Spot 1.2.4 has been released.
This maintenance release fixes a crashing scenario in the translation
of testing automata, a couple of incorrect PSL simplifications, and a
bug in the translation of the fusion operator.
You can download the new release here:
http://spot.lip6.fr/dl/spot-1.2.4.tar.gz
New in spot 1.2.4 (2014-05-15)
* New features:
- "-B -x degen-lskip" can be used to disable level-skipping in the
degeralization procedure called by ltl2tgba and dstar2tgba.
This is mostly meant for running experiments.
- "-B -x degen-lcache=N" can be used to experiment with different
type of level caching during degeneralization.
* Bug fixes:
- Change the Python bindings to make them compatible with Swig 3.0.
- "ltl2tgta --ta" could crash in certain conditions due to the
introduction of a simulation-based reduction after
degeneralization.
- Fix four incorrect formula-simplification rules, three were
related to the factorization of Boolean subformulas in
operands of the non-length-matching "&" SERE operator, and
a fourth one could only be enabled by explicitely passing the
favor_event_univ option to the simplifier (not the default).
- Fix incorrect translation of the fusion operator (":") in SERE
such as {xx;1}:yy[*] where the left operand has 1 as tail.
--
Alexandre Duret-Lutz
We are happy to announce that Spot 1.2.3 has been released.
This maintenance release addresses more portability issues and other
minor bugs listed below. It also supports a new SPOT_SATLOG
environment variable to extra more statistics from our SAT-based
minimization procedures.
It contains contributions from Alexandre Lewkowicz and Étienne
Renault.
You can download the new release here:
http://spot.lip6.fr/dl/spot-1.2.3.tar.gz
New in spot 1.2.3 (2014-02-11)
* New features:
- The SPOT_SATLOG environment variable can be set to a filename to
obtain statistics about the different iterations of the
SAT-based minimization. For an example, see
http://spot.lip6.fr/userdoc/satmin.html
- The bench/dtgbasat/ benchmark has been updated to use SPOT_SATLOG
and record more statistics.
- The default value for the SPOT_SATSOLVER environment
variable has been changed to "glucose -verb=0 -model %I >%O".
This assumes that glucose 3.0 is installed. For older
versions of glucose, remove the "-model" option.
* Bug fixes:
- More fixes for Python 3 compatibility.
- Fix calculation of length_boolone(), were 'Xa|b|c' was
considered as length 6 instead of 4 (because it is 'Xa|(b|a)'
were (b|a) is Boolean).
- Fix Clang-3.5 warnings.
- randltl -S did not honor --boolean-priorities.
- randltl had trouble generating formulas when all unary, or
all binary/n-ary operators were disabled.
- Fix spurious testsuite failure when using Pandas 0.13.
- Add the time spent in child processes when measuring time
with the timer class.
- Fix determinism of the SAT-based minimization encoding.
(It would sometimes produce different equivalent automata,
because of a different encoding order.)
- A the SAT-based minimization is asked for a 10-state automaton
and return a 6-state automaton, do not ask for a 9-state
automaton in the next iteration...
- Fix some compilation issue with the version of Apple's Clang
that is installed with MacOS X 10.9.
- Fix VPATH builds when building from the git repository.
- Fix UP links in the html documentation for command-line tools.
--
Alexandre Duret-Lutz
I'm happy to announce that Spot 1.2.2 has been released.
This maintenance release addresses a couple of portability issues and
other minor bugs discovered over the last month.
You can download the new release here:
http://spot.lip6.fr/dl/spot-1.2.2.tar.gz
New in spot 1.2.2 (2014-01-24)
* Bug fixes:
- Fix compilation *and* behavior of bitvectors on 32-bit
architectures.
- Fix some compilation errors observed using the antique G++ 4.0.1.
- Fix compatibility with Python 3 in the test suite.
- Fix a couple of new clang warnings (like "unused private member").
- Add some missing #includes that are not included indirectly
when the C++ compiler is in C++11 mode.
- Fix detection of numbers that are too large in the ELTL parser.
- Fix a memory leak in the ELTL parser, and avoid some unnecessary
calls to strlen() at the same time.
--
Alexandre Duret-Lutz
I'm happy to announce that Spot 1.2.1 has been released.
These release improves the CSV reporting of ltlcross (including size
for Rabin or Streett automata, separate measurements in case multiple
products are used, and information about the exit status of the
translators). As a consequence the order of columns has changed
slightly, and it will break scripts that use hardcoded column
positions. If you want to get a CSV output that is closest to what
ltlcross used to output before, use the --omit-missing option (but
even with that the "time" column has been shifted left). Other tools
have also learned how to read CSV files, and have some options to help
creating CSV files.
You can download the new release here:
http://spot.lip6.fr/dl/spot-1.2.1.tar.gz
New in spot 1.2.1 (2013-12-11)
* New features:
- commands for translators specified to ltlcross can now
be given "short names" to be used in the CSV or JSON output.
