Merge commit '98acd3f494b28ddd8c345a2bb9311e41e2d56ddd' as 'tcl8.6'

1 files changed, 2225 insertions, 0 deletions

diff --git a/tcl8.6/generic/regcomp.c b/tcl8.6/generic/regcomp.c
new file mode 100644
index 0000000..211cd70
--- /dev/null
+++ b/tcl8.6/generic/regcomp.c
@@ -0,0 +1,2225 @@
+/*
+ * re_*comp and friends - compile REs
+ * This file #includes several others (see the bottom).
+ *
+ * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
+ *
+ * Development of this software was funded, in part, by Cray Research Inc.,
+ * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
+ * Corporation, none of whom are responsible for the results. The author
+ * thanks all of them.
+ *
+ * Redistribution and use in source and binary forms -- with or without
+ * modification -- are permitted for any purpose, provided that
+ * redistributions in source form retain this entire copyright notice and
+ * indicate the origin and nature of any modifications.
+ *
+ * I'd appreciate being given credit for this package in the documentation of
+ * software which uses it, but that is not a requirement.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "regguts.h"
+
+/*
+ * forward declarations, up here so forward datatypes etc. are defined early
+ */
+/* =====^!^===== begin forwards =====^!^===== */
+/* automatically gathered by fwd; do not hand-edit */
+/* === regcomp.c === */
+int compile(regex_t *, const chr *, size_t, int);
+static void moresubs(struct vars *, int);
+static int freev(struct vars *, int);
+static void makesearch(struct vars *, struct nfa *);
+static struct subre *parse(struct vars *, int, int, struct state *, struct state *);
+static struct subre *parsebranch(struct vars *, int, int, struct state *, struct state *, int);
+static void parseqatom(struct vars *, int, int, struct state *, struct state *, struct subre *);
+static void nonword(struct vars *, int, struct state *, struct state *);
+static void word(struct vars *, int, struct state *, struct state *);
+static int scannum(struct vars *);
+static void repeat(struct vars *, struct state *, struct state *, int, int);
+static void bracket(struct vars *, struct state *, struct state *);
+static void cbracket(struct vars *, struct state *, struct state *);
+static void brackpart(struct vars *, struct state *, struct state *);
+static const chr *scanplain(struct vars *);
+static void onechr(struct vars *, pchr, struct state *, struct state *);
+static void dovec(struct vars *, struct cvec *, struct state *, struct state *);
+static void wordchrs(struct vars *);
+static struct subre *subre(struct vars *, int, int, struct state *, struct state *);
+static void freesubre(struct vars *, struct subre *);
+static void freesrnode(struct vars *, struct subre *);
+static void optst(struct vars *, struct subre *);
+static int numst(struct subre *, int);
+static void markst(struct subre *);
+static void cleanst(struct vars *);
+static long nfatree(struct vars *, struct subre *, FILE *);
+static long nfanode(struct vars *, struct subre *, FILE *);
+static int newlacon(struct vars *, struct state *, struct state *, int);
+static void freelacons(struct subre *, int);
+static void rfree(regex_t *);
+static void dump(regex_t *, FILE *);
+static void dumpst(struct subre *, FILE *, int);
+static void stdump(struct subre *, FILE *, int);
+static const char *stid(struct subre *, char *, size_t);
+/* === regc_lex.c === */
+static void lexstart(struct vars *);
+static void prefixes(struct vars *);
+static void lexnest(struct vars *, const chr *, const chr *);
+static void lexword(struct vars *);
+static int next(struct vars *);
+static int lexescape(struct vars *);
+static int lexdigits(struct vars *, int, int, int);
+static int brenext(struct vars *, pchr);
+static void skip(struct vars *);
+static chr newline(NOPARMS);
+static chr chrnamed(struct vars *, const chr *, const chr *, pchr);
+/* === regc_color.c === */
+static void initcm(struct vars *, struct colormap *);
+static void freecm(struct colormap *);
+static void cmtreefree(struct colormap *, union tree *, int);
+static color setcolor(struct colormap *, pchr, pcolor);
+static color maxcolor(struct colormap *);
+static color newcolor(struct colormap *);
+static void freecolor(struct colormap *, pcolor);
+static color pseudocolor(struct colormap *);
+static color subcolor(struct colormap *, pchr c);
+static color newsub(struct colormap *, pcolor);
+static void subrange(struct vars *, pchr, pchr, struct state *, struct state *);
+static void subblock(struct vars *, pchr, struct state *, struct state *);
+static void okcolors(struct nfa *, struct colormap *);
+static void colorchain(struct colormap *, struct arc *);
+static void uncolorchain(struct colormap *, struct arc *);
+static void rainbow(struct nfa *, struct colormap *, int, pcolor, struct state *, struct state *);
+static void colorcomplement(struct nfa *, struct colormap *, int, struct state *, struct state *, struct state *);
+#ifdef REG_DEBUG
+static void dumpcolors(struct colormap *, FILE *);
+static void fillcheck(struct colormap *, union tree *, int, FILE *);
+static void dumpchr(pchr, FILE *);
+#endif
+/* === regc_nfa.c === */
+static struct nfa *newnfa(struct vars *, struct colormap *, struct nfa *);
+static void freenfa(struct nfa *);
+static struct state *newstate(struct nfa *);
+static struct state *newfstate(struct nfa *, int flag);
+static void dropstate(struct nfa *, struct state *);
+static void freestate(struct nfa *, struct state *);
+static void destroystate(struct nfa *, struct state *);
+static void newarc(struct nfa *, int, pcolor, struct state *, struct state *);
+static void createarc(struct nfa *, int, pcolor, struct state *, struct state *);
+static struct arc *allocarc(struct nfa *, struct state *);
+static void freearc(struct nfa *, struct arc *);
+static void changearctarget(struct arc *, struct state *);
+static int hasnonemptyout(struct state *);
+static struct arc *findarc(struct state *, int, pcolor);
+static void cparc(struct nfa *, struct arc *, struct state *, struct state *);
+static void sortins(struct nfa *, struct state *);
+static int sortins_cmp(const void *, const void *);
+static void sortouts(struct nfa *, struct state *);
+static int sortouts_cmp(const void *, const void *);
+static void moveins(struct nfa *, struct state *, struct state *);
+static void copyins(struct nfa *, struct state *, struct state *);
+static void mergeins(struct nfa *, struct state *, struct arc **, int);
+static void moveouts(struct nfa *, struct state *, struct state *);
+static void copyouts(struct nfa *, struct state *, struct state *);
+static void cloneouts(struct nfa *, struct state *, struct state *, struct state *, int);
+static void delsub(struct nfa *, struct state *, struct state *);
+static void deltraverse(struct nfa *, struct state *, struct state *);
+static void dupnfa(struct nfa *, struct state *, struct state *, struct state *, struct state *);
+static void duptraverse(struct nfa *, struct state *, struct state *, int);
+static void cleartraverse(struct nfa *, struct state *);
+static void specialcolors(struct nfa *);
+static long optimize(struct nfa *, FILE *);
+static void pullback(struct nfa *, FILE *);
+static int pull(struct nfa *, struct arc *, struct state **);
+static void pushfwd(struct nfa *, FILE *);
+static int push(struct nfa *, struct arc *, struct state **);
+#define	INCOMPATIBLE	1	/* destroys arc */
+#define	SATISFIED	2	/* constraint satisfied */
+#define	COMPATIBLE	3	/* compatible but not satisfied yet */
+static int combine(struct arc *, struct arc *);
+static void fixempties(struct nfa *, FILE *);
+static struct state *emptyreachable(struct nfa *, struct state *,
+			struct state *, struct arc **);
+static int	isconstraintarc(struct arc *);
+static int	hasconstraintout(struct state *);
+static void fixconstraintloops(struct nfa *, FILE *);
+static int	findconstraintloop(struct nfa *, struct state *);
+static void breakconstraintloop(struct nfa *, struct state *);
+static void clonesuccessorstates(struct nfa *, struct state *, struct state *,
+		 struct state *, struct arc *, char *, char *, int);
+static void cleanup(struct nfa *);
+static void markreachable(struct nfa *, struct state *, struct state *, struct state *);
