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* src/print.c (state_default_rule_compute): New, extracted from...
(print_reductions): here. Pessimize, but clarify the code. * tests/conflicts.at (Defaulted Conflicted Reduction): New.
This commit is contained in:
Akim Demaille
229
src/print.c
229
src/print.c
@@ -165,138 +165,148 @@ print_gotos (FILE *out, state_t *state)
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}
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}
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/*----------------------------------------------------------.
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| Return the default rule of this STATE if it has one, NULL |
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| otherwise. |
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`----------------------------------------------------------*/
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static rule_t *
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state_default_rule_compute (state_t *state)
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{
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reductions_t *redp = state->reductions;
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rule_t *default_rule = NULL;
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int cmax = 0;
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int i;
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/* No need for a lookahead. */
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if (state->consistent)
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return &rules[redp->rules[0]];
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/* 1. Each reduction is possibly masked by the lookaheads on which
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we shift (S/R conflicts)... */
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bitset_zero (shiftset);
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{
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shifts_t *shiftp = state->shifts;
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for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++)
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if (!SHIFT_IS_DISABLED (shiftp, i))
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{
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/* If this state has a shift for the error token, don't use a
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default rule. */
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if (SHIFT_IS_ERROR (shiftp, i))
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return NULL;
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bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
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}
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}
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/* 2. Each reduction is possibly masked by the lookaheads on which
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we raise an error (due to %nonassoc). */
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{
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errs_t *errp = state->errs;
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for (i = 0; i < errp->nerrs; i++)
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if (errp->errs[i])
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bitset_set (shiftset, errp->errs[i]);
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}
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for (i = 0; i < state->nlookaheads; ++i)
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{
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int count = 0;
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/* How many non-masked lookaheads are there for this reduction?
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*/
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bitset_andn (lookaheadset, state->lookaheads[i], shiftset);
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count = bitset_count (lookaheadset);
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if (count > cmax)
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{
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cmax = count;
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default_rule = state->lookaheads_rule[i];
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}
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/* 3. And finally, each reduction is possibly masked by previous
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reductions (in R/R conflicts, we keep the first reductions).
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*/
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bitset_or (shiftset, shiftset, state->lookaheads[i]);
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}
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return default_rule;
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}
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/*----------------------------------------------------.
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| Report on OUT the reduction actions of this STATE. |
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`----------------------------------------------------*/
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static void
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print_reductions (FILE *out, state_t *state)
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{
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int i;
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shifts_t *shiftp = state->shifts;
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reductions_t *redp = state->reductions;
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errs_t *errp = state->errs;
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int nodefault = 0;
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rule_t *default_rule = NULL;
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if (redp->nreds == 0)
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return;
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if (state->consistent)
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{
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int rule = redp->rules[0];
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symbol_number_t symbol = rules[rule].lhs->number;
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fprintf (out, _(" $default\treduce using rule %d (%s)\n\n"),
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rule - 1, symbol_tag_get (symbols[symbol]));
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return;
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}
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default_rule = state_default_rule_compute (state);
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bitset_zero (shiftset);
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for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++)
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if (!SHIFT_IS_DISABLED (shiftp, i))
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{
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/* if this state has a shift for the error token, don't use a
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default rule. */
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if (SHIFT_IS_ERROR (shiftp, i))
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nodefault = 1;
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bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
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}
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bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
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for (i = 0; i < errp->nerrs; i++)
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if (errp->errs[i])
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bitset_set (shiftset, errp->errs[i]);
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if (state->nlookaheads == 1 && !nodefault)
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for (i = 0; i < ntokens; i++)
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{
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rule_t *default_rule = state->lookaheads_rule[0];
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int j;
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int defaulted = 0;
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int count = bitset_test (shiftset, i);
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bitset_and (lookaheadset, state->lookaheads[0], shiftset);
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BITSET_EXECUTE (lookaheadset, 0, i,
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{
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fprintf (out, _(" %-4s\t[reduce using rule %d (%s)]\n"),
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symbol_tag_get (symbols[i]),
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default_rule->number - 1,
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symbol_tag_get_n (default_rule->lhs, 1));
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});
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fprintf (out, _(" $default\treduce using rule %d (%s)\n\n"),
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default_rule->number - 1,
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symbol_tag_get (default_rule->lhs));
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}
