR('q'):		/* literal string */
+				v->cflags |= REG_QUOTE;
+				v->cflags &= ~REG_ADVANCED;
+				break;
+			case CHR('s'):		/* single line, \n ordinary */
+				v->cflags &= ~REG_NEWLINE;
+				break;
+			case CHR('t'):		/* tight syntax */
+				v->cflags &= ~REG_EXPANDED;
+				break;
+			case CHR('w'):		/* weird, \n affects ^ $ only */
+				v->cflags &= ~REG_NLSTOP;
+				v->cflags |= REG_NLANCH;
+				break;
+			case CHR('x'):		/* expanded syntax */
+				v->cflags |= REG_EXPANDED;
+				break;
+			default:
+				ERR(REG_BADOPT);
+				return;
+			}
+		if (!NEXT1(')')) {
+			ERR(REG_BADOPT);
+			return;
+		}
+		v->now++;
+		if (v->cflags&REG_QUOTE)
+			v->cflags &= ~(REG_EXPANDED|REG_NEWLINE);
+	}
+}
+
+/*
+ - lexnest - "call a subroutine", interpolating string at the lexical level
+ * Note, this is not a very general facility.  There are a number of
+ * implicit assumptions about what sorts of strings can be subroutines.
+ ^ static VOID lexnest(struct vars *, chr *, chr *);
+ */
+static VOID
+lexnest(v, beginp, endp)
+struct vars *v;
+chr *beginp;				/* start of interpolation */
+chr *endp;				/* one past end of interpolation */
+{
+	assert(v->savenow == NULL);	/* only one level of nesting */
+	v->savenow = v->now;
+	v->savestop = v->stop;
+	v->now = beginp;
+	v->stop = endp;
+}
+
+/*
+ * string constants to interpolate as expansions of things like \d
+ */
+static chr backd[] = {		/* \d */
+	CHR('['), CHR('['), CHR(':'),
+	CHR('d'), CHR('i'), CHR('g'), CHR('i'), CHR('t'),
+	CHR(':'), CHR(']'), CHR(']')
+};
+static chr backD[] = {		/* \D */
+	CHR('['), CHR('^'), CHR('['), CHR(':'),
+	CHR('d'), CHR('i'), CHR('g'), CHR('i'), CHR('t'),
+	CHR(':'), CHR(']'), CHR(']')
+};
+static chr brbackd[] = {	/* \d within brackets */
+	CHR('['), CHR(':'),
+	CHR('d'), CHR('i'), CHR('g'), CHR('i'), CHR('t'),
+	CHR(':'), CHR(']')
+};
+static chr backs[] = {		/* \s */
+	CHR('['), CHR('['), CHR(':'),
+	CHR('s'), CHR('p'), CHR('a'), CHR('c'), CHR('e'),
+	CHR(':'), CHR(']'), CHR(']')
+};
+static chr backS[] = {		/* \S */
+	CHR('['), CHR('^'), CHR('['), CHR(':'),
+	CHR('s'), CHR('p'), CHR('a'), CHR('c'), CHR('e'),
+	CHR(':'), CHR(']'), CHR(']')
+};
+static chr brbacks[] = {	/* \s within brackets */
+	CHR('['), CHR(':'),
+	CHR('s'), CHR('p'), CHR('a'), CHR('c'), CHR('e'),
+	CHR(':'), CHR(']')
+};
+static chr backw[] = {		/* \w */
+	CHR('['), CHR('['), CHR(':'),
+	CHR('a'), CHR('l'), CHR('n'), CHR('u'), CHR('m'),
+	CHR(':'), CHR(']'), CHR('_'), CHR(']')
+};
+static chr backW[] = {		/* \W */
+	CHR('['), CHR('^'), CHR('['), CHR(':'),
+	CHR('a'), CHR('l'), CHR('n'), CHR('u'), CHR('m'),
+	CHR(':'), CHR(']'), CHR('_'), CHR(']')
+};
+static chr brbackw[] = {	/* \w within brackets */
+	CHR('['), CHR(':'),
+	CHR('a'), CHR('l'), CHR('n'), CHR('u'), CHR('m'),
+	CHR(':'), CHR(']'), CHR('_')
+};
+
+/*
+ - lexword - interpolate a bracket expression for word characters
+ * Possibly ought to inquire whether there is a "word" character class.
