396 lines
8.1 KiB
C
396 lines
8.1 KiB
C
/*
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* Copyright (c) 1989 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Robert Paul Corbett.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)mkpar.c 5.3 (Berkeley) 1/20/91";
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#endif /* not lint */
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#include "defs.h"
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action **parser;
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int SRtotal;
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int RRtotal;
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short *SRconflicts;
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short *RRconflicts;
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short *defred;
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short *rules_used;
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short nunused;
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short final_state;
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static int SRcount;
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static int RRcount;
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extern action *parse_actions();
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extern action *get_shifts();
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extern action *add_reductions();
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extern action *add_reduce();
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make_parser()
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{
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register int i;
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parser = NEW2(nstates, action *);
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for (i = 0; i < nstates; i++)
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parser[i] = parse_actions(i);
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find_final_state();
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remove_conflicts();
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unused_rules();
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if (SRtotal + RRtotal > 0) total_conflicts();
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defreds();
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}
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action *
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parse_actions(stateno)
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register int stateno;
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{
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register action *actions;
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actions = get_shifts(stateno);
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actions = add_reductions(stateno, actions);
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return (actions);
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}
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action *
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get_shifts(stateno)
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int stateno;
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{
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register action *actions, *temp;
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register shifts *sp;
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register short *to_state;
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register int i, k;
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register int symbol;
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actions = 0;
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sp = shift_table[stateno];
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if (sp)
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{
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to_state = sp->shift;
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for (i = sp->nshifts - 1; i >= 0; i--)
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{
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k = to_state[i];
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symbol = accessing_symbol[k];
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if (ISTOKEN(symbol))
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{
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temp = NEW(action);
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temp->next = actions;
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temp->symbol = symbol;
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temp->number = k;
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temp->prec = symbol_prec[symbol];
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temp->action_code = SHIFT;
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temp->assoc = symbol_assoc[symbol];
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actions = temp;
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}
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}
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}
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return (actions);
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}
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action *
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add_reductions(stateno, actions)
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int stateno;
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register action *actions;
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{
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register int i, j, m, n;
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register int ruleno, tokensetsize;
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register unsigned *rowp;
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tokensetsize = WORDSIZE(ntokens);
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m = lookaheads[stateno];
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n = lookaheads[stateno + 1];
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for (i = m; i < n; i++)
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{
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ruleno = LAruleno[i];
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rowp = LA + i * tokensetsize;
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for (j = ntokens - 1; j >= 0; j--)
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{
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if (BIT(rowp, j))
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actions = add_reduce(actions, ruleno, j);
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}
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}
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return (actions);
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}
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action *
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add_reduce(actions, ruleno, symbol)
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register action *actions;
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register int ruleno, symbol;
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{
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register action *temp, *prev, *next;
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prev = 0;
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for (next = actions; next && next->symbol < symbol; next = next->next)
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prev = next;
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while (next && next->symbol == symbol && next->action_code == SHIFT)
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{
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prev = next;
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next = next->next;
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}
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while (next && next->symbol == symbol &&
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next->action_code == REDUCE && next->number < ruleno)
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{
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prev = next;
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next = next->next;
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}
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temp = NEW(action);
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temp->next = next;
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temp->symbol = symbol;
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temp->number = ruleno;
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temp->prec = rprec[ruleno];
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temp->action_code = REDUCE;
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temp->assoc = rassoc[ruleno];
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if (prev)
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prev->next = temp;
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else
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actions = temp;
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return (actions);
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}
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find_final_state()
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{
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register int goal, i;
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register short *to_state;
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register shifts *p;
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p = shift_table[0];
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to_state = p->shift;
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goal = ritem[1];
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for (i = p->nshifts - 1; i >= 0; --i)
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{
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final_state = to_state[i];
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if (accessing_symbol[final_state] == goal) break;
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}
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}
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unused_rules()
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{
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register int i;
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register action *p;
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rules_used = (short *) MALLOC(nrules*sizeof(short));
