src/lalr.c

/* Compute look-ahead criteria for bison,
   Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002
   Free Software Foundation, Inc.

   This file is part of Bison, the GNU Compiler Compiler.

   Bison is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   Bison is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Bison; see the file COPYING.  If not, write to
   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */


/* Compute how to make the finite state machine deterministic; find
   which rules need lookahead in each state, and which lookahead
   tokens they accept.  */

#include "system.h"
#include "bitset.h"
#include "bitsetv.h"
#include "relation.h"
#include "quotearg.h"
#include "symtab.h"
#include "gram.h"
#include "reader.h"
#include "types.h"
#include "LR0.h"
#include "complain.h"
#include "lalr.h"
#include "nullable.h"
#include "derives.h"
#include "getargs.h"

rule_t **LArule = NULL;
bitsetv LA = NULL;
size_t nLA;

static int ngotos;
short *goto_map = NULL;
state_number_t *from_state = NULL;
state_number_t *to_state = NULL;

/* And for the famous F variable, which name is so descriptive that a
   comment is hardly needed.  <grin>.  */
static bitsetv F = NULL;

static short **includes;
static shorts **lookback;


static void
initialize_LA (void)
{
  state_number_t i;
  int j;
  rule_t **np;

  /* Avoid having to special case 0.  */
  if (!nLA)
    nLA = 1;

  LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
  LArule = XCALLOC (rule_t *, nLA);
  lookback = XCALLOC (shorts *, nLA);

  np = LArule;
  for (i = 0; i < nstates; i++)
    if (!states[i]->consistent)
      for (j = 0; j < states[i]->reductions->num; j++)
	*np++ = &rules[states[i]->reductions->rules[j]];
}


static void
set_goto_map (void)
{
  state_number_t state;
  short *temp_map;

  goto_map = XCALLOC (short, nvars + 1) - ntokens;
  temp_map = XCALLOC (short, nvars + 1) - ntokens;

  ngotos = 0;
  for (state = 0; state < nstates; ++state)
    {
      transitions_t *sp = states[state]->shifts;
      int i;
      for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
	{
	  if (ngotos == SHRT_MAX)
	    fatal (_("too many gotos (max %d)"), SHRT_MAX);

	  ngotos++;
	  goto_map[TRANSITION_SYMBOL (sp, i)]++;
	}
    }

  {
    int k = 0;
    int i;
    for (i = ntokens; i < nsyms; i++)
      {
	temp_map[i] = k;
	k += goto_map[i];
      }

    for (i = ntokens; i < nsyms; i++)
      goto_map[i] = temp_map[i];

    goto_map[nsyms] = ngotos;
    temp_map[nsyms] = ngotos;
  }

  from_state = XCALLOC (state_number_t, ngotos);
  to_state = XCALLOC (state_number_t, ngotos);

  for (state = 0; state < nstates; ++state)
    {
      transitions_t *sp = states[state]->shifts;
      int i;
      for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
	{
	  int k = temp_map[TRANSITION_SYMBOL (sp, i)]++;
	  from_state[k] = state;
	  to_state[k] = sp->states[i];
	}
    }

  XFREE (temp_map + ntokens);
}


/*----------------------------------------------------------.
| Map a state/symbol pair into its numeric representation.  |
`----------------------------------------------------------*/

static int
map_goto (state_number_t state, symbol_number_t symbol)
{
  int high;
  int low;
  int middle;
  state_number_t s;

  low = goto_map[symbol];
  high = goto_map[symbol + 1] - 1;

  while (low <= high)
    {
      middle = (low + high) / 2;
      s = from_state[middle];
      if (s == state)
	return middle;
      else if (s < state)
	low = middle + 1;
      else
	high = middle - 1;
    }

  assert (0);
  /* NOTREACHED */
  return 0;
}


static void
initialize_F (void)
{
  short **reads = XCALLOC (short *, ngotos);
  short *edge = XCALLOC (short, ngotos + 1);
  int nedges = 0;

  int i;