+static void markcanreach(struct nfa *, struct state *, struct state *, struct state *);
+static long analyze(struct nfa *);
+static void compact(struct nfa *, struct cnfa *);
+static void carcsort(struct carc *, size_t);
+static int carc_cmp(const void *, const void *);
+static void freecnfa(struct cnfa *);
+static void dumpnfa(struct nfa *, FILE *);
+#ifdef REG_DEBUG
+static void dumpstate(struct state *, FILE *);
+static void dumparcs(struct state *, FILE *);
+static void dumparc(struct arc *, struct state *, FILE *);
+#endif
+static void dumpcnfa(struct cnfa *, FILE *);
+#ifdef REG_DEBUG
+static void dumpcstate(int, struct cnfa *, FILE *);
+#endif
+/* === regc_cvec.c === */
+static struct cvec *clearcvec(struct cvec *);
+static void addchr(struct cvec *, pchr);
+static void addrange(struct cvec *, pchr, pchr);
+static struct cvec *newcvec(int, int);
+static struct cvec *getcvec(struct vars *, int, int);
+static void freecvec(struct cvec *);
+/* === regc_locale.c === */
+static celt element(struct vars *, const chr *, const chr *);
+static struct cvec *range(struct vars *, celt, celt, int);
+static int before(celt, celt);
+static struct cvec *eclass(struct vars *, celt, int);
+static struct cvec *cclass(struct vars *, const chr *, const chr *, int);
+static struct cvec *allcases(struct vars *, pchr);
+static int cmp(const chr *, const chr *, size_t);
+static int casecmp(const chr *, const chr *, size_t);
+/* automatically gathered by fwd; do not hand-edit */
+/* =====^!^===== end forwards =====^!^===== */
+
+/* internal variables, bundled for easy passing around */
+struct vars {
+    regex_t *re;
+    const chr *now;		/* scan pointer into string */
+    const chr *stop;		/* end of string */
+    const chr *savenow;		/* saved now and stop for "subroutine call" */
+    const chr *savestop;
+    int err;			/* error code (0 if none) */
+    int cflags;			/* copy of compile flags */
+    int lasttype;		/* type of previous token */
+    int nexttype;		/* type of next token */
+    chr nextvalue;		/* value (if any) of next token */
+    int lexcon;			/* lexical context type (see lex.c) */
+    int nsubexp;		/* subexpression count */
+    struct subre **subs;	/* subRE pointer vector */
+    size_t nsubs;		/* length of vector */
+    struct subre *sub10[10];	/* initial vector, enough for most */
+    struct nfa *nfa;		/* the NFA */
+    struct colormap *cm;	/* character color map */
+    color nlcolor;		/* color of newline */
+    struct state *wordchrs;	/* state in nfa holding word-char outarcs */
+    struct subre *tree;		/* subexpression tree */
+    struct subre *treechain;	/* all tree nodes allocated */
+    struct subre *treefree;	/* any free tree nodes */
+    int ntree;			/* number of tree nodes, plus one */
+    struct cvec *cv;		/* interface cvec */
+    struct cvec *cv2;		/* utility cvec */
+    struct subre *lacons;	/* lookahead-constraint vector */
+    int nlacons;		/* size of lacons */
+    size_t spaceused;		/* approx. space used for compilation */
+};
+
+/* parsing macros; most know that `v' is the struct vars pointer */
+#define	NEXT()	(next(v))		/* advance by one token */
+#define	SEE(t)	(v->nexttype == (t))	/* is next token this? */
+#define	EAT(t)	(SEE(t) && next(v))	/* if next is this, swallow it */
+#define	VISERR(vv)	((vv)->err != 0)/* have we seen an error yet? */
+#define	ISERR()	VISERR(v)
+#define VERR(vv,e)	((vv)->nexttype = EOS, \
+			 (vv)->err = ((vv)->err ? (vv)->err : (e)))
+#define	ERR(e)	VERR(v, e)		/* record an error */
+#define	NOERR()	{if (ISERR()) return;}	/* if error seen, return */
+#define	NOERRN()	{if (ISERR()) return NULL;}	/* NOERR with retval */
+#define	NOERRZ()	{if (ISERR()) return 0;}	/* NOERR with retval */
+#define INSIST(c, e) do { if (!(c)) ERR(e); } while (0)	/* error if c false */
+#define	NOTE(b)	(v->re->re_info |= (b))		/* note visible condition */
+#define	EMPTYARC(x, y)	newarc(v->nfa, EMPTY, 0, x, y)
+
+/* token type codes, some also used as NFA arc types */
+#define	EMPTY	'n'		/* no token present */
+#define	EOS	'e'		/* end of string */
+#define	PLAIN	'p'		/* ordinary character */
+#define	DIGIT	'd'		/* digit (in bound) */
+#define	BACKREF	'b'		/* back reference */
+#define	COLLEL	'I'		/* start of [. */
+#define	ECLASS	'E'		/* start of [= */
+#define	CCLASS	'C'		/* start of [: */
+#define	END	'X'		/* end of [. [= [: */
+#define	RANGE	'R'		/* - within [] which might be range delim. */
+#define	LACON	'L'		/* lookahead constraint subRE */
+#define	AHEAD	'a'		/* color-lookahead arc */
+#define	BEHIND	'r'		/* color-lookbehind arc */
+#define	WBDRY	'w'		/* word boundary constraint */
+#define	NWBDRY	'W'		/* non-word-boundary constraint */
+#define	SBEGIN	'A'		/* beginning of string (even if not BOL) */
+#define	SEND	'Z'		/* end of string (even if not EOL) */
+#define	PREFER	'P'		/* length preference */
+
+/* is an arc colored, and hence on a color chain? */
+#define	COLORED(a) \
+	((a)->type == PLAIN || (a)->type == AHEAD || (a)->type == BEHIND)
+
+/* static function list */
+static const struct fns functions = {
+    rfree,			/* regfree insides */
+};
+
+/*
+ - compile - compile regular expression
+ * Note: on failure, no resources remain allocated, so regfree()
+ * need not be applied to re.
+ ^ int compile(regex_t *, const chr *, size_t, int);
+ */
+int
+compile(
+    regex_t *re,
+    const chr *string,
+    size_t len,
+    int flags)
+{
+    AllocVars(v);
+    struct guts *g;
+    int i;
+    size_t j;
+    FILE *debug = (flags&REG_PROGRESS) ? stdout : NULL;
+#define	CNOERR()	{ if (ISERR()) return freev(v, v->err); }
+
+    /*
+     * Sanity checks.
+     */
+
+    if (re == NULL || string == NULL) {
+	FreeVars(v);
+	return REG_INVARG;
+    }
+    if ((flags&REG_QUOTE) && (flags&(REG_ADVANCED|REG_EXPANDED|REG_NEWLINE))) {
+	FreeVars(v);
+	return REG_INVARG;
+    }
+    if (!(flags&REG_EXTENDED) && (flags&REG_ADVF)) {
+	FreeVars(v);
+	return REG_INVARG;
+    }
+
+    /*
+     * Initial setup (after which freev() is callable).
+     */
+
+    v->re = re;
+    v->now = string;
+    v->stop = v->now + len;
+    v->savenow = v->savestop = NULL;
+    v->err = 0;
+    v->cflags = flags;
+    v->nsubexp = 0;
+    v->subs = v->sub10;
+    v->nsubs = 10;
+    for (j = 0; j < v->nsubs; j++) {
+	v->subs[j] = NULL;
+    }
+    v->nfa = NULL;
+    v->cm = NULL;
+    v->nlcolor = COLORLESS;
+    v->wordchrs = NULL;
+    v->tree = NULL;
+    v->treechain = NULL;
+    v->treefree = NULL;
+    v->cv = NULL;
+    v->cv2 = NULL;
+    v->lacons = NULL;
+    v->nlacons = 0;
+    v->spaceused = 0;
+    re->re_magic = REMAGIC;
+    re->re_info = 0;		/* bits get set during parse */
+    re->re_csize = sizeof(chr);
+    re->re_guts = NULL;
+    re->re_fns = VS(&functions);
+
+    /*
+     * More complex setup, malloced things.
+     */
+
+    re->re_guts = VS(MALLOC(sizeof(struct guts)));
+    if (re->re_guts == NULL) {
+	return freev(v, REG_ESPACE);
+    }
+    g = (struct guts *) re->re_guts;
+    g->tree = NULL;
+    initcm(v, &g->cmap);
+    v->cm = &g->cmap;
+    g->lacons = NULL;
+    g->nlacons = 0;
+    ZAPCNFA(g->search);
+    v->nfa = newnfa(v, v->cm, NULL);
+    CNOERR();
+    v->cv = newcvec(100, 20);
+    if (v->cv == NULL) {
+	return freev(v, REG_ESPACE);
+    }
+
+    /*
+     * Parsing.
+     */
+
+    lexstart(v);		/* also handles prefixes */
+    if ((v->cflags&REG_NLSTOP) || (v->cflags&REG_NLANCH)) {
+	/*
+	 * Assign newline a unique color.
+	 */
+
+	v->nlcolor = subcolor(v->cm, newline());
+	okcolors(v->nfa, v->cm);
+    }
+    CNOERR();
+    v->tree = parse(v, EOS, PLAIN, v->nfa->init, v->nfa->final);
+    assert(SEE(EOS));		/* even if error; ISERR() => SEE(EOS) */
+    CNOERR();
+    assert(v->tree != NULL);
+
+    /*
+     * Finish setup of nfa and its subre tree.
+     */
+
+    specialcolors(v->nfa);
+    CNOERR();
+    if (debug != NULL) {
+	fprintf(debug, "\n\n\n========= RAW ==========\n");
+	dumpnfa(v->nfa, debug);
+	dumpst(v->tree, debug, 1);
+    }
+    optst(v, v->tree);
+    v->ntree = numst(v->tree, 1);
+    markst(v->tree);
+    cleanst(v);
+    if (debug != NULL) {
+	fprintf(debug, "\n\n\n========= TREE FIXED ==========\n");
+	dumpst(v->tree, debug, 1);
+    }
+
+    /*
+     * Build compacted NFAs for tree and lacons.