+ ^ static VOID lexword(struct vars *);
+ */
+static VOID
+lexword(v)
+struct vars *v;
+{
+	lexnest(v, backw, ENDOF(backw));
+}
+
+/*
+ - next - get next token
+ ^ static int next(struct vars *);
+ */
+static int			/* 1 normal, 0 failure */
+next(v)
+struct vars *v;
+{
+	chr c;
+
+	/* errors yield an infinite sequence of failures */
+	if (ISERR())
+		return 0;	/* the error has set nexttype to EOS */
+
+	/* remember flavor of last token */
+	v->lasttype = v->nexttype;
+
+	/* if we're nested and we've hit end, return to outer level */
+	if (v->savenow != NULL && ATEOS()) {
+		v->now = v->savenow;
+		v->stop = v->savestop;
+		v->savenow = v->savestop = NULL;
+	}
+
+	/* skip white space etc. if appropriate (not in literal or []) */
+	if (v->cflags&REG_EXPANDED)
+		switch (v->lexcon) {
+		case L_ERE:
+		case L_BRE:
+		case L_EBND:
+		case L_BBND:
+			skip(v);
+			break;
+		}
+
+	/* handle EOS, depending on context */
+	if (ATEOS()) {
+		switch (v->lexcon) {
+		case L_ERE:
+		case L_BRE:
+		case L_Q:
+			RET(EOS);
+			break;
+		case L_EBND:
+		case L_BBND:
+			FAILW(REG_EBRACE);
+			break;
+		case L_BRACK:
+		case L_CEL:
+		case L_ECL:
+		case L_CCL:
+			FAILW(REG_EBRACK);
+			break;
+		}
+		assert(NOTREACHED);
+	}
+
+	/* okay, time to actually get a character */
+	c = *v->now++;
+
+	/* deal with the easy contexts, punt EREs to code below */
+	switch (v->lexcon) {
+	case L_BRE:			/* punt BREs to separate function */
+		return brenext(v, c);
+		break;
+	case L_ERE:			/* see below */
+		break;
+	case L_Q:			/* literal strings are easy */
+		RETV(PLAIN, c);
+		break;
+	case L_BBND:			/* bounds are fairly simple */
+	case L_EBND:
+		switch (c) {
+		case CHR('0'): case CHR('1'): case CHR('2'): case CHR('3'):
+		case CHR('4'): case CHR('5'): case CHR('6'): case CHR('7'):
+		case CHR('8'): case CHR('9'):
+			RETV(DIGIT, (chr)DIGITVAL(c));
+			break;
+		case CHR(','):
+			RET(',');
+			break;
+		case CHR('}'):		/* ERE bound ends with } */
+			if (INCON(L_EBND)) {
+				INTOCON(L_ERE);
+				if ((v->cflags&REG_ADVF) && NEXT1('?')) {
+					v->now++;
+					NOTE(REG_UNONPOSIX);
+					RETV('}', 0);
+				}
+				RETV('}', 1);
+			} else
+				FAILW(REG_BADBR);
+			break;
+		case CHR('\\'):		/* BRE bound ends with \} */
+			if (INCON(L_BBND) && NEXT1('}')) {
+				v->now++;
+				INTOCON(L_BRE);
+				RET('}');
+			} else
+				FAILW(REG_BADBR);
+			break;
+		default:
+			FAILW(REG_BADBR);
+			break;
+		}
+		assert(NOTREACHED);
+		break;
+	case L_BRACK:			/* brackets are not too hard */
+		switch (c) {
+		case CHR(']'):
+			if (LASTTYPE('['))
+				RETV(PLAIN, c);
+			else {
+				INTOCON((v->cflags&REG_EXTENDED) ?