  F = bitsetv_create (ngotos, ntokens, BITSET_FIXED);

  for (i = 0; i < ngotos; i++)
    {
      state_number_t stateno = to_state[i];
      transitions_t *sp = states[stateno]->shifts;

      int j;
      for (j = 0; j < sp->num && TRANSITION_IS_SHIFT (sp, j); j++)
	bitset_set (F[i], TRANSITION_SYMBOL (sp, j));

      for (; j < sp->num; j++)
	{
	  symbol_number_t symbol = TRANSITION_SYMBOL (sp, j);
	  if (nullable[symbol])
	    edge[nedges++] = map_goto (stateno, symbol);
	}

      if (nedges)
	{
	  reads[i] = XCALLOC (short, nedges + 1);
	  memcpy (reads[i], edge, nedges * sizeof (edge[0]));
	  reads[i][nedges] = -1;
	  nedges = 0;
	}
    }

  relation_digraph (reads, ngotos, &F);

  for (i = 0; i < ngotos; i++)
    XFREE (reads[i]);

  XFREE (reads);
  XFREE (edge);
}


static void
add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono)
{
  int i;
  shorts *sp;

  for (i = 0; i < state->nlookaheads; ++i)
    if (state->lookaheads_rule[i]->number == ruleno)
      break;

  assert (state->lookaheads_rule[i]->number == ruleno);

  sp = XCALLOC (shorts, 1);
  sp->next = lookback[(state->lookaheads - LA) + i];
  sp->value = gotono;
  lookback[(state->lookaheads - LA) + i] = sp;
}


static void
build_relations (void)
{
  short *edge = XCALLOC (short, ngotos + 1);
  state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1);
  int i;

  includes = XCALLOC (short *, ngotos);

  for (i = 0; i < ngotos; i++)
    {
      int nedges = 0;
      symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;
      rule_number_t *rulep;

      for (rulep = derives[symbol1]; *rulep > 0; rulep++)
	{
	  int done;
	  int length = 1;
	  item_number_t *rp;
	  state_t *state = states[from_state[i]];
	  states1[0] = state->number;

	  for (rp = rules[*rulep].rhs; *rp >= 0; rp++)
	    {
	      state = transitions_to (state->shifts,
				 item_number_as_symbol_number (*rp));
	      states1[length++] = state->number;
	    }

	  if (!state->consistent)
	    add_lookback_edge (state, *rulep, i);

	  length--;
	  done = 0;
	  while (!done)
	    {
	      done = 1;
	      rp--;
	      /* JF added rp>=ritem &&   I hope to god its right! */
	      if (rp >= ritem && ISVAR (*rp))
		{
		  /* Downcasting from item_number_t to symbol_number_t. */
		  edge[nedges++] = map_goto (states1[--length],
					     item_number_as_symbol_number (*rp));
		  if (nullable[*rp])
		    done = 0;
		}
	    }
	}

      if (nedges)
	{
	  int j;
	  includes[i] = XCALLOC (short, nedges + 1);
	  for (j = 0; j < nedges; j++)
	    includes[i][j] = edge[j];
	  includes[i][nedges] = -1;
	}
    }

  XFREE (edge);
  XFREE (states1);

  relation_transpose (&includes, ngotos);
}


static void
compute_FOLLOWS (void)
{
  int i;

  relation_digraph (includes, ngotos, &F);

  for (i = 0; i < ngotos; i++)
    XFREE (includes[i]);

  XFREE (includes);
}


static void
compute_lookaheads (void)
{
  size_t i;
  shorts *sp;

  for (i = 0; i < nLA; i++)
    for (sp = lookback[i]; sp; sp = sp->next)
      bitset_or (LA[i], LA[i], F[sp->value]);

  /* Free LOOKBACK. */
  for (i = 0; i < nLA; i++)
    LIST_FREE (shorts, lookback[i]);

  XFREE (lookback);
  bitsetv_free (F);
}


/*-------------------------------------------------------------.
| Count the number of lookaheads required for each state       |
| (NLOOKAHEADS member).  Compute the total number of LA, NLA.  |
`-------------------------------------------------------------*/

static void
states_lookaheads_count (void)
{
  state_number_t i;
  nLA = 0;

