This follows from a discussion with Ernesto Posse.
The semantics for the {...} operator we use in Spot comes from the
cl(...) operator defined by Dax et al. (ATVA'09). This is slightly
different from the the way the PSL spec interprets a SERE used in the
context of a temporal formula (appendix B.3.1.1.2, item 7).
cl({a;b}[*]) would match any infinite word that starts with a;b, while
in PSL {a;b}[*] would match any infinite word that alternates a and b.
Spot documents that {SERE} in a temporal formula is interpreted like
cl(SERE) however it failed to ignore the empty prefix of SERE. So
{{a;b}[*]} would match anything, because the empty word is a prefix of
any word, and is also accepted by {a;b}[*]. Some trivial identities
and basic rewritings were also wrongly considering these empty
prefixes as well.
This patch therefore fixes the translation and syntactic
simplification rules, to really ignore these empty prefixes.
In some future version it should probably be wise to rename this {...}
operator as cl(...), and use {...} for the semantics given in appendix
B.3.1.1.2 (item 7) of the PSL specs.
* src/ltlast/unop.cc: Fix trivial identities. We have
{[*0]} = 0 and !{[*0]} = 1.
* src/ltlvisit/simplify.cc: Fix basic rewriting rules.
{e[*]} = {e} and !{e[*]} = !{e}.
* doc/tl/tl.tex: Adjust documentation.
* doc/tl/tl.bib (dax.09.atva): New entry.
* src/tgbaalgos/ltl2tgba_fm.cc: Do not accept any
infinite word for {e[*]} just because the empty
prefix is matched by e[*].
* src/tgbatest/ltl2tgba.test: Add a test case.
* NEWS: Mention it.
* THANKS: Add Ernesto.
Also accept guards of the form (a) || !(b) or (a) && !(b).
* src/neverparse/neverclaimscan.ll: Adjust.
* src/tgbatest/neverclaimread.test: Add a test case.
These translator may output guards such as (a) || (b), but with the
changes in Spot 1.1.3 it would only work with ((a) || (b)).
Furthermore when ltlcross would fail to parse a neverclaim containing
such a guard, it would fail to parse all later neverclaims, because
the lexer was not properly reset.
* src/neverparse/neverclaimscan.ll: Scan (a) || (b) as a single
token.
(neverclaimyyopen): Reset the lexer.
* src/tgbatest/neverclaimread.test: Add a test for (a) || (b).
* NEWS: Update.
* src/neverparse/neverclaimparse.yy, src/neverparse/neverclaimscan.ll:
Allow transitions between do..od, recognize atomic and assert.
* src/neverparse/parsedecl.hh: Pass the error_list to the lexer.
* src/tgbatest/neverclaimread.test: Add a test case.
If all the acceptance set of an SCC but the first one were useless, the
scc_filter() algorithm could abort with a BDD error because of a bug in
the logic.
* src/tgbaalgos/sccfilter.cc (scc_filter): Fix.
* src/tgbatest/sccsimpl.test: Add a test case supplied by Étienne
Renault.
* doc/Doxyfile.in: Update to Doxygen 1.8.4
* doc/footer.html: Point to the mailing list.
* doc/mainpage.dox: Point to spot::translator,
and spot::kripke.
* src/ta/tgta.hh: Do not use \emph.
* src/tgba/succiter.hh: Fix rendering of example.
* src/tgba/tgba.hh: Correct documentation.
* src/tgbaalgos/cycles.hh: Improve rendering of
documentation.
* src/tgbaalgos/lbtt.hh, src/tgbaalgos/minimize.hh:
Document missing arguments.
* src/bin/ltlcross.cc: Implement the new option. Average the product
statistics on all products.
* src/tgbatest/basimul.test, src/tgbatest/ltlcross.test,
src/tgbatest/ltlcross2.test, bench/ltl2tgba/tools: Use the new option.
* NEWS: Mention it.
* src/tgba/bdddict.cc, src/tgba/bdddict.hh
(unregister_all_typed_variables): New method.
* src/tgbaalgos/degen.cc (degeneralize): Use it.
* NEWS: Mention it.
* src/tgbaalgos/simulation.hh, src/tgbaalgos/simulation.cc
(simulation_sba, cosimulation_sba, iterated_simulations_sba): New
function. Also speedup the existing functions by avoiding
add_acceptince_conditions() and add_conditions(). Finally, use
scc_filter_states() when dealing with degeneralized automata.
* src/tgbaalgos/postproc.cc, src/tgbaalgos/postproc.hh (do_ba_simul):
New method. Use it after degeneralization.
* src/tgba/tgbaexplicit.hh (get_transition, get_state): New methods.
* src/tgbatest/basimul.test: New file.
* src/tgbatest/Makefile.am (TESTS): Add it.
* NEWS: Introduce the new function and summarize the bug.
The main motivation is the upcoming patch that introduces
simulation_sba() and requires this function.
* src/tgbaalgos/sccfilter.hh, src/tgbaalgos/sccfilter.cc: Implement it.
* src/tgbaalgos/postproc.cc: Use it for monitors, because we do not
care about acceptance conditions.
* NEWS: Mention it.
* src/bin/ltlfilt.cc: Handle --universal and --eventual. Match
only LTL formulas with --stutter-invariant.
* src/ltltest/ltlfilt.test: New file.
* src/ltltest/Makefile.am (TESTS): Add it.
* NEWS: Mention these bug fixes.
Provide a way to output automata with state-based acceptance. Also
print the guards using to_lbt_string() for consistency: as a
consequence, atomic proposition that do not match p[0-9]+ are now
double-quoted.
* src/tgbaalgos/lbtt.hh (lbtt_reachable): Add a sba option.
* src/tgbaalgos/lbtt.cc: Implement it, and use to_lbt_string().
* src/ltlvisit/lbt.cc (is_pnum): Reject 'p' without number.
* src/bin/ltl2tgba.cc: Activate the sba option of --ba was given.
Add an option --lbtt=t to get the old behavior.
* src/bin/man/ltl2tgba.x: Document the LBTT format we use with
some links and examples.
* src/tgbatest/lbttparse.test: More tests.
* src/tgbatest/ltlcross2.test: Add a check with --lbtt --ba.
* NEWS: Update.
* wrap/python/ajax/ltl2tgba.html: Augment and update tooltips to match
vocabulary in the Spin'13 paper. Hide the compose obligation option
since it's a work in progress.
