More safety, also after terms and nonterminals.
This commit is contained in:
ceriel
parent
67beb0c4d5
commit
d07e8114c6
4 changed files with 58 additions and 51 deletions
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@ -204,13 +204,16 @@ check(p) register p_gram p; {
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switch (g_gettype(p)) {
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case EORULE :
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return;
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case NONTERM :
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if (g_getnpar(p)!=((nonterms[g_getnont(p)].n_flags&077) >> 3)){
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case NONTERM : {
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register p_nont n;
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n = &nonterms[g_getnont(p)];
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if (g_getnpar(p) != getntparams(n)) {
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error(p->g_lineno,
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"Call of %s : parameter count mismatch",
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(min_nt_ent+g_getnont(p))->h_name);
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}
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break;
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break; }
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case TERM : {
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register p_term q;
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@ -670,28 +670,28 @@ co_safes() {
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/*
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* Don't know anything yet
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*/
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setntsafe(&(p->n_flags), NOSAFETY);
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setntsafe(p, NOSAFETY);
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setntout(p, NOSAFETY);
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}
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for (st = start; st; st = st->ff_next) {
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/*
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* But start symbols are called with lookahead done
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*/
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p = st->ff_nont;
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setntsafe(&(p->n_flags),SCANDONE);
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setntsafe(p,SCANDONE);
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}
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change = 1;
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while (change) {
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change = 0;
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for (p = nonterms; p < maxnt; p++) {
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i = getntsafe(p->n_flags);
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i = getntsafe(p);
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if (i == NOSAFETY) {
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change = 1;
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continue;
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}
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if (do_safes(p->n_rule, i) == 2 &&
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!(p->n_flags & NNOSCAN)) {
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p->n_flags |= NNOSCAN;
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i = do_safes(p->n_rule, i);
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if (getntout(p) != i) {
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change = 1;
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setntout(p, i);
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}
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}
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}
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@ -705,8 +705,6 @@ do_safes(p,safe) register p_gram p; {
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*/
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register retval;
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if (safe == NOSCANDONE) retval = 2;
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else retval = 1;
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for (;;) {
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switch (g_gettype(p)) {
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case ACTION:
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@ -724,10 +722,10 @@ do_safes(p,safe) register p_gram p; {
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rep = r_getkind(&(q->t_reps));
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retval = do_safes(q->t_rule,
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t_safety(rep,i,q->t_flags&PERSISTENT,safe));
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if (retval == 2 && (!(q->t_flags & TNOSCAN))) {
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q->t_flags |= TNOSCAN;
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if (retval != gettout(q)) {
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settout(q, retval);
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}
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safe = t_after(rep, i, q->t_flags & TNOSCAN);
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safe = t_after(rep, i, gettout(q));
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break; }
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case ALTERNATION : {
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register p_link l;
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@ -736,51 +734,53 @@ do_safes(p,safe) register p_gram p; {
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f = 1;
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while (g_gettype(p) == ALTERNATION) {
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l = (p_link) pentry[g_getcont(p)];
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if (safe && (l->l_flag & DEF)) {
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if (safe > SAFE && (l->l_flag & DEF)) {
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i = do_safes(l->l_rule,SAFESCANDONE);
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}
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else i = do_safes(l->l_rule,SAFE);
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if (f) retval = i;
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else retval &= i;
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else if (i != retval) {
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if (i == NOSCANDONE ||
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retval == NOSCANDONE) {
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retval = SCANDONE;
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}
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else if (i > retval) retval = i;
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}
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p++;
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f = 0;
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}
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return retval; }
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case NONTERM : {
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register p_nont n;
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int nsafe, osafe;;
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int nsafe, osafe;
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n = &nonterms[g_getnont(p)];