+     */
+
+    re->re_info |= nfatree(v, v->tree, debug);
+    CNOERR();
+    assert(v->nlacons == 0 || v->lacons != NULL);
+    for (i = 1; i < v->nlacons; i++) {
+	if (debug != NULL) {
+	    fprintf(debug, "\n\n\n========= LA%d ==========\n", i);
+	}
+	nfanode(v, &v->lacons[i], debug);
+    }
+    CNOERR();
+    if (v->tree->flags&SHORTER) {
+	NOTE(REG_USHORTEST);
+    }
+
+    /*
+     * Build compacted NFAs for tree, lacons, fast search.
+     */
+
+    if (debug != NULL) {
+	fprintf(debug, "\n\n\n========= SEARCH ==========\n");
+    }
+
+    /*
+     * Can sacrifice main NFA now, so use it as work area.
+     */
+
+    (DISCARD) optimize(v->nfa, debug);
+    CNOERR();
+    makesearch(v, v->nfa);
+    CNOERR();
+    compact(v->nfa, &g->search);
+    CNOERR();
+
+    /*
+     * Looks okay, package it up.
+     */
+
+    re->re_nsub = v->nsubexp;
+    v->re = NULL;		/* freev no longer frees re */
+    g->magic = GUTSMAGIC;
+    g->cflags = v->cflags;
+    g->info = re->re_info;
+    g->nsub = re->re_nsub;
+    g->tree = v->tree;
+    v->tree = NULL;
+    g->ntree = v->ntree;
+    g->compare = (v->cflags&REG_ICASE) ? casecmp : cmp;
+    g->lacons = v->lacons;
+    v->lacons = NULL;
+    g->nlacons = v->nlacons;
+
+    if (flags&REG_DUMP) {
+	dump(re, stdout);
+    }
+
+    assert(v->err == 0);
+    return freev(v, 0);
+}
+
+/*
+ - moresubs - enlarge subRE vector
+ ^ static void moresubs(struct vars *, int);
+ */
+static void
+moresubs(
+    struct vars *v,
+    int wanted)			/* want enough room for this one */
+{
+    struct subre **p;
+    size_t n;
+
+    assert(wanted > 0 && (size_t)wanted >= v->nsubs);
+    n = (size_t)wanted * 3 / 2 + 1;
+    if (v->subs == v->sub10) {
+	p = (struct subre **) MALLOC(n * sizeof(struct subre *));
+	if (p != NULL) {
+	    memcpy(p, v->subs, v->nsubs * sizeof(struct subre *));
+	}
+    } else {
+	p = (struct subre **) REALLOC(v->subs, n*sizeof(struct subre *));
+    }
+    if (p == NULL) {
+	ERR(REG_ESPACE);
+	return;
+    }
+
+    v->subs = p;
+    for (p = &v->subs[v->nsubs]; v->nsubs < n; p++, v->nsubs++) {
+	*p = NULL;
+    }
+    assert(v->nsubs == n);
+    assert((size_t)wanted < v->nsubs);
+}
+
+/*
+ - freev - free vars struct's substructures where necessary
+ * Optionally does error-number setting, and always returns error code (if
+ * any), to make error-handling code terser.
+ ^ static int freev(struct vars *, int);
+ */
+static int
+freev(
+    struct vars *v,
+    int err)
+{
+    register int ret;
+
+    if (v->re != NULL) {
+	rfree(v->re);
+    }
+    if (v->subs != v->sub10) {
+	FREE(v->subs);
+    }
+    if (v->nfa != NULL) {
+	freenfa(v->nfa);
+    }
+    if (v->tree != NULL) {
+	freesubre(v, v->tree);
+    }
+    if (v->treechain != NULL) {
+	cleanst(v);
+    }
+    if (v->cv != NULL) {
+	freecvec(v->cv);
+    }
+    if (v->cv2 != NULL) {
+	freecvec(v->cv2);
+    }
+    if (v->lacons != NULL) {
+	freelacons(v->lacons, v->nlacons);
+    }
+    ERR(err);			/* nop if err==0 */
+
+    ret = v->err;
+    FreeVars(v);
+    return ret;
+}
+
+/*
+ - makesearch - turn an NFA into a search NFA (implicit prepend of .*?)
+ * NFA must have been optimize()d already.
+ ^ static void makesearch(struct vars *, struct nfa *);
+ */
+static void
+makesearch(
+    struct vars *v,
+    struct nfa *nfa)
+{
+    struct arc *a, *b;
+    struct state *pre = nfa->pre;
+    struct state *s, *s2, *slist;
+
+    /*
+     * No loops are needed if it's anchored.
+     */
+
+    for (a = pre->outs; a != NULL; a = a->outchain) {
+	assert(a->type == PLAIN);
+	if (a->co != nfa->bos[0] && a->co != nfa->bos[1]) {
+	    break;
+	}
+    }
+    if (a != NULL) {
+	/*
+	 * Add implicit .* in front.
+	 */
+
+	rainbow(nfa, v->cm, PLAIN, COLORLESS, pre, pre);
+
+	/*
+	 * And ^* and \A* too -- not always necessary, but harmless.
+	 */
+
+	newarc(nfa, PLAIN, nfa->bos[0], pre, pre);
+	newarc(nfa, PLAIN, nfa->bos[1], pre, pre);
+    }
+
+    /*
+     * Now here's the subtle part. Because many REs have no lookback
+     * constraints, often knowing when you were in the pre state tells you
+     * little; it's the next state(s) that are informative. But some of them
+     * may have other inarcs, i.e. it may be possible to make actual progress
+     * and then return to one of them. We must de-optimize such cases,
+     * splitting each such state into progress and no-progress states.
+     */
+
+    /*
+     * First, make a list of the states.
+     */
+
+    slist = NULL;
+    for (a=pre->outs ; a!=NULL ; a=a->outchain) {
+	s = a->to;
+	for (b=s->ins ; b!=NULL ; b=b->inchain) {
+	    if (b->from != pre) {
+		break;
+	    }
+	}
+
+	/*
+	 * We want to mark states as being in the list already by having non
+	 * NULL tmp fields, but we can't just store the old slist value in tmp
+	 * because that doesn't work for the first such state.  Instead, the
+	 * first list entry gets its own address in tmp.
+	 */
+	if (b != NULL && s->tmp == NULL) {
+	    s->tmp = (slist != NULL) ? slist : s;
+	    slist = s;
+	}
+    }
+
+    /*
+     * Do the splits.
+     */
+
+    for (s=slist ; s!=NULL ; s=s2) {
+	s2 = newstate(nfa);
+	NOERR();
+	copyouts(nfa, s, s2);
+	NOERR();
+	for (a=s->ins ; a!=NULL ; a=b) {
+	    b = a->inchain;
+
+	    if (a->from != pre) {
+		cparc(nfa, a, a->from, s2);
+		freearc(nfa, a);
+	    }
+	}
+	s2 = (s->tmp != s) ? s->tmp : NULL;
+	s->tmp = NULL;		/* clean up while we're at it */
+    }
+}
+
+/*
+ - parse - parse an RE
+ * This is actually just the top level, which parses a bunch of branches tied
+ * together with '|'. They appear in the tree as the left children of a chain
+ * of '|' subres.
+ ^ static struct subre *parse(struct vars *, int, int, struct state *,
+ ^ 	struct state *);
+ */
+static struct subre *
+parse(
+    struct vars *v,
+    int stopper,		/* EOS or ')' */
+    int type,			/* LACON (lookahead subRE) or PLAIN */
+    struct state *init,		/* initial state */
+    struct state *final)	/* final state */
+{
+    struct state *left, *right;	/* scaffolding for branch */
+    struct subre *branches;	/* top level */
+    struct subre *branch;	/* current branch */
+    struct subre *t;		/* temporary */
+    int firstbranch;		/* is this the first branch? */
+
+    assert(stopper == ')' || stopper == EOS);
+
+    branches = subre(v, '|', LONGER, init, final);
+    NOERRN();
+    branch = branches;
+    firstbranch = 1;
+    do {	/* a branch */
+	if (!firstbranch) {
+	    /*
+	     * Need a place to hang the branch.
+	     */
+
+	    branch->right = subre(v, '|', LONGER, init, final);
+	    NOERRN();
+	    branch = branch->right;
+	}
+	firstbranch = 0;
+	left = newstate(v->nfa);
+	right = newstate(v->nfa);
+	NOERRN();
+	EMPTYARC(init, left);
+	EMPTYARC(right, final);
+	NOERRN();
+	branch->left = parsebranch(v, stopper, type, left, right, 0);
+	NOERRN();
+	branch->flags |= UP(branch->flags | branch->left->flags);
+	if ((branch->flags &~ branches->flags) != 0) {	/* new flags */
+	    for (t = branches; t != branch; t = t->right) {
+		t->flags |= branch->flags;
+	    }
+	}
+    } while (EAT('|'));
+    assert(SEE(stopper) || SEE(EOS));
+
+    if (!SEE(stopper)) {
+	assert(stopper == ')' && SEE(EOS));
+	ERR(REG_EPAREN);
+    }
+
+    /*
+     * Optimize out simple cases.
