It does not make a lot of sense to use ::= in our counterexamples,
that's not something that belongs to the Bison "vocabulary". Using
the colon makes sense, but it's too discreet. Let's use the arrow,
which we already use in some reports (HTML and Dot).
* src/gram.h (print_dot_fallback): Generalize into...
(print_fallback): this.
(print_arrow): New.
* src/derivation.c: Use it.
* NEWS, tests/conflicts.at, tests/counterexample.at,
* tests/diagnostics.at, tests/report.at: Adjust.
* doc/bison.texi: Ditto.
Unfortunately the literal `→` is output as `↦`. So we need to use
@arrow.
I implemented this to print A ::= [ ], but A ::= [ %empty ] might be
clearer.
* src/parse-simulation.c (nullable_closure): Don't generate null
nonterminal derivations as leaves.
* src/derivation.c (derivation_print_impl): Don't print seperator
spaces for null nonterminal.
* tests/counterexample.at: Update test results.
Use of print_unicode_char suggested by Bruno Haible.
https://lists.gnu.org/r/bug-gettext/2020-06/msg00012.html
* src/gram.h (print_dot_fallback, print_dot): New.
* src/gram.c, src/derivation.c: Use it.
* tests/counterexample.at, tests/report.at: Adjust the test suite.
* .travis.yml, README-hacking.md: Adjust.
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.
First, we should avoid code such as
gl_list_iterator_t it = gl_list_iterator (deriv->children);
derivation *child = NULL;
while (gl_list_iterator_next (&it, (const void **) &child, NULL))
{
derivation_print (child, f);
because of -Wstrict-aliasing (whose job is to catch type-punning
issues). See https://lists.gnu.org/r/bug-bison/2020-05/msg00039.html.
Rather we need
gl_list_iterator_t it = gl_list_iterator (deriv->children);
const void **p = NULL;
while (gl_list_iterator_next (&it, &p, NULL))
{
derivation *child = (derivation *) p;
derivation_print (child, f);
Second, list iterators actually have destructors. Even though they
are noop in the case of linked-lists, we should use them.
Let's address both issues with typed wrappers (such as
derivation_list_next) that take care of both issues, and besides allow
to scope the iterators within the loop:
derivation *child;
for (gl_list_iterator_t it = gl_list_iterator (deriv->children);
derivation_list_next (&it, &child);
)
{
derivation_print (child, f);
* src/derivation.h, src/derivation.c (derivation_list_next): New.
Use it where appropriate.
* src/counterexample.c (search_state_list_next): New.
Use it where appropriate.
* src/parse-simulation.h, src/parse-simulation.c
* src/state-item.h (state_item_list_next): New.
Use it where appropriate.
* src/derivation.h, src/derivation.c: Make derivation struct opaque.
Add derivation_list type for clarity.
(derivation_list_new): New.
(derivation_list_append): New.
(derivation_list_prepend): New.
(derivation_new_leaf): New constructor for derivations with no
children.
* src/counterexample.c, src/parse-simulation.c,
* src/parse-simulation.h: Replace uses of gl_list_t containing
derivations with derivation_list and its API.
Replace calls of dervation_new using null children with
derivation_new_leaf.
* src/parse-simulation.c: replace ps_chunk and its API with typed
versions si_chunk and deriv_chunk.
* src/parse-simlation.h, src/parse-simulation.c: Remove
parse_state_retain_deriv in favor of derivation reference counting.
* src/counterexample.c: Remove search_state_retain_deriv.
* 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.