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nsafe = getntsafe(n->n_flags);
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nsafe = getntsafe(n);
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osafe = safe;
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if (!(n->n_flags & NNOSCAN)) {
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safe = SCANDONE;
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}
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else safe = NOSCANDONE;
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safe = getntout(n);
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if (safe == NOSAFETY) safe = SCANDONE;
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if (osafe == nsafe) break;
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if (nsafe == NOSAFETY) {
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change = 1;
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setntsafe(&(n->n_flags), osafe);
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setntsafe(n, osafe);
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break;
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}
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if (osafe == NOSCANDONE || nsafe == NOSCANDONE) {
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if (nsafe != SCANDONE) {
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change = 1;
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setntsafe(&(n->n_flags), SCANDONE);
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setntsafe(n, SCANDONE);
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}
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break;
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}
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if (osafe > nsafe) {
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setntsafe(&(n->n_flags), osafe);
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setntsafe(n, osafe);
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change = 1;
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}
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break; }
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case EORULE :
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return retval;
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return safe;
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}
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p++;
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if (safe == NOSCANDONE) retval = 2;
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else retval = 1;
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}
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}
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@ -814,10 +814,13 @@ t_safety(rep, count, persistent, safety) {
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/* NOTREACHED */
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}
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t_after(rep, count, noscan) {
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t_after(rep, count, outsafety) {
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if (count == 0 && (rep == STAR || rep == PLUS)) {
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return SAFESCANDONE;
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}
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if (rep == FIXED && noscan) return NOSCANDONE;
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return SCANDONE;
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if (rep != FIXED) {
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if (outsafety <= SAFESCANDONE) return SAFESCANDONE;
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return SCANDONE;
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}
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return outsafety;
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}
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@ -173,7 +173,7 @@ genrecovery() {
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fprintf(f, "\tL%d_%s();\n",
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st->ff_nont-nonterms,
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(min_nt_ent+(st->ff_nont-nonterms))->h_name);
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if (st->ff_nont->n_flags & NNOSCAN) {
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if (getntout(st->ff_nont) == NOSCANDONE) {
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fputs("\tLLscan(EOFILE);\n",f);
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}
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else fputs("\tif (LLsymb != EOFILE) LLerror(EOFILE);\n",f);
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@ -240,7 +240,7 @@ generate(f) p_file f; {
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else fputs(") {\n", fd);
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fputs("register struct LLxx *LLx = &LLxx;\n#ifdef lint\nLLx=LLx;\n#endif\n", fd);
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if (p->n_flags & LOCALS) getaction(1);
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i = getntsafe(p->n_flags);
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i = getntsafe(p);
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mustpop = 0;
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if (g_gettype(p->n_rule) == ALTERNATION) {
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mustpop = 1;
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@ -252,7 +252,8 @@ generate(f) p_file f; {
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nlabel = 1;
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rulecode(p->n_rule,
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i,
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!(p->n_flags & NNOSCAN), mustpop);
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getntout(p) != NOSCANDONE,
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mustpop);
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fputs(c_close, fd);
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}
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}
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@ -443,7 +444,7 @@ rulecode(p,safety,mustscan,mustpop) register p_gram p; {
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n = &nonterms[g_getnont(p)];
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t= min_nt_ent+(n-nonterms);
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if (safety == NOSCANDONE &&
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getntsafe(n->n_flags) < NOSCANDONE) fputs(c_read, f);
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getntsafe(n) < NOSCANDONE) fputs(c_read, f);
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if (toplevel == 0 &&
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g_gettype(n->n_rule) != ALTERNATION) {
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fputs(c_LLptrmin, f);
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@ -453,8 +454,7 @@ rulecode(p,safety,mustscan,mustpop) register p_gram p; {
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fprintf(f,"L%d_%s(",n-nonterms, t->h_name);
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if (params) getaction(0);
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fputs(");\n",f);
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safety = NOSCANDONE;
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if (!(n->n_flags & NNOSCAN)) safety = SCANDONE;
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safety = getntout(n);
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break; }
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case TERM :
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safety = codeforterm((p_term) pentry[g_getcont(p)],