+							L_ERE : L_BRE);
+				RET(']');
+			}
+			break;
+		case CHR('\\'):
+			NOTE(REG_UBBS);
+			if (!(v->cflags&REG_ADVF))
+				RETV(PLAIN, c);
+			NOTE(REG_UNONPOSIX);
+			if (ATEOS())
+				FAILW(REG_EESCAPE);
+			(DISCARD)lexescape(v);
+			switch (v->nexttype) {	/* not all escapes okay here */
+			case PLAIN:
+				return 1;
+				break;
+			case CCLASS:
+				switch (v->nextvalue) {
+				case 'd':
+					lexnest(v, brbackd, ENDOF(brbackd));
+					break;
+				case 's':
+					lexnest(v, brbacks, ENDOF(brbacks));
+					break;
+				case 'w':
+					lexnest(v, brbackw, ENDOF(brbackw));
+					break;
+				default:
+					FAILW(REG_EESCAPE);
+					break;
+				}
+				/* lexnest done, back up and try again */
+				v->nexttype = v->lasttype;
+				return next(v);
+				break;
+			}
+			/* not one of the acceptable escapes */
+			FAILW(REG_EESCAPE);
+			break;
+		case CHR('-'):
+			if (LASTTYPE('[') || NEXT1(']'))
+				RETV(PLAIN, c);
+			else
+				RETV(RANGE, c);
+			break;
+		case CHR('['):
+			if (ATEOS())
+				FAILW(REG_EBRACK);
+			switch (*v->now++) {
+			case CHR('.'):
+				INTOCON(L_CEL);
+				/* might or might not be locale-specific */
+				RET(COLLEL);
+				break;
+			case CHR('='):
+				INTOCON(L_ECL);
+				NOTE(REG_ULOCALE);
+				RET(ECLASS);
+				break;
+			case CHR(':'):
+				INTOCON(L_CCL);
+				NOTE(REG_ULOCALE);
+				RET(CCLASS);
+				break;
+			default:			/* oops */
+				v->now--;
+				RETV(PLAIN, c);
+				break;
+			}
+			assert(NOTREACHED);
+			break;
+		default:
+			RETV(PLAIN, c);
+			break;
+		}
+		assert(NOTREACHED);
+		break;
+	case L_CEL:			/* collating elements are easy */
+		if (c == CHR('.') && NEXT1(']')) {
+			v->now++;
+			INTOCON(L_BRACK);
+			RETV(END, '.');
+		} else
+			RETV(PLAIN, c);
+		break;
+	case L_ECL:			/* ditto equivalence classes */
+		if (c == CHR('=') && NEXT1(']')) {
+			v->now++;
+			INTOCON(L_BRACK);
+			RETV(END, '=');
+		} else
+			RETV(PLAIN, c);
+		break;
+	case L_CCL:			/* ditto character classes */
+		if (c == CHR(':') && NEXT1(']')) {
+			v->now++;
+			INTOCON(L_BRACK);
+			RETV(END, ':');
+		} else
+			RETV(PLAIN, c);
+		break;
+	default:
+		assert(NOTREACHED);
+		break;
+	}
+
+	/* that got rid of everything except EREs and AREs */
+	assert(INCON(L_ERE));
+
+	/* deal with EREs and AREs, except for backslashes */
+	switch (c) {
+	case CHR('|'):
+		RET('|');
+		break;
+	case CHR('*'):
+		if ((v->cflags&REG_ADVF) && NEXT1('?')) {
+			v->now++;
+			NOTE(REG_UNONPOSIX);
+			RETV('*', 0);
+		}
+		RETV('*', 1);
+		break;
+	case CHR('+'):
+		if ((v->cflags&REG_ADVF) && NEXT1('?')) {
+			v->now++;
+			NOTE(REG_UNONPOSIX);
+			RETV('+', 0);
+		}
+		RETV('+', 1);
+		break;
+	case CHR('?'):
+		if ((v->cflags&REG_ADVF) && NEXT1('?')) {
+			v->now++;
+			NOTE(REG_UNONPOSIX);
+			RETV('?', 0);
+		}
+		RETV('?', 1);
+		break;
+	case CHR('{'):		/* bounds start or plain character */
+		if (v->cflags&REG_EXPANDED)
+			skip(v);
+		if (ATEOS() || !iscdigit(*v->now)) {
+			NOTE(REG_UBRACES);
+			NOTE(REG_UUNSPEC);
+			RETV(PLAIN, c);