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if (rules_used == 0) no_space();
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for (i = 0; i < nrules; ++i)
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rules_used[i] = 0;
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for (i = 0; i < nstates; ++i)
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{
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for (p = parser[i]; p; p = p->next)
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{
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if (p->action_code == REDUCE && p->suppressed == 0)
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rules_used[p->number] = 1;
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}
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}
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nunused = 0;
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for (i = 3; i < nrules; ++i)
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if (!rules_used[i]) ++nunused;
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if (nunused)
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if (nunused == 1)
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fprintf(stderr, "%s: 1 rule never reduced\n", myname);
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else
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fprintf(stderr, "%s: %d rules never reduced\n", myname, nunused);
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}
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remove_conflicts()
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{
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register int i;
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register int symbol;
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register action *p, *pref;
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SRtotal = 0;
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RRtotal = 0;
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SRconflicts = NEW2(nstates, short);
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RRconflicts = NEW2(nstates, short);
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for (i = 0; i < nstates; i++)
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{
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SRcount = 0;
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RRcount = 0;
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symbol = -1;
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for (p = parser[i]; p; p = p->next)
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{
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if (p->symbol != symbol)
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{
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pref = p;
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symbol = p->symbol;
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}
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else if (i == final_state && symbol == 0)
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{
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SRcount++;
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p->suppressed = 1;
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}
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else if (pref->action_code == SHIFT)
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{
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if (pref->prec > 0 && p->prec > 0)
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{
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if (pref->prec < p->prec)
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{
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pref->suppressed = 2;
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pref = p;
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}
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else if (pref->prec > p->prec)
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{
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p->suppressed = 2;
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}
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else if (pref->assoc == LEFT)
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{
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pref->suppressed = 2;
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pref = p;
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}
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else if (pref->assoc == RIGHT)
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{
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p->suppressed = 2;
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}
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else
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{
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pref->suppressed = 2;
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p->suppressed = 2;
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}
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}
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else
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{
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SRcount++;
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p->suppressed = 1;
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}
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}
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else
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{
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RRcount++;
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p->suppressed = 1;
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}
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}
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SRtotal += SRcount;
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RRtotal += RRcount;
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SRconflicts[i] = SRcount;
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RRconflicts[i] = RRcount;
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}
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}
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total_conflicts()
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{
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fprintf(stderr, "%s: ", myname);
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if (SRtotal == 1)
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fprintf(stderr, "1 shift/reduce conflict");
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else if (SRtotal > 1)
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fprintf(stderr, "%d shift/reduce conflicts", SRtotal);
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if (SRtotal && RRtotal)
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fprintf(stderr, ", ");
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if (RRtotal == 1)
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fprintf(stderr, "1 reduce/reduce conflict");
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else if (RRtotal > 1)
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fprintf(stderr, "%d reduce/reduce conflicts", RRtotal);
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fprintf(stderr, ".\n");
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}
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int
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sole_reduction(stateno)
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int stateno;
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{
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register int count, ruleno;
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register action *p;
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count = 0;
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ruleno = 0;
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for (p = parser[stateno]; p; p = p->next)
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{
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if (p->action_code == SHIFT && p->suppressed == 0)
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return (0);
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else if (p->action_code == REDUCE && p->suppressed == 0)
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{
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if (ruleno > 0 && p->number != ruleno)
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return (0);
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if (p->symbol != 1)
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++count;
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ruleno = p->number;
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}
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}
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if (count == 0)
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return (0);
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return (ruleno);
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}
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defreds()
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{
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register int i;
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defred = NEW2(nstates, short);
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for (i = 0; i < nstates; i++)
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defred[i] = sole_reduction(i);
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}
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free_action_row(p)
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register action *p;
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{
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register action *q;
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while (p)
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{
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q = p->next;
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FREE(p);
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p = q;
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}
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}
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free_parser()
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{
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register int i;
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for (i = 0; i < nstates; i++)
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free_action_row(parser[i]);
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FREE(parser);
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}
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