The set of rules enabled by favor_even_univ try to "lift" the
subformulae that are both eventual and universal, so they appear
higher in the AST. This is contrary to what we used to do (and still
do when the option is unset), were we try to postpone such subformulae
(by moving them down the AST). It is still a bit experimental.
* src/ltlvisit/simplify.hh: Add option favor_event_univ.
* src/ltlvisit/simplify.cc: Implement new rewriting rules.
* doc/tl/tl.tex: Document them.
* src/tgbatest/ltl2tgba.cc: Add option -ra to enable them.
* src/tgbatest/spotlbtt.test: Test the translation with this option.
* src/ltltest/reduc.cc, src/ltltest/equals.cc: Add option
to enable the new rules.
* src/ltltest/eventuniv.test: New file to test them.
* src/ltltest/Makefile.am: Add it.
* src/bin/ltlfilt.cc: Add options --remove-x and --stutter-invariant.
* src/ltlvisit/remove_x.cc, src/ltlvisit/remove_x.hh: New files.
* src/ltlvisit/Makefile.am: Add them.
* src/ltltest/remove_x.test: New file.
* src/ltltest/Makefile.am: Add it.
* NEWS: Mention the new algorithms.
When something like XFa & FXa is reduced, the subformulae XFa and FXa
are both rewritten separately to XFa, and then the vector of arguments
of the And operators, [XFa,XFa], is passed through a specialized loop
that searches of the form X(...) that can potentially be simplified with
some other terms. This loop converts the vector [XFa,XFa] into the set
{XFa,XFa}={XFa} and forgot to deal with the case where the insertion
would actually not add an existing subformula.
* src/ltlvisit/simplify.cc: Fix the code for Or, and And.
* src/ltltest/reduc0.test: New file, to test it.
* src/ltltest/Makefile.am (TESTS): Add it.
* src/ltltest/reduccmp.test: Add an extra test that does not
trigger the bug (because reduccmp.test uses more than basic
optimizations, and the implication-based simplifications are
already able to detect that XFa and FXa are equivalent).
* src/ltlvisit/tostring.cc: Allow '.' in bare words while
printing atomic propositions.
* src/ltltest/bare.test: New file.
* src/ltltest/Makefile.am: Add it.
* src/ltlvisit/wmunabbrev.cc: Fix clone() order.
* src/ltltest/equals.cc: Add a mode for unabbreviate_wm().
* src/ltltest/unabbrevwm.test: New file.
* src/ltltest/Makefile.am: Add it.
* src/ltlvisit/tostring.hh, src/ltlvisit/tostring.cc
(to_wring_string): New option.
* src/bin/common_output.hh, src/bin/common_output.cc:
Add support for a --wring option.
* src/bin/ltlcheck.cc: Add %w and %W format specifiers.
Spin 6 supports formulas such as []<>(a < b) so that atomic properties
need not be specified using #define. Of course we don't want to
implement all the syntax of Spin in our LTL parser because other tools
may have different syntaxes for their atomic propositions. The
lenient mode tells the scanner to return any (...), {...}, or {...}!
block as a single token. The parser will try to recursively parse
this block as a LTL/SERE formula, and if this fails, it will consider
the block to be an atomic proposition. The drawback is that most
syntax errors will no be considered to be atomic propositions. For
instance (a U b U) is a single atomic proposition in lenient mode, and
a syntax error in default mode.
* src/ltlparse/ltlparse.yy, src/ltlparse/ltlscan.ll,
src/ltlparse/parsedecl.hh, src/ltlparse/public.hh: Add a
lenient parsing mode. Simplify the lexer using yy_scan_string.
* src/bin/common_finput.cc: Add a --lenient option.
* src/ltltest/lenient.test: New file.
* src/ltltest/Makefile.am: Add it.
* src/neverparse/neverclaimparse.yy: Parse the guards in lenient mode.
* src/tgbatest/neverclaimread.test: Adjust.
* src/ltlvisit/tostring.cc: When outputing a formula in Spin's syntax,
output (a < b) instead of "a < b".
* src/misc/escape.cc, src/misc/escape.hh (trim): New helper function.
We used to output 0 and 1, but "spin -f" does not under understand
that.