  /* Count   */
  for (i = 0; i < nstates; i++)
    {
      int k;
      int nlookaheads = 0;
      reductions_t *rp = states[i]->reductions;
      transitions_t *sp = states[i]->shifts;

      /* We need a lookahead either to distinguish different
	 reductions (i.e., there are two or more), or to distinguish a
	 reduction from a shift.  Otherwise, it is straightforward,
	 and the state is `consistent'.  */
      if (rp->num > 1
	  || (rp->num == 1 && sp->num && TRANSITION_IS_SHIFT (sp, 0)))
	nlookaheads += rp->num;
      else
	states[i]->consistent = 1;

      for (k = 0; k < sp->num; k++)
	if (TRANSITION_IS_ERROR (sp, k))
	  {
	    states[i]->consistent = 0;
	    break;
	  }

      states[i]->nlookaheads = nlookaheads;
      nLA += nlookaheads;
    }
}


/*--------------------------------------.
| Initializing the lookaheads members.  |
`--------------------------------------*/

static void
states_lookaheads_initialize (void)
{
  state_number_t i;
  bitsetv pLA = LA;
  rule_t **pLArule = LArule;

  /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
     state.  */
  for (i = 0; i < nstates; i++)
    {
      states[i]->lookaheads = pLA;
      states[i]->lookaheads_rule = pLArule;
      pLA += states[i]->nlookaheads;
      pLArule += states[i]->nlookaheads;
    }
}


/*---------------------------------------.
| Output the lookaheads for each state.  |
`---------------------------------------*/

static void
lookaheads_print (FILE *out)
{
  state_number_t i;
  int j, k;
  fprintf (out, "Lookaheads: BEGIN\n");
  for (i = 0; i < nstates; ++i)
    {
      fprintf (out, "State %d: %d lookaheads\n",
	       i, states[i]->nlookaheads);

      for (j = 0; j < states[i]->nlookaheads; ++j)
	BITSET_EXECUTE (states[i]->lookaheads[j], 0, k,
	{
	  fprintf (out, "   on %d (%s) -> rule %d\n",
		   k, symbols[k]->tag,
		   states[i]->lookaheads_rule[j]->number - 1);
	});
    }
  fprintf (out, "Lookaheads: END\n");
}

void
lalr (void)
{
  states_lookaheads_count ();
  initialize_LA ();
  states_lookaheads_initialize ();
  set_goto_map ();
  initialize_F ();
  build_relations ();
  compute_FOLLOWS ();
  compute_lookaheads ();