+		} else {
+			NOTE(REG_UBOUNDS);
+			INTOCON(L_EBND);
+			RET('{');
+		}
+		assert(NOTREACHED);
+		break;
+	case CHR('('):		/* parenthesis, or advanced extension */
+		if ((v->cflags&REG_ADVF) && NEXT1('?')) {
+			NOTE(REG_UNONPOSIX);
+			v->now++;
+			switch (*v->now++) {
+			case CHR(':'):		/* non-capturing paren */
+				RETV('(', 0);
+				break;
+			case CHR('#'):		/* comment */
+				while (!ATEOS() && *v->now != CHR(')'))
+					v->now++;
+				if (!ATEOS())
+					v->now++;
+				assert(v->nexttype == v->lasttype);
+				return next(v);
+				break;
+			case CHR('='):		/* positive lookahead */
+				NOTE(REG_ULOOKAHEAD);
+				RETV(LACON, 1);
+				break;
+			case CHR('!'):		/* negative lookahead */
+				NOTE(REG_ULOOKAHEAD);
+				RETV(LACON, 0);
+				break;
+			default:
+				FAILW(REG_BADRPT);
+				break;
+			}
+			assert(NOTREACHED);
+		}
+		if (v->cflags&REG_NOSUB)
+			RETV('(', 0);		/* all parens non-capturing */
+		else
+			RETV('(', 1);
+		break;
+	case CHR(')'):
+		if (LASTTYPE('(')) {
+			NOTE(REG_UUNSPEC);
+		}
+		RETV(')', c);
+		break;
+	case CHR('['):		/* easy except for [[:<:]] and [[:>:]] */
+		if (HAVE(6) &&	*(v->now+0) == CHR('[') &&
+				*(v->now+1) == CHR(':') &&
+				(*(v->now+2) == CHR('<') ||
+						*(v->now+2) == CHR('>')) &&
+				*(v->now+3) == CHR(':') &&
+				*(v->now+4) == CHR(']') &&
+				*(v->now+5) == CHR(']')) {
+			c = *(v->now+2);
+			v->now += 6;
+			NOTE(REG_UNONPOSIX);
+			RET((c == CHR('<')) ? '<' : '>');
+		}
+		INTOCON(L_BRACK);
+		if (NEXT1('^')) {
+			v->now++;
+			RETV('[', 0);
+		}
+		RETV('[', 1);
+		break;
+	case CHR('.'):
+		RET('.');
+		break;
+	case CHR('^'):
+		RET('^');
+		break;
+	case CHR('$'):
+		RET('$');
+		break;
+	case CHR('\\'):		/* mostly punt backslashes to code below */
+		if (ATEOS())
+			FAILW(REG_EESCAPE);
+		break;
+	default:		/* ordinary character */
+		RETV(PLAIN, c);
+		break;
+	}
+
+	/* ERE/ARE backslash handling; backslash already eaten */
+	assert(!ATEOS());
+	if (!(v->cflags&REG_ADVF)) {	/* only AREs have non-trivial escapes */
+		if (iscalnum(*v->now)) {
+			NOTE(REG_UBSALNUM);
+			NOTE(REG_UUNSPEC);
+		}
+		RETV(PLAIN, *v->now++);
+	}
+	(DISCARD)lexescape(v);
+	if (ISERR())
+		FAILW(REG_EESCAPE);
+	if (v->nexttype == CCLASS) {	/* fudge at lexical level */
+		switch (v->nextvalue) {
+		case 'd':	lexnest(v, backd, ENDOF(backd)); break;
+		case 'D':	lexnest(v, backD, ENDOF(backD)); break;
+		case 's':	lexnest(v, backs, ENDOF(backs)); break;
+		case 'S':	lexnest(v, backS, ENDOF(backS)); break;
+		case 'w':	lexnest(v, backw, ENDOF(backw)); break;
+		case 'W':	lexnest(v, backW, ENDOF(backW)); break;
+		default:
+			assert(NOTREACHED);
+			FAILW(REG_ASSERT);
+			break;
+		}
+		/* lexnest done, back up and try again */
+		v->nexttype = v->lasttype;
+		return next(v);
+	}
+	/* otherwise, lexescape has already done the work */
+	return !ISERR();
+}
+
+/*
+ - lexescape - parse an ARE backslash escape (backslash already eaten)
+ * Note slightly nonstandard use of the CCLASS type code.