+     */
+
+    if (branch == branches) {	/* only one branch */
+	assert(branch->right == NULL);
+	t = branch->left;
+	branch->left = NULL;
+	freesubre(v, branches);
+	branches = t;
+    } else if (!MESSY(branches->flags)) {	/* no interesting innards */
+	freesubre(v, branches->left);
+	branches->left = NULL;
+	freesubre(v, branches->right);
+	branches->right = NULL;
+	branches->op = '=';
+    }
+
+    return branches;
+}
+
+/*
+ - parsebranch - parse one branch of an RE
+ * This mostly manages concatenation, working closely with parseqatom().
+ * Concatenated things are bundled up as much as possible, with separate
+ * ',' nodes introduced only when necessary due to substructure.
+ ^ static struct subre *parsebranch(struct vars *, int, int, struct state *,
+ ^ 	struct state *, int);
+ */
+static struct subre *
+parsebranch(
+    struct vars *v,
+    int stopper,		/* EOS or ')' */
+    int type,			/* LACON (lookahead subRE) or PLAIN */
+    struct state *left,		/* leftmost state */
+    struct state *right,	/* rightmost state */
+    int partial)		/* is this only part of a branch? */
+{
+    struct state *lp;		/* left end of current construct */
+    int seencontent;		/* is there anything in this branch yet? */
+    struct subre *t;
+
+    lp = left;
+    seencontent = 0;
+    t = subre(v, '=', 0, left, right);	/* op '=' is tentative */
+    NOERRN();
+    while (!SEE('|') && !SEE(stopper) && !SEE(EOS)) {
+	if (seencontent) {	/* implicit concat operator */
+	    lp = newstate(v->nfa);
+	    NOERRN();
+	    moveins(v->nfa, right, lp);
+	}
+	seencontent = 1;
+
+	/* NB, recursion in parseqatom() may swallow rest of branch */
+	parseqatom(v, stopper, type, lp, right, t);
+	NOERRN();
+    }
+
+    if (!seencontent) {		/* empty branch */
+	if (!partial) {
+	    NOTE(REG_UUNSPEC);
+	}
+	assert(lp == left);
+	EMPTYARC(left, right);
+    }
+
+    return t;
+}
+
+/*
+ - parseqatom - parse one quantified atom or constraint of an RE
+ * The bookkeeping near the end cooperates very closely with parsebranch(); in
+ * particular, it contains a recursion that can involve parsing the rest of
+ * the branch, making this function's name somewhat inaccurate.
+ ^ static void parseqatom(struct vars *, int, int, struct state *,
+ ^ 	struct state *, struct subre *);
+ */
+static void
+parseqatom(
+    struct vars *v,
+    int stopper,		/* EOS or ')' */
+    int type,			/* LACON (lookahead subRE) or PLAIN */
+    struct state *lp,		/* left state to hang it on */
+    struct state *rp,		/* right state to hang it on */
+    struct subre *top)		/* subtree top */
+{
+    struct state *s;		/* temporaries for new states */
+    struct state *s2;
+#define	ARCV(t, val)	newarc(v->nfa, t, val, lp, rp)
+    int m, n;
+    struct subre *atom;		/* atom's subtree */
+    struct subre *t;
+    int cap;			/* capturing parens? */
+    int pos;			/* positive lookahead? */
+    int subno;			/* capturing-parens or backref number */
+    int atomtype;
+    int qprefer;		/* quantifier short/long preference */
+    int f;
+    struct subre **atomp;	/* where the pointer to atom is */
+
+    /*
+     * Initial bookkeeping.
+     */
+
+    atom = NULL;
+    assert(lp->nouts == 0);	/* must string new code */
+    assert(rp->nins == 0);	/* between lp and rp */
+    subno = 0;			/* just to shut lint up */
+
+    /*
+     * An atom or constraint...
+     */
+
+    atomtype = v->nexttype;
+    switch (atomtype) {
+	/* first, constraints, which end by returning */
+    case '^':
+	ARCV('^', 1);
+	if (v->cflags&REG_NLANCH) {
+	    ARCV(BEHIND, v->nlcolor);
+	}
+	NEXT();
+	return;
+    case '$':
+	ARCV('$', 1);
+	if (v->cflags&REG_NLANCH) {
+	    ARCV(AHEAD, v->nlcolor);
+	}
+	NEXT();
+	return;
+    case SBEGIN:
+	ARCV('^', 1);		/* BOL */
+	ARCV('^', 0);		/* or BOS */
+	NEXT();
+	return;
+    case SEND:
+	ARCV('$', 1);		/* EOL */
+	ARCV('$', 0);		/* or EOS */
+	NEXT();
+	return;
+    case '<':
+	wordchrs(v);		/* does NEXT() */
+	s = newstate(v->nfa);
+	NOERR();
+	nonword(v, BEHIND, lp, s);
+	word(v, AHEAD, s, rp);
+	return;
+    case '>':
+	wordchrs(v);		/* does NEXT() */
+	s = newstate(v->nfa);
+	NOERR();
+	word(v, BEHIND, lp, s);
+	nonword(v, AHEAD, s, rp);
+	return;
+    case WBDRY:
+	wordchrs(v);		/* does NEXT() */
+	s = newstate(v->nfa);
+	NOERR();
+	nonword(v, BEHIND, lp, s);
+	word(v, AHEAD, s, rp);
+	s = newstate(v->nfa);
+	NOERR();
+	word(v, BEHIND, lp, s);
+	nonword(v, AHEAD, s, rp);
+	return;
+    case NWBDRY:
+	wordchrs(v);		/* does NEXT() */
+	s = newstate(v->nfa);
+	NOERR();
+	word(v, BEHIND, lp, s);
+	word(v, AHEAD, s, rp);
+	s = newstate(v->nfa);
+	NOERR();
+	nonword(v, BEHIND, lp, s);
+	nonword(v, AHEAD, s, rp);
+	return;
+    case LACON:			/* lookahead constraint */
+	pos = v->nextvalue;
+	NEXT();
+	s = newstate(v->nfa);
+	s2 = newstate(v->nfa);
+	NOERR();
+	t = parse(v, ')', LACON, s, s2);
+	freesubre(v, t);	/* internal structure irrelevant */
+	assert(SEE(')') || ISERR());
+	NEXT();
+	n = newlacon(v, s, s2, pos);
+	NOERR();
+	ARCV(LACON, n);
+	return;
+
+	/*
+	 * Then errors, to get them out of the way.
+	 */
+
+    case '*':
+    case '+':
+    case '?':
+    case '{':
+	ERR(REG_BADRPT);
+	return;
+    default:
+	ERR(REG_ASSERT);
+	return;
+
+	/*
+	 * Then plain characters, and minor variants on that theme.
+	 */
+
+    case ')':			/* unbalanced paren */
+	if ((v->cflags&REG_ADVANCED) != REG_EXTENDED) {
+	    ERR(REG_EPAREN);
+	    return;
+	}
+
+	/*
+	 * Legal in EREs due to specification botch.
+	 */
+
+	NOTE(REG_UPBOTCH);
+	/* fallthrough into case PLAIN */
+    case PLAIN:
+	onechr(v, v->nextvalue, lp, rp);
+	okcolors(v->nfa, v->cm);
+	NOERR();
+	NEXT();
+	break;
+    case '[':
+	if (v->nextvalue == 1) {
+	    bracket(v, lp, rp);
+	} else {
+	    cbracket(v, lp, rp);
+	}
+	assert(SEE(']') || ISERR());
+	NEXT();
+	break;
+    case '.':
+	rainbow(v->nfa, v->cm, PLAIN,
+		(v->cflags&REG_NLSTOP) ? v->nlcolor : COLORLESS, lp, rp);
+	NEXT();
+	break;
+
+	/*
+	 * And finally the ugly stuff.
+	 */
+
+    case '(':			/* value flags as capturing or non */
+	cap = (type == LACON) ? 0 : v->nextvalue;
+	if (cap) {
+	    v->nsubexp++;
+	    subno = v->nsubexp;
+	    if ((size_t)subno >= v->nsubs) {
+		moresubs(v, subno);
+	    }
+	    assert((size_t)subno < v->nsubs);
+	} else {
+	    atomtype = PLAIN;	/* something that's not '(' */
+	}
+	NEXT();
+
+	/*
+	 * Need new endpoints because tree will contain pointers.
+	 */
+
+	s = newstate(v->nfa);
+	s2 = newstate(v->nfa);
+	NOERR();
+	EMPTYARC(lp, s);
+	EMPTYARC(s2, rp);
+	NOERR();
+	atom = parse(v, ')', PLAIN, s, s2);
+	assert(SEE(')') || ISERR());
+	NEXT();
+	NOERR();
+	if (cap) {
+	    v->subs[subno] = atom;
+	    t = subre(v, '(', atom->flags|CAP, lp, rp);
+	    NOERR();
+	    t->subno = subno;
+	    t->left = atom;
+	    atom = t;
+	}
+
+	/*
+	 * Postpone everything else pending possible {0}.