  if (trace_flag)
    lookaheads_print (stderr);
}
Commit	Line	Data
	1	/* Compute look-ahead criteria for bison,
	2	Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002
	3	Free Software Foundation, Inc.
	4
	5	This file is part of Bison, the GNU Compiler Compiler.
	6
	7	Bison is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 2, or (at your option)
	10	any later version.
	11
	12	Bison is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with Bison; see the file COPYING. If not, write to
	19	the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	20	Boston, MA 02111-1307, USA. */
	21
	22
	23	/* Compute how to make the finite state machine deterministic; find
	24	which rules need lookahead in each state, and which lookahead
	25	tokens they accept. */
	26
	27	#include "system.h"
	28	#include "bitset.h"
	29	#include "bitsetv.h"
	30	#include "relation.h"
	31	#include "quotearg.h"
	32	#include "symtab.h"
	33	#include "gram.h"
	34	#include "reader.h"
	35	#include "types.h"
	36	#include "LR0.h"
	37	#include "complain.h"
	38	#include "lalr.h"
	39	#include "nullable.h"
	40	#include "derives.h"
	41	#include "getargs.h"
	42
	43	rule_t **LArule = NULL;
	44	bitsetv LA = NULL;
	45	size_t nLA;
	46
	47	static int ngotos;
	48	short *goto_map = NULL;
	49	state_number_t *from_state = NULL;
	50	state_number_t *to_state = NULL;
	51
	52	/* And for the famous F variable, which name is so descriptive that a
	53	comment is hardly needed. <grin>. */
	54	static bitsetv F = NULL;
	55
	56	static short **includes;
	57	static shorts **lookback;
	58
	59
	60
	61
	62	static void
	63	initialize_LA (void)
	64	{
	65	state_number_t i;
	66	int j;
	67	rule_t **np;
	68
	69	/* Avoid having to special case 0. */
	70	if (!nLA)
	71	nLA = 1;
	72
	73	LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
	74	LArule = XCALLOC (rule_t *, nLA);
	75	lookback = XCALLOC (shorts *, nLA);
	76
	77	np = LArule;
	78	for (i = 0; i < nstates; i++)
	79	if (!states[i]->consistent)
	80	for (j = 0; j < states[i]->reductions->num; j++)
	81	*np++ = &rules[states[i]->reductions->rules[j]];
	82	}
	83
	84
	85	static void
	86	set_goto_map (void)
	87	{
	88	state_number_t state;
	89	short *temp_map;
	90
	91	goto_map = XCALLOC (short, nvars + 1) - ntokens;
	92	temp_map = XCALLOC (short, nvars + 1) - ntokens;
	93
	94	ngotos = 0;
	95	for (state = 0; state < nstates; ++state)
	96	{
	97	transitions_t *sp = states[state]->shifts;
	98	int i;
	99	for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
	100	{
	101	if (ngotos == SHRT_MAX)
	102	fatal (_("too many gotos (max %d)"), SHRT_MAX);
	103
	104	ngotos++;
	105	goto_map[TRANSITION_SYMBOL (sp, i)]++;
	106	}
	107	}
	108
	109	{
	110	int k = 0;
	111	int i;
	112	for (i = ntokens; i < nsyms; i++)
	113	{
	114	temp_map[i] = k;
	115	k += goto_map[i];
	116	}
	117
	118	for (i = ntokens; i < nsyms; i++)
	119	goto_map[i] = temp_map[i];
	120
	121	goto_map[nsyms] = ngotos;
	122	temp_map[nsyms] = ngotos;
	123	}
	124
	125	from_state = XCALLOC (state_number_t, ngotos);
	126	to_state = XCALLOC (state_number_t, ngotos);
	127
	128	for (state = 0; state < nstates; ++state)
	129	{
	130	transitions_t *sp = states[state]->shifts;
	131	int i;
	132	for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
	133	{
	134	int k = temp_map[TRANSITION_SYMBOL (sp, i)]++;
	135	from_state[k] = state;
	136	to_state[k] = sp->states[i];
	137	}
	138	}
	139
	140	XFREE (temp_map + ntokens);
	141	}
	142
	143
	144
	145	/*----------------------------------------------------------.
	146	\| Map a state/symbol pair into its numeric representation. \|
