libregex: implement \` and \' (begin-of-subj, end-of-subj)
These are GNU extensions, generally equivalent to ^ and $ except that the new syntax will not match beginning of line after the first in a multi-line expression or the end of line before absolute last in a multi-line expression.
This commit is contained in:
Kyle Evans
parent
7518fb346f
commit
ca53e5aedf
@ -109,7 +109,7 @@ static int matcher(struct re_guts *g, const char *string, size_t nmatch, regmatc
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static const char *dissect(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst);
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static const char *backref(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst, sopno lev, int);
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static const char *walk(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst, bool fast);
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static states step(struct re_guts *g, sopno start, sopno stop, states bef, wint_t ch, states aft);
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static states step(struct re_guts *g, sopno start, sopno stop, states bef, wint_t ch, states aft, int sflags);
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#define MAX_RECURSION 100
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#define BOL (OUT-1)
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#define EOL (BOL-1)
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@ -119,6 +119,10 @@ static states step(struct re_guts *g, sopno start, sopno stop, states bef, wint_
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#define EOW (BOL-5)
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#define BADCHAR (BOL-6)
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#define NONCHAR(c) ((c) <= OUT)
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/* sflags */
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#define SBOS 0x0001
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#define SEOS 0x0002
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#ifdef REDEBUG
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static void print(struct match *m, const char *caption, states st, int ch, FILE *d);
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#endif
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@ -457,6 +461,8 @@ dissect(struct match *m,
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case OEOL:
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case OBOW:
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case OEOW:
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case OBOS:
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case OEOS:
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break;
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case OANY:
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case OANYOF:
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@ -657,6 +663,18 @@ backref(struct match *m,
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if (wc == BADCHAR || !CHIN(cs, wc))
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return(NULL);
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break;
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case OBOS:
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if (sp == m->beginp && (m->eflags & REG_NOTBOL) == 0)
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{ /* yes */ }
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else
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return(NULL);
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break;
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case OEOS:
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if (sp == m->endp && (m->eflags & REG_NOTEOL) == 0)
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{ /* yes */ }
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else
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return(NULL);
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break;
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case OBOL:
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if ((sp == m->beginp && !(m->eflags®_NOTBOL)) ||
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(sp > m->offp && sp < m->endp &&
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@ -819,15 +837,16 @@ walk(struct match *m, const char *start, const char *stop, sopno startst,
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wint_t c;
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wint_t lastc; /* previous c */
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wint_t flagch;
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int i;
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int i, sflags;
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const char *matchp; /* last p at which a match ended */
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size_t clen;
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sflags = 0;
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AT("slow", start, stop, startst, stopst);
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CLEAR(st);
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SET1(st, startst);
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SP("sstart", st, *p);
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st = step(m->g, startst, stopst, st, NOTHING, st);
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st = step(m->g, startst, stopst, st, NOTHING, st, sflags);
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if (fast)
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ASSIGN(fresh, st);
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matchp = NULL;
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@ -844,6 +863,7 @@ walk(struct match *m, const char *start, const char *stop, sopno startst,
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for (;;) {
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/* next character */
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lastc = c;
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sflags = 0;
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if (p == m->endp) {
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c = OUT;
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clen = 0;
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@ -866,9 +886,20 @@ walk(struct match *m, const char *start, const char *stop, sopno startst,
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flagch = (flagch == BOL) ? BOLEOL : EOL;
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i += m->g->neol;
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}
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if (lastc == OUT && (m->eflags & REG_NOTBOL) == 0) {
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sflags |= SBOS;
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/* Step one more for BOS. */
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i++;
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}
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if (c == OUT && (m->eflags & REG_NOTEOL) == 0) {
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sflags |= SEOS;
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/* Step one more for EOS. */
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i++;
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}
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if (i != 0) {
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for (; i > 0; i--)
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st = step(m->g, startst, stopst, st, flagch, st);
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st = step(m->g, startst, stopst, st, flagch, st,
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sflags);
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SP("sboleol", st, c);
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}
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@ -882,7 +913,7 @@ walk(struct match *m, const char *start, const char *stop, sopno startst,