* src/ltlvisit/tostring.cc (kw_spin): Output true and false instead of
0 and 1.
* src/ltlvisit/lbt.cc, src/ltlvisit/lbt.hh: New files.
* src/ltlvisit/Makefile.am: Add them.
* src/bin/common_output.cc, src/bin/common_output.hh: Add
support for LBT output, and reporting formulae that cannot
be output in this syntax.
* src/bin/ltlfilt.cc: Pass filename and linenum to
output_formula() for better error reporting.
* src/eltlparse/Makefile.am, src/ltlvisit/randomltl.cc,
src/ltlvisit/simplify.cc, src/ltlvisit/snf.cc, src/ltlvisit/snf.hh:
Fix GPL to version 2 or later.
Doing so will release all BDD variables used by automata created for
syntactic implication. This way the main translation will create
acceptance variables again in a more natural order, which will help
the degeneralization (until we get a better degeneralization).
* src/ltlvisit/contain.cc, src/ltlvisit/contain.hh
(language_containment_checker::clear): New method to clear the
containment cache.
* src/ltlvisit/simplify.cc, src/ltlvisit/simplify.hh
(clear_as_bdd_cache): Also call language_containment_checker::clear.
Syntactic implication checks may use as_bdd() to compare Boolean
formulae. By doing so, they register Boolean variables in an order
that is usially detrimental to the LTL translator. The new,
clear_as_bdd_cache() function offers a mean to unregister these
variables, so that the LTL translator will register them again in the
a more natural way.
* src/ltlvisit/simplify.hh, src/ltlvisit/simplify.cc
(clear_as_bdd_cache): New function.
* src/tgbatest/ltl2tgba.cc, wrap/python/ajax/spot.in: Call it.
* src/ltlvisit/simplify.cc
(ltl_simplifier_cache::syntactic_implication): If the lhs and rhs are
literals that are not equal, return false immediately.
We need a marked version of !{r} to perform breakpoint unroling.
* src/ltlast/unop.cc, src/ltlast/unop.hh: Declare a NegClosureMarked
operator.
* src/ltlvisit/mark.hh, src/ltlvisit/mark.cc,
src/tgbaalgos/ltl2tgba_fm.cc: Adjust to deal with NegClosureMarked
and NegClosure as apropriate.
* src/ltlvisit/simplify.cc, src/ltlvisit/tostring.cc,
src/ltlvisit/tunabbrev.cc, src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/ltl2tgba_lacim.cc,
src/tgba/formula2bdd.cc: Deal with NegClosureMarked in the same way as
we deal with NegClosure.
* src/tgbatest/ltl2tgba.test: More tests.
* src/ltltest/kind.test: Adjust.
* doc/tl/tl.tex: Mention the marked negated closure.
* src/ltlvisit/wmunabbrev.hh, src/ltlvisit/wmunabbrev.cc: New files.
* src/ltlvisit/Makefile.am: Add them.
* src/ltlvisit/tostring.cc (to_spin_string): Use the new rewriting.
* wrap/python/ajax/spot.in: Warn when a "Spin" still contain PSL
operators.
* wrap/python/ajax/ltl2tgba.html: Adjust help text.
* doc/tl/tl.tex, NEWS: Document the new rewriting.
* src/ltlparse/ltlscan.ll: Understand the combining overline, and
combining overbar as synonym for =0.
* src/ltlvisit/tostring.cc: Emit a combining overline for
single-letter atomic propositions.
* src/ltlast/atomic_prop.hh (is_atomic_prop): New function.
* doc/tl/tl.tex: Document these two characters.
* src/ltlvisit/simplify.cc (reduce_sere_ltl): New function,
to factor the code of the []-> and <>-> rewrittings.
* src/ltltest/reduccmp.test: Add more tests.
* doc/tl/tl.tex: Document these rewritings.
* src/ltlvisit/simplify.cc: Here.
* doc/tl/tl.tex: Document then.
* src/ltlast/bunop.hh (as_KleenStar): New helper function.
* src/ltltest/reduccmp.test: Add more tests.
* src/ltltest/reduc.cc: Also display the resulting formula
without reduce_size_stricly.