	147	`----------------------------------------------------------*/
	148
	149	static int
	150	map_goto (state_number_t state, symbol_number_t symbol)
	151	{
	152	int high;
	153	int low;
	154	int middle;
	155	state_number_t s;
	156
	157	low = goto_map[symbol];
	158	high = goto_map[symbol + 1] - 1;
	159
	160	while (low <= high)
	161	{
	162	middle = (low + high) / 2;
	163	s = from_state[middle];
	164	if (s == state)
	165	return middle;
	166	else if (s < state)
	167	low = middle + 1;
	168	else
	169	high = middle - 1;
	170	}
	171
	172	assert (0);
	173	/* NOTREACHED */
	174	return 0;
	175	}
	176
	177
	178	static void
	179	initialize_F (void)
	180	{
	181	short *reads = XCALLOC (short , ngotos);
	182	short *edge = XCALLOC (short, ngotos + 1);
	183	int nedges = 0;
	184
	185	int i;
	186
	187	F = bitsetv_create (ngotos, ntokens, BITSET_FIXED);
	188
	189	for (i = 0; i < ngotos; i++)
	190	{
	191	state_number_t stateno = to_state[i];
	192	transitions_t *sp = states[stateno]->shifts;
	193
	194	int j;
	195	for (j = 0; j < sp->num && TRANSITION_IS_SHIFT (sp, j); j++)
	196	bitset_set (F[i], TRANSITION_SYMBOL (sp, j));
	197
	198	for (; j < sp->num; j++)
	199	{
	200	symbol_number_t symbol = TRANSITION_SYMBOL (sp, j);
	201	if (nullable[symbol])
	202	edge[nedges++] = map_goto (stateno, symbol);
	203	}
	204
	205	if (nedges)
	206	{
	207	reads[i] = XCALLOC (short, nedges + 1);
	208	memcpy (reads[i], edge, nedges * sizeof (edge[0]));
	209	reads[i][nedges] = -1;
	210	nedges = 0;
	211	}
	212	}
	213
	214	relation_digraph (reads, ngotos, &F);
	215
	216	for (i = 0; i < ngotos; i++)
	217	XFREE (reads[i]);
	218
	219	XFREE (reads);
	220	XFREE (edge);
	221	}
	222
	223
	224	static void
	225	add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono)
	226	{
	227	int i;
	228	shorts *sp;
	229
	230	for (i = 0; i < state->nlookaheads; ++i)
	231	if (state->lookaheads_rule[i]->number == ruleno)
	232	break;
	233
	234	assert (state->lookaheads_rule[i]->number == ruleno);
	235
	236	sp = XCALLOC (shorts, 1);
	237	sp->next = lookback[(state->lookaheads - LA) + i];
	238	sp->value = gotono;
	239	lookback[(state->lookaheads - LA) + i] = sp;
	240	}
	241
	242
	243
	244	static void
	245	build_relations (void)
	246	{
	247	short *edge = XCALLOC (short, ngotos + 1);
	248	state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1);
	249	int i;
	250
	251	includes = XCALLOC (short *, ngotos);
	252
	253	for (i = 0; i < ngotos; i++)
	254	{
	255	int nedges = 0;
	256	symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;
	257	rule_number_t *rulep;
	258
	259	for (rulep = derives[symbol1]; *rulep > 0; rulep++)
	260	{
	261	int done;
	262	int length = 1;
	263	item_number_t *rp;
	264	state_t *state = states[from_state[i]];
	265	states1[0] = state->number;
	266
	267	for (rp = rules[rulep].rhs; rp >= 0; rp++)
	268	{
	269	state = transitions_to (state->shifts,
	270	item_number_as_symbol_number (*rp));
	271	states1[length++] = state->number;
	272	}
	273
	274	if (!state->consistent)
	275	add_lookback_edge (state, *rulep, i);
	276
	277	length--;
	278	done = 0;
	279	while (!done)
	280	{
	281	done = 1;
	282	rp--;
	283	/* JF added rp>=ritem && I hope to god its right! */
	284	if (rp >= ritem && ISVAR (*rp))
	285	{
	286	/* Downcasting from item_number_t to symbol_number_t. */
	287	edge[nedges++] = map_goto (states1[--length],
	288	item_number_as_symbol_number (*rp));
	289	if (nullable[*rp])
	290	done = 0;
	291	}
	292	}
	293	}
	294
	295	if (nedges)
	296	{
	297	int j;
	298	includes[i] = XCALLOC (short, nedges + 1);
	299	for (j = 0; j < nedges; j++)
	300	includes[i][j] = edge[j];
	301	includes[i][nedges] = -1;