+	 */
+
+	break;
+    case BACKREF:		/* the Feature From The Black Lagoon */
+	INSIST(type != LACON, REG_ESUBREG);
+	INSIST(v->nextvalue < v->nsubs, REG_ESUBREG);
+	INSIST(v->subs[v->nextvalue] != NULL, REG_ESUBREG);
+	NOERR();
+	assert(v->nextvalue > 0);
+	atom = subre(v, 'b', BACKR, lp, rp);
+	NOERR();
+	subno = v->nextvalue;
+	atom->subno = subno;
+	EMPTYARC(lp, rp);	/* temporarily, so there's something */
+	NEXT();
+	break;
+    }
+
+    /*
+     * ...and an atom may be followed by a quantifier.
+     */
+
+    switch (v->nexttype) {
+    case '*':
+	m = 0;
+	n = DUPINF;
+	qprefer = (v->nextvalue) ? LONGER : SHORTER;
+	NEXT();
+	break;
+    case '+':
+	m = 1;
+	n = DUPINF;
+	qprefer = (v->nextvalue) ? LONGER : SHORTER;
+	NEXT();
+	break;
+    case '?':
+	m = 0;
+	n = 1;
+	qprefer = (v->nextvalue) ? LONGER : SHORTER;
+	NEXT();
+	break;
+    case '{':
+	NEXT();
+	m = scannum(v);
+	if (EAT(',')) {
+	    if (SEE(DIGIT)) {
+		n = scannum(v);
+	    } else {
+		n = DUPINF;
+	    }
+	    if (m > n) {
+		ERR(REG_BADBR);
+		return;
+	    }
+
+	    /*
+	     * {m,n} exercises preference, even if it's {m,m}
+	     */
+
+	    qprefer = (v->nextvalue) ? LONGER : SHORTER;
+	} else {
+	    n = m;
+	    /*
+	     * {m} passes operand's preference through.
+	     */
+
+	    qprefer = 0;
+	}
+	if (!SEE('}')) {	/* catches errors too */
+	    ERR(REG_BADBR);
+	    return;
+	}
+	NEXT();
+	break;
+    default:			/* no quantifier */
+	m = n = 1;
+	qprefer = 0;
+	break;
+    }
+
+    /*
+     * Annoying special case: {0} or {0,0} cancels everything.
+     */
+
+    if (m == 0 && n == 0) {
+	if (atom != NULL) {
+	    freesubre(v, atom);
+	}
+	if (atomtype == '(') {
+	    v->subs[subno] = NULL;
+	}
+	delsub(v->nfa, lp, rp);
+	EMPTYARC(lp, rp);
+	return;
+    }
+
+    /*
+     * If not a messy case, avoid hard part.
+     */
+
+    assert(!MESSY(top->flags));
+    f = top->flags | qprefer | ((atom != NULL) ? atom->flags : 0);
+    if (atomtype != '(' && atomtype != BACKREF && !MESSY(UP(f))) {
+	if (!(m == 1 && n == 1)) {
+	    repeat(v, lp, rp, m, n);
+	}
+	if (atom != NULL) {
+	    freesubre(v, atom);
+	}
+	top->flags = f;
+	return;
+    }
+
+    /*
+     * hard part: something messy
+     * That is, capturing parens, back reference, short/long clash, or an atom
+     * with substructure containing one of those.
+     */
+
+    /*
+     * Now we'll need a subre for the contents even if they're boring.
+     */
+
+    if (atom == NULL) {
+	atom = subre(v, '=', 0, lp, rp);
+	NOERR();
+    }
+
+    /*
+     * Prepare a general-purpose state skeleton.
+     *
+     * In the no-backrefs case, we want this:
+     *
+     * [lp] ---> [s] ---prefix---> [begin] ---atom---> [end] ---rest---> [rp]
+     *
+     * where prefix is some repetitions of atom.  In the general case we need
+     *
+     * [lp] ---> [s] ---iterator---> [s2] ---rest---> [rp]
+     *
+     * where the iterator wraps around [begin] ---atom---> [end]
+     *
+     * We make the s state here for both cases; s2 is made below if needed
+     */
+
+    s = newstate(v->nfa);	/* first, new endpoints for the atom */
+    s2 = newstate(v->nfa);
+    NOERR();
+    moveouts(v->nfa, lp, s);
+    moveins(v->nfa, rp, s2);
+    NOERR();
+    atom->begin = s;
+    atom->end = s2;
+    s = newstate(v->nfa);	/* set up starting state */
+    NOERR();
+    EMPTYARC(lp, s);
+    NOERR();
+
+    /*
+     * Break remaining subRE into x{...} and what follows.
+     */
+
+    t = subre(v, '.', COMBINE(qprefer, atom->flags), lp, rp);
+    NOERR();
+    t->left = atom;
+    atomp = &t->left;
+
+    /*
+     * Here we should recurse... but we must postpone that to the end.
+     */
+
+    /*
+     * Split top into prefix and remaining.
+     */
+
+    assert(top->op == '=' && top->left == NULL && top->right == NULL);
+    top->left = subre(v, '=', top->flags, top->begin, lp);
+    NOERR();
+    top->op = '.';
+    top->right = t;
+
+    /*
+     * If it's a backref, now is the time to replicate the subNFA.
+     */
+
+    if (atomtype == BACKREF) {
+	assert(atom->begin->nouts == 1);	/* just the EMPTY */
+	delsub(v->nfa, atom->begin, atom->end);
+	assert(v->subs[subno] != NULL);
+
+	/*
+	 * And here's why the recursion got postponed: it must wait until the
+	 * skeleton is filled in, because it may hit a backref that wants to
+	 * copy the filled-in skeleton.
+	 */
+
+	dupnfa(v->nfa, v->subs[subno]->begin, v->subs[subno]->end,
+		atom->begin, atom->end);
+	NOERR();
+    }
+
+    /*
+     * It's quantifier time.  If the atom is just a backref, we'll let it deal
+     * with quantifiers internally.
+     */
+
+    if (atomtype == BACKREF) {
+	/*
+	 * Special case: backrefs have internal quantifiers.
+	 */
+
+	EMPTYARC(s, atom->begin);	/* empty prefix */
+
+	/*
+	 * Just stuff everything into atom.
+	 */
+
+	repeat(v, atom->begin, atom->end, m, n);
+	atom->min = (short) m;
+	atom->max = (short) n;
+	atom->flags |= COMBINE(qprefer, atom->flags);
+	/* rest of branch can be strung starting from atom->end */
+	s2 = atom->end;
+    } else if (m == 1 && n == 1) {
+	/*
+	 * No/vacuous quantifier: done.
+	 */
+
+	EMPTYARC(s, atom->begin);	/* empty prefix */
+	/* rest of branch can be strung starting from atom->end */
+	s2 = atom->end;
+    } else if (m > 0 && !(atom->flags & BACKR)) {
+	/*
+	 * If there's no backrefs involved, we can turn x{m,n} into
+	 * x{m-1,n-1}x, with capturing parens in only the second x.  This
+	 * is valid because we only care about capturing matches from the
+	 * final iteration of the quantifier.  It's a win because we can
+	 * implement the backref-free left side as a plain DFA node, since
+	 * we don't really care where its submatches are.
+	 */
+
+	dupnfa(v->nfa, atom->begin, atom->end, s, atom->begin);
+	assert(m >= 1 && m != DUPINF && n >= 1);
+	repeat(v, s, atom->begin, m-1, (n == DUPINF) ? n : n-1);
+	f = COMBINE(qprefer, atom->flags);
+	t = subre(v, '.', f, s, atom->end);	/* prefix and atom */
+	NOERR();
+	t->left = subre(v, '=', PREF(f), s, atom->begin);
+	NOERR();
+	t->right = atom;
+	*atomp = t;
+	/* rest of branch can be strung starting from atom->end */
+	s2 = atom->end;
+    } else {
+	/* general case: need an iteration node */
+	s2 = newstate(v->nfa);
+	NOERR();
+	moveouts(v->nfa, atom->end, s2);
+	NOERR();
+	dupnfa(v->nfa, atom->begin, atom->end, s, s2);
+	repeat(v, s, s2, m, n);
+	f = COMBINE(qprefer, atom->flags);
+	t = subre(v, '*', f, s, s2);
+	NOERR();
+	t->min = (short) m;
+	t->max = (short) n;
+	t->left = atom;
+	*atomp = t;
+	/* rest of branch is to be strung from iteration's end state */
+    }
+
+    /*
+     * And finally, look after that postponed recursion.
