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* src/conflicts.c (flush_shift): Also adjust lookaheadset.

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(flush_reduce): New.
(resolve_sr_conflict): Adjust.
This commit is contained in:
Akim Demaille
2001-12-17 17:32:08 +00:00
parent f87685c324
commit 709ae8c6ee
2 changed files with 52 additions and 47 deletions
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7
ChangeLog
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@@ -1,3 +1,10 @@
2001-12-17 Akim Demaille <akim@epita.fr>
* src/conflicts.c (flush_shift): Also adjust lookaheadset.
(flush_reduce): New.
(resolve_sr_conflict): Adjust.
2001-12-17 Akim Demaille <akim@epita.fr>
* src/output.c (output_obstack): Be static and rename as...

92
src/conflicts.c
View File

@@ -60,12 +60,26 @@ flush_shift (int state, int token)
shifts *shiftp = state_table[state]->shifts;
int i;
RESETBIT (lookaheadset, token);
for (i = 0; i < shiftp->nshifts; i++)
if (!SHIFT_IS_DISABLED (shiftp, i) && SHIFT_SYMBOL (shiftp, i) == token)
SHIFT_DISABLE (shiftp, i);
}
/*-------------------------------------------------------------------.
| Turn off the reduce recorded for the specified token for the |
| specified lookahead. Used when we resolve a shift-reduce conflict |
| in favor of the shift. |
`-------------------------------------------------------------------*/
static void
flush_reduce (int lookahead, int token)
{
RESETBIT (LA (lookahead), token);
}
/*------------------------------------------------------------------.
| Attempt to resolve shift-reduce conflict for one rule by means of |
| precedence declarations. It has already been checked that the |
@@ -74,74 +88,58 @@ flush_shift (int state, int token)
`------------------------------------------------------------------*/
static void
resolve_sr_conflict (int state, int lookaheadnum)
resolve_sr_conflict (int state, int lookahead)
{
int i;
/* find the rule to reduce by to get precedence of reduction */
int redprec = rule_table[LAruleno[lookaheadnum]].prec;
int redprec = rule_table[LAruleno[lookahead]].prec;
errs *errp = ERRS_ALLOC (ntokens + 1);
short *errtokens = errp->errs;
for (i = 0; i < ntokens; i++)
if (BITISSET (LA (lookaheadnum), i)
if (BITISSET (LA (lookahead), i)
&& BITISSET (lookaheadset, i)
&& sprec[i])
/* Shift-reduce conflict occurs for token number i
and it has a precedence.
The precedence of shifting is that of token i. */
{
/* Shift-reduce conflict occurs for token number i
and it has a precedence.
The precedence of shifting is that of token i. */
if (sprec[i] < redprec)
{
log_resolution (state, lookaheadnum, i, _("reduce"));
/* flush the shift for this token */
RESETBIT (lookaheadset, i);
log_resolution (state, lookahead, i, _("reduce"));
flush_shift (state, i);
}
else if (sprec[i] > redprec)
{
log_resolution (state, lookaheadnum, i, _("shift"));
/* flush the reduce for this token */
RESETBIT (LA (lookaheadnum), i);
log_resolution (state, lookahead, i, _("shift"));
flush_reduce (lookahead, i);
}
else
{
/* Matching precedence levels.
For left association, keep only the reduction.
For right association, keep only the shift.
For nonassociation, keep neither. */
/* Matching precedence levels.
For left association, keep only the reduction.
For right association, keep only the shift.
For nonassociation, keep neither. */
switch (sassoc[i])
{
case right_assoc:
log_resolution (state, lookaheadnum, i, _("shift"));
break;
switch (sassoc[i])
{
case right_assoc:
log_resolution (state, lookahead, i, _("shift"));
flush_reduce (lookahead, i);
break;
case left_assoc:
log_resolution (state, lookaheadnum, i, _("reduce"));
break;
case left_assoc:
log_resolution (state, lookahead, i, _("reduce"));
flush_shift (state, i);
break;
case non_assoc:
log_resolution (state, lookaheadnum, i, _("an error"));
break;
}
if (sassoc[i] != right_assoc)
{
/* flush the shift for this token */
RESETBIT (lookaheadset, i);
flush_shift (state, i);
}
if (sassoc[i] != left_assoc)
{
/* flush the reduce for this token */
RESETBIT (LA (lookaheadnum), i);
}
if (sassoc[i] == non_assoc)
{
/* Record an explicit error for this token. */
*errtokens++ = i;
}
}
case non_assoc:
log_resolution (state, lookahead, i, _("an error"));
flush_shift (state, i);
flush_reduce (lookahead, i);
/* Record an explicit error for this token. */
*errtokens++ = i;
break;
}
}
errp->nerrs = errtokens - errp->errs;