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flagch = EOW;
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}
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if (flagch == BOW || flagch == EOW) {
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st = step(m->g, startst, stopst, st, flagch, st);
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st = step(m->g, startst, stopst, st, flagch, st, sflags);
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SP("sboweow", st, c);
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}
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@ -903,9 +934,10 @@ walk(struct match *m, const char *start, const char *stop, sopno startst,
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else
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ASSIGN(st, empty);
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assert(c != OUT);
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st = step(m->g, startst, stopst, tmp, c, st);
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st = step(m->g, startst, stopst, tmp, c, st, sflags);
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SP("saft", st, c);
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assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
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assert(EQ(step(m->g, startst, stopst, st, NOTHING, st, sflags),
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st));
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p += clen;
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}
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@ -939,7 +971,8 @@ step(struct re_guts *g,
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sopno stop, /* state after stop state within strip */
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states bef, /* states reachable before */
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wint_t ch, /* character or NONCHAR code */
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states aft) /* states already known reachable after */
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states aft, /* states already known reachable after */
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int sflags) /* state flags */
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{
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cset *cs;
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sop s;
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@ -960,6 +993,14 @@ step(struct re_guts *g,
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if (ch == OPND(s))
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FWD(aft, bef, 1);
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break;
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case OBOS:
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if ((ch == BOL || ch == BOLEOL) && (sflags & SBOS) != 0)
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FWD(aft, bef, 1);
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break;
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case OEOS:
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if ((ch == EOL || ch == BOLEOL) && (sflags & SEOS) != 0)
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FWD(aft, bef, 1);
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break;
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case OBOL:
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if (ch == BOL || ch == BOLEOL)
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FWD(aft, bef, 1);
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@ -480,6 +480,12 @@ p_ere_exp(struct parse *p, struct branchc *bc)
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if (p->gnuext) {
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handled = 1;
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switch (wc) {
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case '`':
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EMIT(OBOS, 0);
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break;
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case '\'':
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EMIT(OEOS, 0);
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break;
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case 'W':
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case 'w':
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case 'S':
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@ -833,6 +839,12 @@ p_simp_re(struct parse *p, struct branchc *bc)
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if (p->gnuext) {
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handled = true;
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switch (c) {
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case BACKSL|'`':
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EMIT(OBOS, 0);
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break;
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case BACKSL|'\'':
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EMIT(OEOS, 0);
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break;
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case BACKSL|'W':
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case BACKSL|'w':
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case BACKSL|'S':
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@ -1878,6 +1890,8 @@ findmust(struct parse *p, struct re_guts *g)
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case OEOW:
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case OBOL:
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case OEOL:
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case OBOS:
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case OEOS:
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case O_QUEST:
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case O_CH:
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case OEND:
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@ -104,6 +104,8 @@ typedef unsigned long sopno;
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#define O_CH (18L<<OPSHIFT) /* end choice back to OOR1 */
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#define OBOW (19L<<OPSHIFT) /* begin word - */
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#define OEOW (20L<<OPSHIFT) /* end word - */
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#define OBOS (21L<<OPSHIFT) /* begin subj. - */
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#define OEOS (22L<<OPSHIFT) /* end subj. - */
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/*
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* Structures for [] character-set representation.
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@ -25,8 +25,12 @@ a\|b\|c b abc a
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#\B[abc]\B & <abc> b
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#\B[abc]+ - <abc> bc
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#\B[abc]\+ b <abc> bc
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#\`abc\' & abc abc
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#\`.+\' - abNc abNc
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#\`.\+\' b abNc abNc
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#(\`a) - Na
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#(a\') - aN
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\`abc & abc abc
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abc\' & abc abc
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\`abc\' & abc abc
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\`.+\' - abNc abNc
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\`.\+\' b abNc abNc
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(\`a) - Na
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(a\`) - aN
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(a\') - aN
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(\'a) - Na
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