+     */
+
+    t = top->right;
+    if (!(SEE('|') || SEE(stopper) || SEE(EOS))) {
+	t->right = parsebranch(v, stopper, type, s2, rp, 1);
+    } else {
+	EMPTYARC(s2, rp);
+	t->right = subre(v, '=', 0, s2, rp);
+    }
+    NOERR();
+    assert(SEE('|') || SEE(stopper) || SEE(EOS));
+    t->flags |= COMBINE(t->flags, t->right->flags);
+    top->flags |= COMBINE(top->flags, t->flags);
+}
+
+/*
+ - nonword - generate arcs for non-word-character ahead or behind
+ ^ static void nonword(struct vars *, int, struct state *, struct state *);
+ */
+static void
+nonword(
+    struct vars *v,
+    int dir,			/* AHEAD or BEHIND */
+    struct state *lp,
+    struct state *rp)
+{
+    int anchor = (dir == AHEAD) ? '$' : '^';
+
+    assert(dir == AHEAD || dir == BEHIND);
+    newarc(v->nfa, anchor, 1, lp, rp);
+    newarc(v->nfa, anchor, 0, lp, rp);
+    colorcomplement(v->nfa, v->cm, dir, v->wordchrs, lp, rp);
+    /* (no need for special attention to \n) */
+}
+
+/*
+ - word - generate arcs for word character ahead or behind
+ ^ static void word(struct vars *, int, struct state *, struct state *);
+ */
+static void
+word(
+    struct vars *v,
+    int dir,			/* AHEAD or BEHIND */
+    struct state *lp,
+    struct state *rp)
+{
+    assert(dir == AHEAD || dir == BEHIND);
+    cloneouts(v->nfa, v->wordchrs, lp, rp, dir);
+    /* (no need for special attention to \n) */
+}
+
+/*
+ - scannum - scan a number
+ ^ static int scannum(struct vars *);
+ */
+static int			/* value, <= DUPMAX */
+scannum(
+    struct vars *v)
+{
+    int n = 0;
+
+    while (SEE(DIGIT) && n < DUPMAX) {
+	n = n*10 + v->nextvalue;
+	NEXT();
+    }
+    if (SEE(DIGIT) || n > DUPMAX) {
+	ERR(REG_BADBR);
+	return 0;
+    }
+    return n;
+}
+
+/*
+ - repeat - replicate subNFA for quantifiers
+ * The sub-NFA strung from lp to rp is modified to represent m to n
+ * repetitions of its initial contents.
+ * The duplication sequences used here are chosen carefully so that any
+ * pointers starting out pointing into the subexpression end up pointing into
+ * the last occurrence. (Note that it may not be strung between the same left
+ * and right end states, however!) This used to be important for the subRE
+ * tree, although the important bits are now handled by the in-line code in
+ * parse(), and when this is called, it doesn't matter any more.
+ ^ static void repeat(struct vars *, struct state *, struct state *, int, int);
+ */
+static void
+repeat(
+    struct vars *v,
+    struct state *lp,
+    struct state *rp,
+    int m,
+    int n)
+{
+#define	SOME		2
+#define	INF		3
+#define	PAIR(x, y)	((x)*4 + (y))
+#define	REDUCE(x)	( ((x) == DUPINF) ? INF : (((x) > 1) ? SOME : (x)) )
+    const int rm = REDUCE(m);
+    const int rn = REDUCE(n);
+    struct state *s, *s2;
+
+    switch (PAIR(rm, rn)) {
+    case PAIR(0, 0):		/* empty string */
+	delsub(v->nfa, lp, rp);
+	EMPTYARC(lp, rp);
+	break;
+    case PAIR(0, 1):		/* do as x| */
+	EMPTYARC(lp, rp);
+	break;
+    case PAIR(0, SOME):		/* do as x{1,n}| */
+	repeat(v, lp, rp, 1, n);
+	NOERR();
+	EMPTYARC(lp, rp);
+	break;
+    case PAIR(0, INF):		/* loop x around */
+	s = newstate(v->nfa);
+	NOERR();
+	moveouts(v->nfa, lp, s);
+	moveins(v->nfa, rp, s);
+	EMPTYARC(lp, s);
+	EMPTYARC(s, rp);
+	break;
+    case PAIR(1, 1):		/* no action required */
+	break;
+    case PAIR(1, SOME):		/* do as x{0,n-1}x = (x{1,n-1}|)x */
+	s = newstate(v->nfa);
+	NOERR();
+	moveouts(v->nfa, lp, s);
+	dupnfa(v->nfa, s, rp, lp, s);
+	NOERR();
+	repeat(v, lp, s, 1, n-1);
+	NOERR();
+	EMPTYARC(lp, s);
+	break;
+    case PAIR(1, INF):		/* add loopback arc */
+	s = newstate(v->nfa);
+	s2 = newstate(v->nfa);
+	NOERR();
+	moveouts(v->nfa, lp, s);
+	moveins(v->nfa, rp, s2);
+	EMPTYARC(lp, s);
+	EMPTYARC(s2, rp);
+	EMPTYARC(s2, s);
+	break;
+    case PAIR(SOME, SOME):		/* do as x{m-1,n-1}x */
+	s = newstate(v->nfa);
+	NOERR();
+	moveouts(v->nfa, lp, s);
+	dupnfa(v->nfa, s, rp, lp, s);
+	NOERR();
+	repeat(v, lp, s, m-1, n-1);
+	break;
+    case PAIR(SOME, INF):		/* do as x{m-1,}x */
+	s = newstate(v->nfa);
+	NOERR();
+	moveouts(v->nfa, lp, s);
+	dupnfa(v->nfa, s, rp, lp, s);
+	NOERR();
+	repeat(v, lp, s, m-1, n);
+	break;
+    default:
+	ERR(REG_ASSERT);
+	break;
+    }
+}
+
+/*
+ - bracket - handle non-complemented bracket expression
+ * Also called from cbracket for complemented bracket expressions.
+ ^ static void bracket(struct vars *, struct state *, struct state *);
+ */
+static void
+bracket(
+    struct vars *v,
+    struct state *lp,
+    struct state *rp)
+{
+    assert(SEE('['));
+    NEXT();
+    while (!SEE(']') && !SEE(EOS)) {
+	brackpart(v, lp, rp);
+    }
+    assert(SEE(']') || ISERR());
+    okcolors(v->nfa, v->cm);
+}
+
+/*
+ - cbracket - handle complemented bracket expression
+ * We do it by calling bracket() with dummy endpoints, and then complementing
+ * the result. The alternative would be to invoke rainbow(), and then delete
+ * arcs as the b.e. is seen... but that gets messy.
+ ^ static void cbracket(struct vars *, struct state *, struct state *);
+ */
+static void
+cbracket(
+    struct vars *v,
+    struct state *lp,
+    struct state *rp)
+{
+    struct state *left = newstate(v->nfa);
+    struct state *right = newstate(v->nfa);
+
+    NOERR();
+    bracket(v, left, right);
+    if (v->cflags&REG_NLSTOP) {
+	newarc(v->nfa, PLAIN, v->nlcolor, left, right);
+    }
+    NOERR();
+
+    assert(lp->nouts == 0);	/* all outarcs will be ours */
+
+    /*
+     * Easy part of complementing, and all there is to do since the MCCE code
+     * was removed.
+     */
+
+    colorcomplement(v->nfa, v->cm, PLAIN, left, lp, rp);
+    NOERR();
+    dropstate(v->nfa, left);
+    assert(right->nins == 0);
+    freestate(v->nfa, right);
+    return;
+}
+
+/*
+ - brackpart - handle one item (or range) within a bracket expression
+ ^ static void brackpart(struct vars *, struct state *, struct state *);
+ */
+static void
+brackpart(
+    struct vars *v,
+    struct state *lp,
+    struct state *rp)
+{
+    celt startc, endc;
+    struct cvec *cv;
+    const chr *startp, *endp;
+    chr c;
+
+    /*
+     * Parse something, get rid of special cases, take shortcuts.
+     */
+
+    switch (v->nexttype) {
+    case RANGE:			/* a-b-c or other botch */
+	ERR(REG_ERANGE);
+	return;
+	break;
+    case PLAIN:
+	c = v->nextvalue;
+	NEXT();
+
+	/*
+	 * Shortcut for ordinary chr (not range).
+	 */
+
+	if (!SEE(RANGE)) {
+	    onechr(v, c, lp, rp);
+	    return;
+	}
+	startc = element(v, &c, &c+1);
+	NOERR();
+	break;
+    case COLLEL:
+	startp = v->now;
+	endp = scanplain(v);
+	INSIST(startp < endp, REG_ECOLLATE);
+	NOERR();
+	startc = element(v, startp, endp);
+	NOERR();
+	break;
+    case ECLASS:
+	startp = v->now;
+	endp = scanplain(v);
+	INSIST(startp < endp, REG_ECOLLATE);
+	NOERR();
+	startc = element(v, startp, endp);
+	NOERR();
+	cv = eclass(v, startc, (v->cflags&REG_ICASE));
+	NOERR();
+	dovec(v, cv, lp, rp);
+	return;
+	break;
+    case CCLASS:
+	startp = v->now;
+	endp = scanplain(v);
+	INSIST(startp < endp, REG_ECTYPE);
+	NOERR();
+	cv = cclass(v, startp, endp, (v->cflags&REG_ICASE));
+	NOERR();
+	dovec(v, cv, lp, rp);
+	return;
+	break;
+    default:
+	ERR(REG_ASSERT);
+	return;
+	break;
+    }
+
+    if (SEE(RANGE)) {
+	NEXT();
+	switch (v->nexttype) {
+	case PLAIN:
+	case RANGE:
+	    c = v->nextvalue;
+	    NEXT();
+	    endc = element(v, &c, &c+1);
+	    NOERR();
+	    break;
+	case COLLEL:
+	    startp = v->now;
+	    endp = scanplain(v);
+	    INSIST(startp < endp, REG_ECOLLATE);
+	    NOERR();
+	    endc = element(v, startp, endp);
+	    NOERR();
+	    break;
+	default:
+	    ERR(REG_ERANGE);
+	    return;
+	    break;
+	}
+    } else {
+	endc = startc;
+    }
+
+    /*
+     * Ranges are unportable. Actually, standard C does guarantee that digits
+     * are contiguous, but making that an exception is just too complicated.