	302	}
	303	}
	304
	305	XFREE (edge);
	306	XFREE (states1);
	307
	308	relation_transpose (&includes, ngotos);
	309	}
	310
	311
	312
	313	static void
	314	compute_FOLLOWS (void)
	315	{
	316	int i;
	317
	318	relation_digraph (includes, ngotos, &F);
	319
	320	for (i = 0; i < ngotos; i++)
	321	XFREE (includes[i]);
	322
	323	XFREE (includes);
	324	}
	325
	326
	327	static void
	328	compute_lookaheads (void)
	329	{
	330	size_t i;
	331	shorts *sp;
	332
	333	for (i = 0; i < nLA; i++)
	334	for (sp = lookback[i]; sp; sp = sp->next)
	335	bitset_or (LA[i], LA[i], F[sp->value]);
	336
	337	/* Free LOOKBACK. */
	338	for (i = 0; i < nLA; i++)
	339	LIST_FREE (shorts, lookback[i]);
	340
	341	XFREE (lookback);
	342	bitsetv_free (F);
	343	}
	344
	345
	346	/*-------------------------------------------------------------.
	347	\| Count the number of lookaheads required for each state \|
	348	\| (NLOOKAHEADS member). Compute the total number of LA, NLA. \|
	349	`-------------------------------------------------------------*/
	350
	351	static void
	352	states_lookaheads_count (void)
	353	{
	354	state_number_t i;
	355	nLA = 0;
	356
	357	/* Count */
	358	for (i = 0; i < nstates; i++)
	359	{
	360	int k;
	361	int nlookaheads = 0;
	362	reductions_t *rp = states[i]->reductions;
	363	transitions_t *sp = states[i]->shifts;
	364
	365	/* We need a lookahead either to distinguish different
	366	reductions (i.e., there are two or more), or to distinguish a
	367	reduction from a shift. Otherwise, it is straightforward,
	368	and the state is `consistent'. */
	369	if (rp->num > 1
	370	\|\| (rp->num == 1 && sp->num && TRANSITION_IS_SHIFT (sp, 0)))
	371	nlookaheads += rp->num;
	372	else
	373	states[i]->consistent = 1;
	374
	375	for (k = 0; k < sp->num; k++)
	376	if (TRANSITION_IS_ERROR (sp, k))
	377	{
	378	states[i]->consistent = 0;
	379	break;
	380	}
	381
	382	states[i]->nlookaheads = nlookaheads;
	383	nLA += nlookaheads;
	384	}
	385	}
	386
	387
	388	/*--------------------------------------.
	389	\| Initializing the lookaheads members. \|
	390	`--------------------------------------*/
	391
	392	static void
	393	states_lookaheads_initialize (void)
	394	{
	395	state_number_t i;
	396	bitsetv pLA = LA;
	397	rule_t **pLArule = LArule;
	398
	399	/* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
	400	state. */
	401	for (i = 0; i < nstates; i++)
	402	{
	403	states[i]->lookaheads = pLA;
	404	states[i]->lookaheads_rule = pLArule;
	405	pLA += states[i]->nlookaheads;
	406	pLArule += states[i]->nlookaheads;
	407	}
	408	}
	409
	410
	411	/*---------------------------------------.
	412	\| Output the lookaheads for each state. \|
	413	`---------------------------------------*/
	414
	415	static void
	416	lookaheads_print (FILE *out)
	417	{
	418	state_number_t i;
	419	int j, k;
	420	fprintf (out, "Lookaheads: BEGIN\n");
	421	for (i = 0; i < nstates; ++i)
	422	{
	423	fprintf (out, "State %d: %d lookaheads\n",
	424	i, states[i]->nlookaheads);
	425
	426	for (j = 0; j < states[i]->nlookaheads; ++j)
	427	BITSET_EXECUTE (states[i]->lookaheads[j], 0, k,
	428	{
	429	fprintf (out, " on %d (%s) -> rule %d\n",
	430	k, symbols[k]->tag,
	431	states[i]->lookaheads_rule[j]->number - 1);
	432	});
	433	}
	434	fprintf (out, "Lookaheads: END\n");
	435	}
	436
	437	void
	438	lalr (void)
	439	{
	440	states_lookaheads_count ();
	441	initialize_LA ();
	442	states_lookaheads_initialize ();
	443	set_goto_map ();
	444	initialize_F ();
	445	build_relations ();
	446	compute_FOLLOWS ();
	447	compute_lookaheads ();
	448
	449	if (trace_flag)
	450	lookaheads_print (stderr);
	451	}