Suggesting -Wcounterexamples when there are conflicts is probably not
what the user wants. If she knows her conflicts and has set
%expect/%expect-rr appropriately, we shouldn't warn.
The commit also swaps the counterexamples and the report of conflicts,
into, IMHO, a more natural order: from
Shift/reduce conflict on token B:
1: 3 a: A .
1: 8 y: A . B
Example A • B C
First derivation s ::=[ a ::=[ A • ] x ::=[ B C ] ]
Example A • B C
Second derivation s ::=[ y ::=[ A • B ] c ::=[ C ] ]
input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
to
input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token B:
1: 3 a: A .
1: 8 y: A . B
Example A • B C
First derivation s ::=[ a ::=[ A • ] x ::=[ B C ] ]
Example A • B C
Second derivation s ::=[ y ::=[ A • B ] c ::=[ C ] ]
input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
* src/conflicts.c (rule_conflicts_print): Rename as...
(report_rule_expectation_mismatches): this.
Move the handling of report_counterexamples to...
(conflicts_print): Here.
Display this warning when applicable.
Plural vs. singular is always a problem...
But we already have conflicts-sr and conflicts-rr, so counterexamples
makes more sense than counterexample. Besides, -Wcounterexample will
still be accepted as an unambiguous prefix of -Wcounterexamples.
Add -Wcex as a convenient alias.
While at it, use only "counterexample", never "counter example".
* src/complain.h, src/complain.c
(Wcounterexample, warning_counterexample): Rename as...
(Wcounterexamples, warning_counterexamples): these.
(argmatch_warning_docs): Rename -Wcounterexample as -Wcounterexamples.
(argmatch_warning_args): Likewise.
Add support for -Wcex.
Adjust dependencies.
Use colors to show the counterexamples and the derivations in color,
to highlight their structure. Align the outputs, and add i18n
support. Reduce width by using a one-space separator instead of
two-space.
From
Example A • B C
First derivation s ::=[ a ::=[ A • ] x ::=[ B C ] ]
Second derivation s ::=[ y ::=[ A • B ] c ::=[ C ] ]
to
Example A • B C
First derivation s ::=[ a ::=[ A • ] x ::=[ B C ] ]
Example A • B C
Second derivation s ::=[ y ::=[ A • B ] c ::=[ C ] ]
with colors.
* data/bison-default.css (cex-dot, cex-0, cex-1, cex-2, cex-3, cex-4)
(cex-5, cex-6, cex-7, cex-step, cex-leaf): New.
* src/derivation.c (derivation_print_styled_impl): New.
(derivation_print, derivation_print_leaves): Use it.
* src/counterexample.c: Reformat the output.
* tests/counterexample.at: Adjust.
It's unfortunate that the traditions between formal language theory
and Yacc differs, but here, tokens should be upper case, and
nonterminals should be lower case.
* tests/counterexample.at: Comply with this.
In Bison we refer to "shift/reduce" conflicts, not "shift-reduce" (in
Bison 3.6.3 186 occurrences vs 15). Enforce consistency on this.
Instead of "spending" a second line for each conflict to report the
lookaheads, put that on the same line as the type of conflict. Also,
prefer "token" to "symbol". Maybe we should even prefer "lookahead".
While at it, enable internationalization, with plurals where
appropriate.
As a consequence, instead of
Shift-Reduce Conflict:
6: 3 b: . %empty
6: 6 d: c . A
On Symbol: A
display
Shift/reduce conflict on token A:
6: 3 b: . %empty
6: 6 d: c . A
* NEWS, doc/bison.texi, src/conflicts.c: Spell it "shift/reduce", not
"shift-reduce".
* src/counterexample.c (counterexample_report_shift_reduce)
(counterexample_report_reduce_reduce): Reformat and internationalize
output.
* tests/counterexample.at: Adjust expectations.
Instead of `On Symbols: {b,c,}`, display `On Symbols: b, c`.
* src/counterexample.c (counterexample_report_reduce_reduce): We don't
need braces.
Use commas as a separator, not a terminator.
* tests/counterexample.at: Adjust.
The CI has "failures" such as (253, "Null nonterminals"):
@@ -21,7 +21,7 @@
3: 3 b: . %empty
3: 4 c: . %empty
On Symbols: {A,}
-time limit exceeded: 6.000000
+time limit exceeded: 11.000000
First Example c • c A A $end
First derivation $accept ::=[ a ::=[ c d ::=[ a ::=[ b ::=[ • ] d ::=[ c A A ] ] ] ] $end ]
Second Example c • A $end
* tests/counterexample.at (AT_BISON_CHECK_CEX): New.
Use it to neutralize differences in timeout values.
* src/parse-simulation.c: Replace reference counting with
parse_state_retain everywhere.
(free_parse_state): Make this function iterative instead of
recursive. Long parse_state chains were causing stack exhaustion.
* tests/counterexample.at: Fix expectations.
Fixes the SEGV in test 247 (counterexample.at:195): "S/R after first
token".
* src/counterexample.c: here.
* tests/counterexample.at: Fix expectations.
* src/counterexample.c, src/derivation.c:
Do not output diagnostics on stdout, that's the job of stderr, and the
testsuite heavily depend on this.
Do not leave trailing spaces in the output.
* tests/counterexample.at: Use AT_KEYWORDS.
Specify the expected outputs.
* tests/local.mk: Add counterexample.at.