+     */
+
+    if (startc != endc) {
+	NOTE(REG_UUNPORT);
+    }
+    cv = range(v, startc, endc, (v->cflags&REG_ICASE));
+    NOERR();
+    dovec(v, cv, lp, rp);
+}
+
+/*
+ - scanplain - scan PLAIN contents of [. etc.
+ * Certain bits of trickery in lex.c know that this code does not try to look
+ * past the final bracket of the [. etc.
+ ^ static const chr *scanplain(struct vars *);
+ */
+static const chr *		/* just after end of sequence */
+scanplain(
+    struct vars *v)
+{
+    const chr *endp;
+
+    assert(SEE(COLLEL) || SEE(ECLASS) || SEE(CCLASS));
+    NEXT();
+
+    endp = v->now;
+    while (SEE(PLAIN)) {
+	endp = v->now;
+	NEXT();
+    }
+
+    assert(SEE(END) || ISERR());
+    NEXT();
+
+    return endp;
+}
+
+/*
+ - onechr - fill in arcs for a plain character, and possible case complements
+ * This is mostly a shortcut for efficient handling of the common case.
+ ^ static void onechr(struct vars *, pchr, struct state *, struct state *);
+ */
+static void
+onechr(
+    struct vars *v,
+    pchr c,
+    struct state *lp,
+    struct state *rp)
+{
+    if (!(v->cflags&REG_ICASE)) {
+	newarc(v->nfa, PLAIN, subcolor(v->cm, c), lp, rp);
+	return;
+    }
+
+    /*
+     * Rats, need general case anyway...
+     */
+
+    dovec(v, allcases(v, c), lp, rp);
+}
+
+/*
+ - dovec - fill in arcs for each element of a cvec
+ ^ static void dovec(struct vars *, struct cvec *, struct state *,
+ ^ 	struct state *);
+ */
+static void
+dovec(
+    struct vars *v,
+    struct cvec *cv,
+    struct state *lp,
+    struct state *rp)
+{
+    chr ch, from, to;
+    const chr *p;
+    int i;
+
+    for (p = cv->chrs, i = cv->nchrs; i > 0; p++, i--) {
+	ch = *p;
+	newarc(v->nfa, PLAIN, subcolor(v->cm, ch), lp, rp);
+    }
+
+    for (p = cv->ranges, i = cv->nranges; i > 0; p += 2, i--) {
+	from = *p;
+	to = *(p+1);
+	if (from <= to) {
+	    subrange(v, from, to, lp, rp);
+	}
+    }
+
+}
+
+/*
+ - wordchrs - set up word-chr list for word-boundary stuff, if needed
+ * The list is kept as a bunch of arcs between two dummy states; it's disposed
+ * of by the unreachable-states sweep in NFA optimization. Does NEXT(). Must
+ * not be called from any unusual lexical context. This should be reconciled
+ * with the \w etc. handling in lex.c, and should be cleaned up to reduce
+ * dependencies on input scanning.
+ ^ static void wordchrs(struct vars *);
+ */
+static void
+wordchrs(
+    struct vars *v)
+{
+    struct state *left, *right;
+
+    if (v->wordchrs != NULL) {
+	NEXT();		/* for consistency */
+	return;
+    }
+
+    left = newstate(v->nfa);
+    right = newstate(v->nfa);
+    NOERR();
+
+    /*
+     * Fine point: implemented with [::], and lexer will set REG_ULOCALE.
+     */
+
+    lexword(v);
+    NEXT();
+    assert(v->savenow != NULL && SEE('['));
+    bracket(v, left, right);
+    assert((v->savenow != NULL && SEE(']')) || ISERR());
+    NEXT();
+    NOERR();
+    v->wordchrs = left;
+}
+
+/*
+ - subre - allocate a subre
+ ^ static struct subre *subre(struct vars *, int, int, struct state *,
+ ^	struct state *);
+ */
+static struct subre *
+subre(
+    struct vars *v,
+    int op,
+    int flags,
+    struct state *begin,
+    struct state *end)
+{
+    struct subre *ret = v->treefree;
+
+    if (ret != NULL) {
+	v->treefree = ret->left;
+    } else {
+	ret = (struct subre *) MALLOC(sizeof(struct subre));
+	if (ret == NULL) {
+	    ERR(REG_ESPACE);
+	    return NULL;
+	}
+	ret->chain = v->treechain;
+	v->treechain = ret;
+    }
+
+    assert(strchr("=b|.*(", op) != NULL);
+
+    ret->op = op;
+    ret->flags = flags;
+    ret->id = 0;		/* will be assigned later */
+    ret->subno = 0;
+    ret->min = ret->max = 1;
+    ret->left = NULL;
+    ret->right = NULL;
+    ret->begin = begin;
+    ret->end = end;
+    ZAPCNFA(ret->cnfa);
+
+    return ret;
+}
+
+/*
+ - freesubre - free a subRE subtree
+ ^ static void freesubre(struct vars *, struct subre *);
+ */
+static void
+freesubre(
+    struct vars *v,		/* might be NULL */
+    struct subre *sr)
+{
+    if (sr == NULL) {
+	return;
+    }
+
+    if (sr->left != NULL) {
+	freesubre(v, sr->left);
+    }
+    if (sr->right != NULL) {
+	freesubre(v, sr->right);
+    }
+
+    freesrnode(v, sr);
+}
+
+/*
+ - freesrnode - free one node in a subRE subtree
+ ^ static void freesrnode(struct vars *, struct subre *);
+ */
+static void
+freesrnode(
+    struct vars *v,		/* might be NULL */
+    struct subre *sr)
+{
+    if (sr == NULL) {
+	return;
+    }
+
+    if (!NULLCNFA(sr->cnfa)) {
+	freecnfa(&sr->cnfa);
+    }
+    sr->flags = 0;
+
+    if (v != NULL && v->treechain != NULL) {
+	/* we're still parsing, maybe we can reuse the subre */
+	sr->left = v->treefree;
+	v->treefree = sr;
+    } else {
+	FREE(sr);
+    }
+}
+
+/*
+ - optst - optimize a subRE subtree
+ ^ static void optst(struct vars *, struct subre *);
+ */
+static void
+optst(
+    struct vars *v,
+    struct subre *t)
+{
+    /*
+     * DGP (2007-11-13): I assume it was the programmer's intent to eventually
+     * come back and add code to optimize subRE trees, but the routine coded
+     * just spends effort traversing the tree and doing nothing. We can do
+     * nothing with less effort.
+     */
+
+    return;
+}
+
+/*
+ - numst - number tree nodes (assigning "id" indexes)
+ ^ static int numst(struct subre *, int);
+ */
+static int			/* next number */
+numst(
+    struct subre *t,
+    int start)			/* starting point for subtree numbers */
+{
+    int i;
+
+    assert(t != NULL);
+
+    i = start;
+    t->id = (short) i++;
+    if (t->left != NULL) {
+	i = numst(t->left, i);
+    }
+    if (t->right != NULL) {
+	i = numst(t->right, i);
+    }
+    return i;
+}
+
+/*
+ - markst - mark tree nodes as INUSE
+ * Note: this is a great deal more subtle than it looks.  During initial
+ * parsing of a regex, all subres are linked into the treechain list;
+ * discarded ones are also linked into the treefree list for possible reuse.
+ * After we are done creating all subres required for a regex, we run markst()
+ * then cleanst(), which results in discarding all subres not reachable from
+ * v->tree.  We then clear v->treechain, indicating that subres must be found
+ * by descending from v->tree.  This changes the behavior of freesubre(): it
+ * will henceforth FREE() unwanted subres rather than sticking them into the
+ * treefree list.  (Doing that any earlier would result in dangling links in
+ * the treechain list.)  This all means that freev() will clean up correctly
+ * if invoked before or after markst()+cleanst(); but it would not work if
+ * called partway through this state conversion, so we mustn't error out
+ * in or between these two functions.