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@ -707,13 +707,11 @@ codeforterm(q,safety,toplevel) register p_term q; {
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register int i;
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register int rep;
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int persistent;
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int noscan;
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f = fpars;
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i = r_getnum(&(q->t_reps));
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rep = r_getkind(&(q->t_reps));
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persistent = (q->t_flags & PERSISTENT);
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noscan = (q->t_flags & TNOSCAN);
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if (safety == NOSCANDONE && (rep != FIXED || i == 0)) {
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fputs(c_read, f);
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if (rep == FIXED && g_gettype(q->t_rule) != ALTERNATION) {
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@ -726,7 +724,7 @@ codeforterm(q,safety,toplevel) register p_term q; {
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fputs("for (;;) {\nif (!LL_i--) {\nLLptr++;\n", f);
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fputs("break;\n}\n", f);
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if (rep == FIXED) {
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if (noscan && safety == NOSCANDONE) {
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if (gettout(q) == NOSCANDONE && safety == NOSCANDONE) {
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fputs(c_read,f);
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}
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}
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@ -739,7 +737,7 @@ codeforterm(q,safety,toplevel) register p_term q; {
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genifhead(q,rep);
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}
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rulecode(q->t_rule,t_safety(rep,i,persistent,safety),
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rep != FIXED || !noscan,
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rep != FIXED || gettout(q) != NOSCANDONE,
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rep == FIXED && i == 0 && g_gettype(q->t_rule) == ALTERNATION);
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/* in the case of '+', the if is after the code for the rule */
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if (rep == PLUS) {
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@ -761,7 +759,7 @@ codeforterm(q,safety,toplevel) register p_term q; {
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fputs(c_close, f);/* Close Register ... */
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}
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}
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return t_after(rep, i, noscan);
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return t_after(rep, i, gettout(q));
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}
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STATIC
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@ -108,15 +108,11 @@ typedef struct gram {
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*/
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typedef struct {
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short n_flags; /* low order three bits are reserved
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* for "safety" information,
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* the next three bits are reserved for
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* the parameter count
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*/
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# define getntsafe(f) ((f)&07)
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# define setntsafe(p,i) {assert(((unsigned)(i))<=7);*(p)&=~07;*(p)|=(i);}
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# define getntparams(p) ((p)->n_flags&07)
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# define setntparams(p,i) {assert(((unsigned)(i))<=7);(p)->n_flags&=~07;(p)->n_flags|=(i);}
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# define RECURSIVE 00100 /* Set if the default rule is recursive */
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# define NNOSCAN 00200 /* Set if the nonterminal does not scan ahead */
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# define CONTIN 00400 /* continuation already computed? */
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# define BUSY 01000 /* or are we busy computing it? */
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# define PARAMS 02000 /* tells if a nonterminal has parameters */
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@ -125,8 +121,14 @@ typedef struct {
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# define LOCALS 020000 /* local declarations ? */
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# define REACHABLE 040000 /* can this nonterminal be reached ? */
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# define VERBOSE 0100000 /* Set if in LL.output file */
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char n_insafety;
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char n_outsafety;
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# define getntsafe(p) ((p)->n_insafety)
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# define setntsafe(p,i) {assert(((unsigned)(i))<=NOSAFETY);(p)->n_insafety=(i);}
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# define getntout(p) ((p)->n_outsafety)
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# define setntout(p,i) {assert(((unsigned)(i))<=NOSAFETY);(p)->n_outsafety=(i);}
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short n_count; /* pieces of code before this rule */
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int n_lineno; /* declared on line ... */
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short n_lineno; /* declared on line ... */
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p_gram n_rule; /* pointer to right hand side of rule */
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union {
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p_set n_f; /* ptr to "first" set */
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@ -192,11 +194,12 @@ typedef short t_reps,*p_reps;
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typedef struct term {
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t_reps t_reps; /* repeats ? */
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short t_flags;
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# define gettout(q) ((q)->t_flags&07)
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# define settout(q,i) {assert(((unsigned)(i))<=NOSAFETY);(q)->t_flags&=~07;(q)->t_flags|=i;}
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# define PERSISTENT 010 /* Set if this term has %persistent */
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# define RESOLVER 020 /* Set if this term has %while */
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# define EMPTYFIRST 0100 /* Error, empty first */
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# define EMPTYTERM 0200 /* Error, term can produce empty */
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# define TNOSCAN 0400 /* Set if this term does not scan ahead */
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/* # define NOCONF 01000 see link structure */
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p_gram t_rule; /* pointer to this term */
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