* src/LR0.c (new_state): Set it to 0.
* src/conflicts.h, src/conflicts.c (print_conflicts)
(free_conflicts, solve_conflicts): Rename as...
(conflicts_print, conflicts_free, conflicts_solve): these.
Adjust callers.
* src/conflicts.c (enum conflict_resolution_e)
(solved_conflicts_obstack): New, used by...
(log_resolution): this.
Adjust to attach the conflict resolution to each state.
Complete the description with the precedence/associativity
information.
(resolve_sr_conflict): Adjust.
* src/print.c (print_state): Output its solved_conflicts.
* tests/conflicts.at (Unresolved SR Conflicts)
(Solved SR Conflicts): Exercise --report=all.
+2002-05-26 Akim Demaille <akim@epita.fr>
+
+ * src/state.h (state_t): `solved_conflicts' is a new member.
+ * src/LR0.c (new_state): Set it to 0.
+ * src/conflicts.h, src/conflicts.c (print_conflicts)
+ (free_conflicts, solve_conflicts): Rename as...
+ (conflicts_print, conflicts_free, conflicts_solve): these.
+ Adjust callers.
+ * src/conflicts.c (enum conflict_resolution_e)
+ (solved_conflicts_obstack): New, used by...
+ (log_resolution): this.
+ Adjust to attach the conflict resolution to each state.
+ Complete the description with the precedence/associativity
+ information.
+ (resolve_sr_conflict): Adjust.
+ * src/print.c (print_state): Output its solved_conflicts.
+ * tests/conflicts.at (Unresolved SR Conflicts)
+ (Solved SR Conflicts): Exercise --report=all.
+
2002-05-26 Akim Demaille <akim@epita.fr>
* src/LR0.c, src/derives.c, src/gram.c, src/gram.h, src/lalr.c,
* Semantic parser
This old option, which has been broken for ages, is removed.
-* New translations
+* New translation
Croatian, thanks to Denis Lackovic.
* Incorrect token definitions
* Reports
In addition to --verbose, bison supports --report=THINGS, which
produces additional information:
-
- `itemset' complete the core item sets with their closure
- `lookahead' explicitly associate lookaheads to items
+ - itemset
+ complete the core item sets with their closure
+ - lookahead
+ explicitly associate lookaheads to items
+ - solved
+ describe shift/reduce conflicts solving.
+ Bison used to systematically output this information on top of
+ the report. Solved conflicts are now attached to their states.
\f
Changes in version 1.35, 2002-03-25:
Provide better assistance for understanding the conflicts by providing
a sample text exhibiting the (LALR) ambiguity.
-* report
-Solved conflicts should not be reported in the beginning of the file.
-Rather they should be reported within each state description. Also,
-now that the symbol providing the precedence of a rule is kept, it is
-possible to explain why a conflict was solved this way. E.g., instead
-of
-
- Conflict in state 8 between rule 2 and token '+' resolved as reduce.
-
-we can (in state 8) report something like
-
- Conflict between rule 2 and token '+' resolved as reduce
- because '*' < '+'.
-
-or something like that.
-
* Coding system independence
Paul notes:
p = STATE_ALLOC (core_size);
p->accessing_symbol = symbol;
p->number = nstates;
- p->nitems = core_size;
+ p->solved_conflicts = NULL;
+ p->nitems = core_size;
memcpy (p->items, core, core_size * sizeof (core[0]));
/* If this is the eoftoken, and this is not the initial state, then
/* -1 stands for not specified. */
int expected_conflicts = -1;
static char *conflicts = NULL;
+struct obstack solved_conflicts_obstack;
static bitset shiftset;
static bitset lookaheadset;
+
\f
+enum conflict_resolution_e
+ {
+ shift_resolution,
+ reduce_resolution,
+ left_resolution,
+ right_resolution,
+ nonassoc_resolution,
+ };
+
+
static inline void
-log_resolution (state_t *state, int LAno, int token, const char *resolution)
+log_resolution (int lookahead, int token,
+ enum conflict_resolution_e resolution)
{
- if (report_flag & report_states)
- obstack_fgrow4 (&output_obstack,
- _("\
-Conflict in state %d between rule %d and token %s resolved as %s.\n"),
- state->number,
- LArule[LAno]->number,
- symbols[token]->tag,
- resolution);
+ if (report_flag & report_solved_conflicts)
+ {
+ /* The description of the resolution. */
+ switch (resolution)
+ {
+ case shift_resolution:
+ case left_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ _("\
+ Conflict between rule %d and token %s resolved as shift"),
+ LArule[lookahead]->number,
+ symbols[token]->tag);
+ break;
+ case reduce_resolution:
+ case right_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ _("\
+ Conflict between rule %d and token %s resolved as reduce"),
+ LArule[lookahead]->number,
+ symbols[token]->tag);
+ break;
+ case nonassoc_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ _("\
+ Conflict between rule %d and token %s resolved as an error"),
+ LArule[lookahead]->number,
+ symbols[token]->tag);
+ break;
+ }
+
+ /* The reason. */
+ switch (resolution)
+ {
+ case shift_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ " (%s < %s)",
+ LArule[lookahead]->prec->tag,
+ symbols[token]->tag);
+ break;
+
+ case reduce_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ " (%s < %s)",
+ symbols[token]->tag,
+ LArule[lookahead]->prec->tag);
+ break;
+
+ case left_resolution:
+ obstack_printf (&solved_conflicts_obstack,
+ " (%%left %s)",
+ symbols[token]->tag);
+ break;
+
+ case right_resolution:
+ obstack_fgrow1 (&solved_conflicts_obstack,
+ " (%%right %s)",
+ symbols[token]->tag);
+ break;
+ case nonassoc_resolution:
+ obstack_fgrow1 (&solved_conflicts_obstack,
+ " (%%nonassoc %s)",
+ symbols[token]->tag);
+ break;
+ }
+ obstack_sgrow (&solved_conflicts_obstack, ".\n");
+ }
}
The precedence of shifting is that of token i. */
if (symbols[i]->prec < redprec)
{
- log_resolution (state, lookahead, i, _("reduce"));
+ log_resolution (lookahead, i, reduce_resolution);
flush_shift (state, i);
}
else if (symbols[i]->prec > redprec)
{
- log_resolution (state, lookahead, i, _("shift"));
+ log_resolution (lookahead, i, shift_resolution);
flush_reduce (lookahead, i);
}
else
switch (symbols[i]->assoc)
{
case right_assoc:
- log_resolution (state, lookahead, i, _("shift"));
+ log_resolution (lookahead, i, right_resolution);
flush_reduce (lookahead, i);
break;
case left_assoc:
- log_resolution (state, lookahead, i, _("reduce"));
+ log_resolution (lookahead, i, left_resolution);
flush_shift (state, i);
break;
case non_assoc:
- log_resolution (state, lookahead, i, _("an error"));
+ log_resolution (lookahead, i, nonassoc_resolution);
flush_shift (state, i);
flush_reduce (lookahead, i);
/* Record an explicit error for this token. */
permanent errs structure for this state, to record them. */
state->errs = errs_dup (errp);
free (errp);
+
+ if (obstack_object_size (&solved_conflicts_obstack))
+ {
+ obstack_1grow (&solved_conflicts_obstack, '\0');
+ state->solved_conflicts = obstack_finish (&solved_conflicts_obstack);
+ }
}
}
void
-solve_conflicts (void)
+conflicts_solve (void)
{
size_t i;
conflicts = XCALLOC (char, nstates);
shiftset = bitset_create (ntokens, BITSET_FIXED);
lookaheadset = bitset_create (ntokens, BITSET_FIXED);
+ obstack_init (&solved_conflicts_obstack);
for (i = 0; i < nstates; i++)
set_conflicts (states[i]);
void
-free_conflicts (void)
+conflicts_free (void)
{
XFREE (conflicts);
bitset_free (shiftset);
bitset_free (lookaheadset);
+ obstack_free (&solved_conflicts_obstack, NULL);
}
/* Find and resolve or report look-ahead conflicts for bison,
- Copyright 2000, 2001 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
# define CONFLICTS_H_
# include "state.h"
-void solve_conflicts PARAMS ((void));
+void conflicts_solve PARAMS ((void));
void conflicts_print PARAMS ((void));
void conflicts_output PARAMS ((FILE *out));
-void free_conflicts PARAMS ((void));
+void conflicts_free PARAMS ((void));
/* Were there conflicts? */
extern int expected_conflicts;
"state", "states",
"itemset", "itemsets",
"lookahead", "lookaheads",
+ "solved",
"all",
0
};
report_states, report_states,
report_states | report_itemsets, report_states | report_itemsets,
report_states | report_lookaheads, report_states | report_lookaheads,
+ report_states | report_solved_conflicts,
report_all
};
`state' describe the states\n\
`itemset' complete the core item sets with their closure\n\
`lookahead' explicitly associate lookaheads to items\n\
+ `solved' describe shift/reduce conflicts solving\n\
`all' include all the above information\n\
`none' disable the report\n\
"), stream);
report_states = 1 << 0,
report_itemsets = 1 << 1,
report_lookaheads = 1 << 2,
+ report_solved_conflicts = 1 << 3,
report_all = ~0
};
lookahead is not enough to disambiguate the parsing. In file
conflicts. Also resolve s/r conflicts based on precedence
declarations. */
- solve_conflicts ();
+ conflicts_solve ();
conflicts_print ();
/* Output file names. */
output ();
reduce_free ();
- free_conflicts ();
+ conflicts_free ();
free_nullable ();
free_derives ();
grammar_free ();
fputs ("\n\n", out);
print_core (out, state);
print_actions (out, state);
+ if ((report_flag & report_solved_conflicts)
+ && state->solved_conflicts)
+ fputs (state->solved_conflicts, out);
fputs ("\n\n", out);
}
\f
short lookaheadsp;
int nlookaheads;
- /* Its items. */
+ /* If some conflicts were solved thanks to precedence/associativity,
+ a human readable description of the resolution. */
+ const char *solved_conflicts;
+
+ /* Its items. Must be last, since ITEMS can be arbitrarily large.
+ */
unsigned short nitems;
item_number_t items[1];
} state_t;
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison input.y -o input.c -v], 0, [],
+AT_CHECK([bison input.y -o input.c --report=all], 0, [],
[input.y contains 1 shift/reduce conflict.
])
state 0
$axiom -> . exp $ (rule 0)
+ exp -> . exp OP exp (rule 1)
+ exp -> . NUM (rule 2)
NUM shift, and go to state 1
state 4
+ exp -> . exp OP exp (rule 1)
exp -> exp OP . exp (rule 1)
+ exp -> . NUM (rule 2)
NUM shift, and go to state 1
state 5
- exp -> exp . OP exp (rule 1)
- exp -> exp OP exp . (rule 1)
+ exp -> exp . OP exp [$, OP] (rule 1)
+ exp -> exp OP exp . [$, OP] (rule 1)
OP shift, and go to state 4
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison input.y -o input.c -v], 0, [], [])
+AT_CHECK([bison input.y -o input.c --report=all], 0, [], [])
# Check the contents of the report.
AT_CHECK([cat input.output], [],
-[[Conflict in state 5 between rule 2 and token OP resolved as shift.
-
-
-Grammar
+[[Grammar
Number, Line, Rule
0 4 $axiom -> exp $
state 0
$axiom -> . exp $ (rule 0)
+ exp -> . exp OP exp (rule 1)
+ exp -> . NUM (rule 2)
NUM shift, and go to state 1
state 4
+ exp -> . exp OP exp (rule 1)
exp -> exp OP . exp (rule 1)
+ exp -> . NUM (rule 2)
NUM shift, and go to state 1
state 5
- exp -> exp . OP exp (rule 1)
- exp -> exp OP exp . (rule 1)
+ exp -> exp . OP exp [$] (rule 1)
+ exp -> exp OP exp . [$] (rule 1)
OP shift, and go to state 4
$default reduce using rule 1 (exp)
+ Conflict between rule 2 and token OP resolved as reduce (%right OP).
]])
projects / bison.git / commitdiff