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else if (state->nlookaheads >= 1)
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{
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int cmax = 0;
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int default_LA = -1;
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rule_t *default_rule = NULL;
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if (!nodefault)
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for (i = 0; i < state->nlookaheads; ++i)
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for (j = 0; j < state->nlookaheads; ++j)
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if (bitset_test (state->lookaheads[j], i))
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{
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int count = 0;
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bitset_andn (lookaheadset, state->lookaheads[i], shiftset);
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count = bitset_count (lookaheadset);
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if (count > cmax)
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if (count == 0)
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{
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cmax = count;
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default_LA = i;
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default_rule = state->lookaheads_rule[i];
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}
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bitset_or (shiftset, shiftset, lookaheadset);
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}
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bitset_zero (shiftset);
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for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++)
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if (!SHIFT_IS_DISABLED (shiftp, i))
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bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
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for (i = 0; i < ntokens; i++)
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{
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int j;
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int defaulted = 0;
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int count = bitset_test (shiftset, i);
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for (j = 0; j < state->nlookaheads; ++j)
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if (bitset_test (state->lookaheads[j], i))
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{
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if (count == 0)
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{
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if (j != default_LA)
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fprintf (out,
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_(" %-4s\treduce using rule %d (%s)\n"),
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symbol_tag_get (symbols[i]),
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state->lookaheads_rule[j]->number - 1,
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symbol_tag_get_n (state->lookaheads_rule[j]->lhs, 1));
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else
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defaulted = 1;
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count++;
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}
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if (state->lookaheads_rule[j] != default_rule)
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fprintf (out,
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_(" %-4s\treduce using rule %d (%s)\n"),
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symbol_tag_get (symbols[i]),
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state->lookaheads_rule[j]->number - 1,
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symbol_tag_get_n (state->lookaheads_rule[j]->lhs, 1));
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else
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{
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if (defaulted)
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fprintf (out,
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_(" %-4s\treduce using rule %d (%s)\n"),
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symbol_tag_get (symbols[i]),
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state->lookaheads_rule[default_LA]->number - 1,
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symbol_tag_get_n (state->lookaheads_rule[default_LA]->lhs, 1));
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defaulted = 0;
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fprintf (out,
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_(" %-4s\t[reduce using rule %d (%s)]\n"),
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symbol_tag_get (symbols[i]),
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state->lookaheads_rule[j]->number - 1,
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symbol_tag_get_n (state->lookaheads_rule[j]->lhs, 1));
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}
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defaulted = 1;
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count++;
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}
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}
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if (default_LA >= 0)
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fprintf (out, _(" $default\treduce using rule %d (%s)\n"),
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default_rule->number - 1,
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symbol_tag_get (default_rule->lhs));
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else
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{
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if (defaulted)
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fprintf (out,
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_(" %-4s\treduce using rule %d (%s)\n"),
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symbol_tag_get (symbols[i]),
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default_rule->number - 1,
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symbol_tag_get_n (default_rule->lhs, 1));
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defaulted = 0;
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fprintf (out,
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_(" %-4s\t[reduce using rule %d (%s)]\n"),
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symbol_tag_get (symbols[i]),
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state->lookaheads_rule[j]->number - 1,
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symbol_tag_get_n (state->lookaheads_rule[j]->lhs, 1));
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}
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}
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}
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if (default_rule)
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fprintf (out, _(" $default\treduce using rule %d (%s)\n"),
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default_rule->number - 1,
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symbol_tag_get (default_rule->lhs));
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fputc ('\n', out);
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}
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/*--------------------------------------------------------------.
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| Report on OUT all the actions (shifts, gotos, reductions, and |
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| explicit erros from %nonassoc) of STATE. |
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`--------------------------------------------------------------*/
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static void
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print_actions (FILE *out, state_t *state)
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{
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@@ -306,9 +316,9 @@ print_actions (FILE *out, state_t *state)
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if (shiftp->nshifts == 0 && redp->nreds == 0)
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{
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if (state->number == final_state->number)
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fprintf (out, _(" $default\taccept\n"));
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fprintf (out, _(" $default\taccept\n"));
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else
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fprintf (out, _(" NO ACTIONS\n"));
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fprintf (out, _(" NO ACTIONS\n"));
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return;
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}
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@@ -318,6 +328,7 @@ print_actions (FILE *out, state_t *state)
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print_gotos (out, state);
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}
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static void
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print_state (FILE *out, state_t *state)
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{
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