+ ^ static int lexescape(struct vars *);
+ */
+static int			/* not actually used, but convenient for RETV */
+lexescape(v)
+struct vars *v;
+{
+	chr c;
+	static chr alert[] = {
+		CHR('a'), CHR('l'), CHR('e'), CHR('r'), CHR('t')
+	};
+	static chr esc[] = {
+		CHR('E'), CHR('S'), CHR('C')
+	};
+	chr *save;
+
+	assert(v->cflags&REG_ADVF);
+
+	assert(!ATEOS());
+	c = *v->now++;
+	if (!iscalnum(c))
+		RETV(PLAIN, c);
+
+	NOTE(REG_UNONPOSIX);
+	switch (c) {
+	case CHR('a'):
+		RETV(PLAIN, chrnamed(v, alert, ENDOF(alert), CHR('\007')));
+		break;
+	case CHR('A'):
+		RETV(SBEGIN, 0);
+		break;
+	case CHR('b'):
+		RETV(PLAIN, CHR('\b'));
+		break;
+	case CHR('B'):
+		RETV(PLAIN, CHR('\\'));
+		break;
+	case CHR('c'):
+		NOTE(REG_UUNPORT);
+		if (ATEOS())
+			FAILW(REG_EESCAPE);
+		RETV(PLAIN, (chr)(*v->now++ & 037));
+		break;
+	case CHR('d'):
+		NOTE(REG_ULOCALE);
+		RETV(CCLASS, 'd');
+		break;
+	case CHR('D'):
+		NOTE(REG_ULOCALE);
+		RETV(CCLASS, 'D');
+		break;
+	case CHR('e'):
+		NOTE(REG_UUNPORT);
+		RETV(PLAIN, chrnamed(v, esc, ENDOF(esc), CHR('\033')));
+		break;
+	case CHR('f'):
+		RETV(PLAIN, CHR('\f'));
+		break;
+	case CHR('m'):
+		RET('<');
+		break;
+	case CHR('M'):
+		RET('>');
+		break;
+	case CHR('n'):
+		RETV(PLAIN, CHR('\n'));
+		break;
+	case CHR('r'):
+		RETV(PLAIN, CHR('\r'));
+		break;
+	case CHR('s'):
+		NOTE(REG_ULOCALE);
+		RETV(CCLASS, 's');
+		break;
+	case CHR('S'):
+		NOTE(REG_ULOCALE);
+		RETV(CCLASS, 'S');
+		break;
+	case CHR('t'):
+		RETV(PLAIN, CHR('\t'));
+		break;
+	case CHR('u'):
+		c = lexdigits(v, 16, 4, 4);
+		if (ISERR())
+			FAILW(REG_EESCAPE);
+		RETV(PLAIN, c);
+		break;
+	case CHR('U'):
+		c = lexdigits(v, 16, 8, 8);
+		if (ISERR())
+			FAILW(REG_EESCAPE);
+		RETV(PLAIN, c);
+		break;
+	case CHR('v'):
+		RETV(PLAIN, CHR('\v'));
+		break;
+	case CHR('w'):
+		NOTE(REG_ULOCALE);
+		RETV(CCLASS, 'w');
+		break;
+	case CHR('W'):
+		NOTE(REG_ULOCALE);
+		RETV(CCLASS, 'W');
+		break;
+	case CHR('x'):
+		NOTE(REG_UUNPORT);
+		c = lexdigits(v, 16, 1, 255);	/* REs >255 long outside spec */
+		if (ISERR())
+			FAILW(REG_EESCAPE);
+		RETV(PLAIN, c);
+		break;
+	case CHR('y'):
+		NOTE(REG_ULOCALE);
+		RETV(WBDRY, 0);
+		break;
+	case CHR('Y'):
+		NOTE(REG_ULOCALE);
+		RETV(NWBDRY, 0);
+		break;
+	case CHR('Z'):
+		RETV(SEND, 0);
+		break;