+ ^ static void markst(struct subre *);
+ */
+static void
+markst(
+    struct subre *t)
+{
+    assert(t != NULL);
+
+    t->flags |= INUSE;
+    if (t->left != NULL) {
+	markst(t->left);
+    }
+    if (t->right != NULL) {
+	markst(t->right);
+    }
+}
+
+/*
+ - cleanst - free any tree nodes not marked INUSE
+ ^ static void cleanst(struct vars *);
+ */
+static void
+cleanst(
+    struct vars *v)
+{
+    struct subre *t;
+    struct subre *next;
+
+    for (t = v->treechain; t != NULL; t = next) {
+	next = t->chain;
+	if (!(t->flags&INUSE)) {
+	    FREE(t);
+	}
+    }
+    v->treechain = NULL;
+    v->treefree = NULL;		/* just on general principles */
+}
+
+/*
+ - nfatree - turn a subRE subtree into a tree of compacted NFAs
+ ^ static long nfatree(struct vars *, struct subre *, FILE *);
+ */
+static long			/* optimize results from top node */
+nfatree(
+    struct vars *v,
+    struct subre *t,
+    FILE *f)			/* for debug output */
+{
+    assert(t != NULL && t->begin != NULL);
+
+    if (t->left != NULL) {
+	(DISCARD) nfatree(v, t->left, f);
+    }
+    if (t->right != NULL) {
+	(DISCARD) nfatree(v, t->right, f);
+    }
+
+    return nfanode(v, t, f);
+}
+
+/*
+ - nfanode - do one NFA for nfatree
+ ^ static long nfanode(struct vars *, struct subre *, FILE *);
+ */
+static long			/* optimize results */
+nfanode(
+    struct vars *v,
+    struct subre *t,
+    FILE *f)			/* for debug output */
+{
+    struct nfa *nfa;
+    long ret = 0;
+    char idbuf[50];
+
+    assert(t->begin != NULL);
+
+    if (f != NULL) {
+	fprintf(f, "\n\n\n========= TREE NODE %s ==========\n",
+		stid(t, idbuf, sizeof(idbuf)));
+    }
+    nfa = newnfa(v, v->cm, v->nfa);
+    NOERRZ();
+    dupnfa(nfa, t->begin, t->end, nfa->init, nfa->final);
+    if (!ISERR()) {
+	specialcolors(nfa);
+	ret = optimize(nfa, f);
+    }
+    if (!ISERR()) {
+	compact(nfa, &t->cnfa);
+    }
+
+    freenfa(nfa);
+    return ret;
+}
+
+/*
+ - newlacon - allocate a lookahead-constraint subRE
+ ^ static int newlacon(struct vars *, struct state *, struct state *, int);
+ */
+static int			/* lacon number */
+newlacon(
+    struct vars *v,
+    struct state *begin,
+    struct state *end,
+    int pos)
+{
+    int n;
+    struct subre *newlacons;
+    struct subre *sub;
+
+    if (v->nlacons == 0) {
+	n = 1;		/* skip 0th */
+	newlacons = (struct subre *) MALLOC(2 * sizeof(struct subre));
+    } else {
+	n = v->nlacons;
+	newlacons = (struct subre *) REALLOC(v->lacons,
+					     (n + 1) * sizeof(struct subre));
+    }
+
+    if (newlacons == NULL) {
+	ERR(REG_ESPACE);
+	return 0;
+    }
+
+    v->lacons = newlacons;
+    v->nlacons = n + 1;
+    sub = &v->lacons[n];
+    sub->begin = begin;
+    sub->end = end;
+    sub->subno = pos;
+    ZAPCNFA(sub->cnfa);
+    return n;
+}
+
+/*
+ - freelacons - free lookahead-constraint subRE vector
+ ^ static void freelacons(struct subre *, int);
+ */
+static void
+freelacons(
+    struct subre *subs,
+    int n)
+{
+    struct subre *sub;
+    int i;
+
+    assert(n > 0);
+    for (sub=subs+1, i=n-1; i>0; sub++, i--) {	/* no 0th */
+	if (!NULLCNFA(sub->cnfa)) {
+	    freecnfa(&sub->cnfa);
+	}
+    }
+    FREE(subs);
+}
+
+/*
+ - rfree - free a whole RE (insides of regfree)
+ ^ static void rfree(regex_t *);
+ */
+static void
+rfree(
+    regex_t *re)
+{
+    struct guts *g;
+
+    if (re == NULL || re->re_magic != REMAGIC) {
+	return;
+    }
+
+    re->re_magic = 0;	/* invalidate RE */
+    g = (struct guts *) re->re_guts;
+    re->re_guts = NULL;
+    re->re_fns = NULL;
+    if (g != NULL) {
+	g->magic = 0;
+	freecm(&g->cmap);
+	if (g->tree != NULL) {
+	    freesubre(NULL, g->tree);
+	}
+	if (g->lacons != NULL) {
+	    freelacons(g->lacons, g->nlacons);
+	}
+	if (!NULLCNFA(g->search)) {
+	    freecnfa(&g->search);
+	}
+	FREE(g);
+    }
+}
+
+/*
+ - dump - dump an RE in human-readable form
+ ^ static void dump(regex_t *, FILE *);
+ */
+static void
+dump(
+    regex_t *re,
+    FILE *f)
+{
+#ifdef REG_DEBUG
+    struct guts *g;
+    int i;
+
+    if (re->re_magic != REMAGIC) {
+	fprintf(f, "bad magic number (0x%x not 0x%x)\n",
+		re->re_magic, REMAGIC);
+    }
+    if (re->re_guts == NULL) {
+	fprintf(f, "NULL guts!!!\n");
+	return;
+    }
+    g = (struct guts *) re->re_guts;
+    if (g->magic != GUTSMAGIC) {
+	fprintf(f, "bad guts magic number (0x%x not 0x%x)\n",
+		g->magic, GUTSMAGIC);
+    }
+
+    fprintf(f, "\n\n\n========= DUMP ==========\n");
+    fprintf(f, "nsub %d, info 0%lo, csize %d, ntree %d\n",
+	    (int) re->re_nsub, re->re_info, re->re_csize, g->ntree);
+
+    dumpcolors(&g->cmap, f);
+    if (!NULLCNFA(g->search)) {
+	fprintf(f, "\nsearch:\n");
+	dumpcnfa(&g->search, f);
+    }
+    for (i = 1; i < g->nlacons; i++) {
+	fprintf(f, "\nla%d (%s):\n", i,
+		(g->lacons[i].subno) ? "positive" : "negative");
+	dumpcnfa(&g->lacons[i].cnfa, f);
+    }
+    fprintf(f, "\n");
+    dumpst(g->tree, f, 0);
+#endif
+}
+
+/*
+ - dumpst - dump a subRE tree
+ ^ static void dumpst(struct subre *, FILE *, int);
+ */
+static void
+dumpst(
+    struct subre *t,
+    FILE *f,
+    int nfapresent)		/* is the original NFA still around? */
+{
+    if (t == NULL) {
+	fprintf(f, "null tree\n");
+    } else {
+	stdump(t, f, nfapresent);
+    }
+    fflush(f);
+}
+
+/*
+ - stdump - recursive guts of dumpst
+ ^ static void stdump(struct subre *, FILE *, int);
+ */
+static void
+stdump(
+    struct subre *t,
+    FILE *f,
+    int nfapresent)		/* is the original NFA still around? */
+{
+    char idbuf[50];
+
+    fprintf(f, "%s. `%c'", stid(t, idbuf, sizeof(idbuf)), t->op);
+    if (t->flags&LONGER) {
+	fprintf(f, " longest");
+    }
+    if (t->flags&SHORTER) {
+	fprintf(f, " shortest");
+    }
+    if (t->flags&MIXED) {
+	fprintf(f, " hasmixed");
+    }
+    if (t->flags&CAP) {
+	fprintf(f, " hascapture");
+    }
+    if (t->flags&BACKR) {
+	fprintf(f, " hasbackref");
+    }
+    if (!(t->flags&INUSE)) {
+	fprintf(f, " UNUSED");
+    }
+    if (t->subno != 0) {
+	fprintf(f, " (#%d)", t->subno);
+    }
+    if (t->min != 1 || t->max != 1) {
+	fprintf(f, " {%d,", t->min);
+	if (t->max != DUPINF) {
+	    fprintf(f, "%d", t->max);
+	}
+	fprintf(f, "}");
+    }
+    if (nfapresent) {
+	fprintf(f, " %ld-%ld", (long)t->begin->no, (long)t->end->no);
+    }
+    if (t->left != NULL) {
+	fprintf(f, " L:%s", stid(t->left, idbuf, sizeof(idbuf)));
+    }
+    if (t->right != NULL) {
+	fprintf(f, " R:%s", stid(t->right, idbuf, sizeof(idbuf)));
+    }
+    if (!NULLCNFA(t->cnfa)) {
+	fprintf(f, "\n");
+	dumpcnfa(&t->cnfa, f);
+    }
+    fprintf(f, "\n");
+    if (t->left != NULL) {
+	stdump(t->left, f, nfapresent);
+    }
+    if (t->right != NULL) {
+	stdump(t->right, f, nfapresent);
+    }
+}
+
+/*
+ - stid - identify a subtree node for dumping
+ ^ static const char *stid(struct subre *, char *, size_t);
+ */
+static const char *			/* points to buf or constant string */
+stid(
+    struct subre *t,
+    char *buf,
+    size_t bufsize)
+{
+    /*
+     * Big enough for hex int or decimal t->id?
+     */
+
+    if (bufsize < sizeof(void*)*2 + 3 || bufsize < sizeof(t->id)*3 + 1) {
+	return "unable";
+    }
+    if (t->id != 0) {
+	sprintf(buf, "%d", t->id);
+    } else {
+	sprintf(buf, "%p", t);
+    }
+    return buf;
+}
+
+#include "regc_lex.c"
+#include "regc_color.c"
+#include "regc_nfa.c"
+#include "regc_cvec.c"
+#include "regc_locale.c"
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */