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cex: also include the counterexamples in the report

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The report is the best place to show the details about
counterexamples, since we have the state right under the nose.

For instance:

State 7

    1 exp: exp . "⊕" exp
    2    | exp . "+" exp
    2    | exp "+" exp .  [$end, "+", "⊕"]
    3    | exp . "+" exp
    3    | exp "+" exp .  [$end, "+", "⊕"]

    "⊕"  shift, and go to state 6

    $end      reduce using rule 2 (exp)
    $end      [reduce using rule 3 (exp)]
    "+"       reduce using rule 2 (exp)
    "+"       [reduce using rule 3 (exp)]
    "⊕"       [reduce using rule 2 (exp)]
    "⊕"       [reduce using rule 3 (exp)]
    $default  reduce using rule 2 (exp)

    Conflict between rule 2 and token "+" resolved as reduce (%left "+").

    Shift/reduce conflict on token "⊕":
        2 exp: exp "+" exp .
        1 exp: exp . "⊕" exp
      Example                  exp "+" exp • "⊕" exp
      First derivation         exp ::=[ exp ::=[ exp "+" exp • ] "⊕" exp ]
      Example                  exp "+" exp • "⊕" exp
      Second derivation        exp ::=[ exp "+" exp ::=[ exp • "⊕" exp ] ]

    Reduce/reduce conflict on tokens $end, "+", "⊕":
        2 exp: exp "+" exp .
        3 exp: exp "+" exp .
      Example                  exp "+" exp •
      First derivation         exp ::=[ exp "+" exp • ]
      Example                  exp "+" exp •
      Second derivation        exp ::=[ exp "+" exp • ]

    Shift/reduce conflict on token "⊕":
        3 exp: exp "+" exp .
        1 exp: exp . "⊕" exp
      Example                  exp "+" exp • "⊕" exp
      First derivation         exp ::=[ exp ::=[ exp "+" exp • ] "⊕" exp ]
      Example                  exp "+" exp • "⊕" exp
      Second derivation        exp ::=[ exp "+" exp ::=[ exp • "⊕" exp ] ]

* src/conflicts.h, src/conflicts.c (has_conflicts): New.
* src/counterexample.h, src/counterexample.c (print_counterexample):
Add a `prefix` argument.
(counterexample_report_shift_reduce)
(counterexample_report_reduce_reduce): Show the items when there's a
prefix.
* src/state-item.h, src/state-item.c (print_state_item):
Add a `prefix` argument.
* src/derivation.h, src/derivation.c (derivation_print)
(derivation_print_leaves): Add a prefix argument.
* src/print.c (print_state): When -Wcex is enabled, show the
conflicts.
* tests/report.at: Adjust.
This commit is contained in:
Akim Demaille
2020-06-11 08:24:30 +02:00
parent 35c0fe6789
commit d4f854e5b2
13 changed files with 158 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
src/counterexample.c
View File

@@ -100,17 +100,21 @@ free_counterexample (counterexample *cex)
}
static void
print_counterexample (counterexample *cex, FILE *out)
print_counterexample (counterexample *cex, FILE *out, const char *prefix)
{
fprintf (out, " %-20s ", cex->unifying ? _("Example") : _("First example"));
derivation_print_leaves (cex->d1, out);
fprintf (out, " %-20s ", _("First derivation"));
derivation_print (cex->d1, out);
fprintf (out, " %s%-20s ",
prefix, cex->unifying ? _("Example") : _("First example"));
derivation_print_leaves (cex->d1, out, prefix);
fprintf (out, " %s%-20s ",
prefix, _("First derivation"));
derivation_print (cex->d1, out, prefix);
fprintf (out, " %-20s ", cex->unifying ? _("Example") : _("Second example"));
derivation_print_leaves (cex->d2, out);
fprintf (out, " %-20s ", _("Second derivation"));
derivation_print (cex->d2, out);
fprintf (out, " %s%-20s ",
prefix, cex->unifying ? _("Example") : _("Second example"));
derivation_print_leaves (cex->d2, out, prefix);
fprintf (out, " %s%-20s ",
prefix, _("Second derivation"));
derivation_print (cex->d2, out, prefix);
fputc ('\n', out);
}
@@ -469,7 +473,7 @@ nonunifying_shift_path (gl_list_t reduce_path, state_item *shift_conflict)
for (gl_list_iterator_t it = gl_list_iterator (result);
state_item_list_next (&it, &sip);
)
print_state_item (sip, stderr);
print_state_item (sip, stderr, "");
}
return result;
}
@@ -1175,7 +1179,7 @@ counterexample_free (void)
static void
counterexample_report (state_item_number itm1, state_item_number itm2,
symbol_number next_sym, bool shift_reduce,
FILE *out)
FILE *out, const char *prefix)
{
// Compute the shortest lookahead-sensitive path and associated sets of
// parser states.
@@ -1204,23 +1208,32 @@ counterexample_report (state_item_number itm1, state_item_number itm2,
: example_from_path (shift_reduce, itm2, shortest_path, next_sym);
gl_list_free (shortest_path);
print_counterexample (cex, out);
print_counterexample (cex, out, prefix);
free_counterexample (cex);
}
static void
counterexample_report_shift_reduce (state_item_number itm1, state_item_number itm2,
symbol_number next_sym, FILE *out)
symbol_number next_sym,
FILE *out, const char *prefix)
{
fputs (prefix, out);
fprintf (out, _("Shift/reduce conflict on token %s:\n"), symbols[next_sym]->tag);
counterexample_report (itm1, itm2, next_sym, true, out);
if (*prefix)
{
print_state_item (&state_items[itm1], out, prefix);
print_state_item (&state_items[itm2], out, prefix);
}
counterexample_report (itm1, itm2, next_sym, true, out, prefix);
}
static void
counterexample_report_reduce_reduce (state_item_number itm1, state_item_number itm2,
bitset conflict_syms, FILE *out)
bitset conflict_syms,
FILE *out, const char *prefix)
{
{
fputs (prefix, out);
fputs (ngettext ("Reduce/reduce conflict on token",
"Reduce/reduce conflict on tokens",
bitset_count (conflict_syms)), out);
@@ -1234,7 +1247,12 @@ counterexample_report_reduce_reduce (state_item_number itm1, state_item_number i
}
fputs (_(":\n"), out);
}
counterexample_report (itm1, itm2, bitset_first (conflict_syms), false, out);
if (*prefix)
{
print_state_item (&state_items[itm1], out, prefix);
print_state_item (&state_items[itm2], out, prefix);
}
counterexample_report (itm1, itm2, bitset_first (conflict_syms), false, out, prefix);
}
static state_item_number
@@ -1248,7 +1266,7 @@ find_state_item_number (const rule *r, state_number sn)
}
void
counterexample_report_state (const state *s, FILE *out)
counterexample_report_state (const state *s, FILE *out, const char *prefix)
{
const state_number sn = s->number;
const reductions *reds = s->reductions;
@@ -1265,7 +1283,7 @@ counterexample_report_state (const state *s, FILE *out)
if (item_number_is_symbol_number (conf)
&& bitset_test (reds->lookahead_tokens[i], conf))
{
counterexample_report_shift_reduce (c1, j, conf, out);
counterexample_report_shift_reduce (c1, j, conf, out, prefix);
break;
}
}
@@ -1287,7 +1305,7 @@ counterexample_report_state (const state *s, FILE *out)
const rule *r = item_rule (si->item);
if (r == r2)
{
counterexample_report_reduce_reduce (c1, k, conf, out);
counterexample_report_reduce_reduce (c1, k, conf, out, prefix);
break;
}
}