+	case CHR('1'): case CHR('2'): case CHR('3'): case CHR('4'):
+	case CHR('5'): case CHR('6'): case CHR('7'): case CHR('8'):
+	case CHR('9'):
+		save = v->now;
+		v->now--;	/* put first digit back */
+		c = lexdigits(v, 10, 1, 255);	/* REs >255 long outside spec */
+		if (ISERR())
+			FAILW(REG_EESCAPE);
+		/* ugly heuristic (first test is "exactly 1 digit?") */
+		if (v->now - save == 0 || (int)c <= v->nsubexp) {
+			NOTE(REG_UBACKREF);
+			RETV(BACKREF, (chr)c);
+		}
+		/* oops, doesn't look like it's a backref after all... */
+		v->now = save;
+		/* and fall through into octal number */
+	case CHR('0'):
+		NOTE(REG_UUNPORT);
+		v->now--;	/* put first digit back */
+		c = lexdigits(v, 8, 1, 3);
+		if (ISERR())
+			FAILW(REG_EESCAPE);
+		RETV(PLAIN, c);
+		break;
+	default:
+		assert(iscalpha(c));
+		FAILW(REG_EESCAPE);	/* unknown alphabetic escape */
+		break;
+	}
+	assert(NOTREACHED);
+}
+
+/*
+ - lexdigits - slurp up digits and return chr value
+ ^ static chr lexdigits(struct vars *, int, int, int);
+ */
+static chr			/* chr value; errors signalled via ERR */
+lexdigits(v, base, minlen, maxlen)
+struct vars *v;
+int base;
+int minlen;
+int maxlen;
+{
+	uchr n;			/* unsigned to avoid overflow misbehavior */
+	int len;
+	chr c;
+	int d;
+	CONST uchr ub = (uchr) base;
+
+	n = 0;
+	for (len = 0; len < maxlen && !ATEOS(); len++) {
+		c = *v->now++;
+		switch (c) {
+		case CHR('0'): case CHR('1'): case CHR('2'): case CHR('3'):
+		case CHR('4'): case CHR('5'): case CHR('6'): case CHR('7'):
+		case CHR('8'): case CHR('9'):
+			d = DIGITVAL(c);
+			break;
+		case CHR('a'): case CHR('A'): d = 10; break;
+		case CHR('b'): case CHR('B'): d = 11; break;
+		case CHR('c'): case CHR('C'): d = 12; break;
+		case CHR('d'): case CHR('D'): d = 13; break;
+		case CHR('e'): case CHR('E'): d = 14; break;
+		case CHR('f'): case CHR('F'): d = 15; break;
+		default:
+			v->now--;	/* oops, not a digit at all */
+			d = -1;
+			break;
+		}
+
+		if (d >= base) {	/* not a plausible digit */
+			v->now--;
+			d = -1;
+		}
+		if (d < 0)
+			break;		/* NOTE BREAK OUT */
+		n = n*ub + (uchr)d;
+	}
+	if (len < minlen)
+		ERR(REG_EESCAPE);
+
+	return (chr)n;
+}
+
+/*
+ - brenext - get next BRE token
+ * This is much like EREs except for all the stupid backslashes and the
+ * context-dependency of some things.
+ ^ static int brenext(struct vars *, pchr);
+ */
+static int			/* 1 normal, 0 failure */
+brenext(v, pc)
+struct vars *v;
+pchr pc;
+{
+	chr c = (chr)pc;
+
+	switch (c) {
+	case CHR('*'):
+		if (LASTTYPE(EMPTY) || LASTTYPE('(') || LASTTYPE('^'))
+			RETV(PLAIN, c);
+		RET('*');
+		break;
+	case CHR('['):
+		if (HAVE(6) &&	*(v->now+0) == CHR('[') &&
+				*(v->now+1) == CHR(':') &&
+				(*(v->now+2) == CHR('<') ||
+						*(v->now+2) == CHR('>')) &&
+				*(v->now+3) == CHR(':') &&
+				*(v->now+4) == CHR(']') &&
+				*(v->now+5) == CHR(']')) {
+			c = *(v->now+2);
+			v->now += 6;
+			NOTE(REG_UNONPOSIX);
+			RET((c == CHR('<')) ? '<' : '>');
+		}
+		INTOCON(L_BRACK);
+		if (NEXT1('^')) {
+			v->now++;
+			RETV('[', 0);
+		}
+		RETV('[', 1);
+		break;
+	case CHR('.'):
+		RET('.');
+		break;
+	case CHR('^'):
+		if (LASTTYPE(EMPTY))
+			RET('^');
+		if (LASTTYPE('(')) {
+			NOTE(REG_UUNSPEC);
+			RET('^');
+		}
+		RETV(PLAIN, c);
+		break;
+	case CHR('$'):
+		if (v->cflags&REG_EXPANDED)
+			skip(v);
+		if (ATEOS())
+			RET('$');
+		if (NEXT2('\\', ')')) {
+			NOTE(REG_UUNSPEC);
+			RET('$');
+		}
+		RETV(PLAIN, c);
+		break;
+	case CHR('\\'):
+		break;		/* see below */
+	default:
+		RETV(PLAIN, c);
+		break;
+	}
+
+	assert(c == CHR('\\'));
+
+	if (ATEOS())
+		FAILW(REG_EESCAPE);
+
+	c = *v->now++;
+	switch (c) {
+	case CHR('{'):
+		INTOCON(L_BBND);
+		NOTE(REG_UBOUNDS);
+		RET('{');
+		break;
+	case CHR('('):
+		RETV('(', 1);
+		break;
+	case CHR(')'):
+		RETV(')', c);
+		break;
+	case CHR('<'):
+		NOTE(REG_UNONPOSIX);
+		RET('<');
+		break;
+	case CHR('>'):
+		NOTE(REG_UNONPOSIX);
+		RET('>');
+		break;
+	case CHR('1'): case CHR('2'): case CHR('3'): case CHR('4'):
+	case CHR('5'): case CHR('6'): case CHR('7'): case CHR('8'):
+	case CHR('9'):
+		NOTE(REG_UBACKREF);
+		RETV(BACKREF, (chr)DIGITVAL(c));
+		break;
+	default:
+		if (iscalnum(c)) {
+			NOTE(REG_UBSALNUM);
+			NOTE(REG_UUNSPEC);
+		}
+		RETV(PLAIN, c);
+		break;
+	}
+
+	assert(NOTREACHED);
+}
+
+/*
+ - skip - skip white space and comments in expanded form
+ ^ static VOID skip(struct vars *);
+ */
+static VOID
+skip(v)
+struct vars *v;
+{
+	chr *start = v->now;
+
+	assert(v->cflags&REG_EXPANDED);
+
+	for (;;) {
+		while (!ATEOS() && iscspace(*v->now))
+			v->now++;
+		if (ATEOS() || *v->now != CHR('#'))
+			break;				/* NOTE BREAK OUT */
+		assert(NEXT1('#'));
+		while (!ATEOS() && *v->now != CHR('\n'))
+			v->now++;
+		/* leave the newline to be picked up by the iscspace loop */
+	}
+
+	if (v->now != start)
+		NOTE(REG_UNONPOSIX);
+}
+
+/*
+ - newline - return the chr for a newline
+ * This helps confine use of CHR to this source file.
+ ^ static chr newline(NOPARMS);
+ */
+static chr
+newline()
+{
+	return CHR('\n');
+}
+
+/*
+ - chrnamed - return the chr known by a given (chr string) name
+ * The code is a bit clumsy, but this routine gets only such specialized
+ * use that it hardly matters.
+ ^ static chr chrnamed(struct vars *, chr *, chr *, pchr);
+ */
+static chr
+chrnamed(v, startp, endp, lastresort)
+struct vars *v;
+chr *startp;			/* start of name */
+chr *endp;			/* just past end of name */
+pchr lastresort;		/* what to return if name lookup fails */
+{
+	celt c;
+	int errsave;
+	int e;
+	struct cvec *cv;
+
+	errsave = v->err;
+	v->err = 0;
+	c = element(v, startp, endp);
+	e = v->err;
+	v->err = errsave;
+
+	if (e != 0)
+		return (chr)lastresort;
+
+	cv = range(v, c, c, 0);
+	if (cv->nchrs == 0)
+		return (chr)lastresort;
+	return cv->chrs[0];
+}