For instance
ltlcross '{small} ltl2tgba -s --small %f >%N' ...
will run the command "ltl2tgba -s --small %f >%N", but only
print "small" in output files.
- ltlcross' CSV and JSON output now contains two additional
columns: exit_status and exit_code, used to report failures of
the translator. If the translation failed, only the time is
reported, and the rest of the statistics, which are missing,
area left empty (in CVS) or null (in JSON). A new option,
--omit-missing can be used to remove lines for failed
translations, and remove these two columns.
- if ltlcross is used with --products=+5 instead of --products=5
then the stastics for each of the five products will be output
separately instead of being averaged.
- if ltlcross is used with tools that produce deterministic Streett
or Rabin automata (as specified with %D), then the statistics
output in CSV or JSON will have some extra columns to report
the size of these input automata before ltlcross converts them
into TGBA to perform its regular checks.
- ltlfilt, ltl2tgba, ltl2tgta, and ltlcross can now read formulas
from CSV files. Use option -F FILE/COL to read formulas from
column COL of FILE. Use -F FILE/-COL if the first line of
FILE be ignored.
- when ltlfilt processes formulas from a CSV file, it will output
each CSV line whose formula matches the given constraints, with
the rewriten formula. The new escape sequence %< (text in
columns before the formula) and %> (text after) can be used
with the --format option to alter this output.
- ltlfile, genltl, randltl, and ltl2tgba have a --csv-escape option
to help escape formulas in CSV files.
- Please check
http://spot.lip6.fr/userdoc/csv.html
for some discussion and examples of the last few features.
* Bug fixes:
- ltlcross' CSV output has been changed to be more RFC 4180
compliant: it no longuer output useless cosmetic spaces, and
use double-quotes with proper escaping for strings. The only
RFC 4180 rule that it does not follow is that it will terminate
lines with \n instead of \r\n because the latter cause issues
with a couple of tools.
- ltlcross failed to report missing input or output escape sequences
on all but the first configured translator.
--
Alexandre Duret-Lutz
I'm very pleased to announce the release of Spot 1.2.
Spot is a model-checking library developed collaboratively by LRDE
and LIP6. It provides algorithms and data structures to implement
the automata-theoretic approach to LTL model checking.
This release contains several new features (summarized below), but the
most notable are the interface with ltl2dstar (i.e., Spot can read
deterministic Rabin and Streett automata and convert them into Büchi
automata) and algorithms for minimizing deterministic TGBA or BA using
a SAT-solver.
You can find the new version here:
http://spot.lip6.fr/dl/spot-1.2.tar.gz
Please report any issue to <spot(a)lrde.epita.fr>.
New in spot 1.2 (2013-10-01)
* Changes to command-line tools:
- ltlcross has a new option --color to color its output. It is
enabled by default when the output is a terminal.
- ltlcross will give an example of infinite word accepted by the
two automata when the product between a positive automaton and a
negative automaton is non-empty.
- ltlcross can now read the Rabin and Streett automata output by
ltl2dstar. This type of output should be specified using '%D':
ltlcross 'ltl2dstar --ltl2nba=spin:path/to/ltl2tgba@-s %L %D'
However because Spot only supports Büchi acceptance, these Rabin
and Streett automata are immediately converted to TGBAs before
further processing by ltlcross. This is still interesting to
search for bugs in translators to Rabin or Streett automata, but
the statistics (of the resulting TGBAs) might not be very relevant.
- When ltlcross obtains a deterministic automaton from a
translator it will now complement this automaton to perform
additional intersection checks. This is complementation is done
only for deterministic automata (because that is cheap) and can
be disabled with --no-complement.
- To help with debugging problems detected by ltlcross, the
environment variables SPOT_TMPDIR and SPOT_TMPKEEP control where
temporary files are created and if they should be erased. Read
the man page of ltlcross for details.
- There is a new command, named dstar2tgba, that converts a
deterministic Rabin or Streett automaton (expressed in the
output format of ltl2dstar) into a TGBA, BA or Monitor.
In the case of Rabin acceptance, the conversion will output a
deterministic Büchi automaton if one such automaton exist. Even
if no such automaton exists, the conversion will actually
preserves the determinism of any SCC that can be kept
deterministic.
In the case of Streett acceptance, the conversion produces
non-deterministic Büchi automata with Generalized acceptance.
These are then degeneralized if requested.
See http://spot.lip6.fr/userdoc/dstar2tgba.html for some
examples, and the man page for more reference.
- The %S escape sequence used by ltl2tgba --stats to display the
number of SCCs in the output automaton has been renamed to %c.
This makes it more homogeneous with the --stats option of the
new dstar2tgba command.
Additionally, the %p escape can now be used to show whether the
output automaton is complete, and the %r escape will give the
number of seconds spent building the output automaton (excluding
the time spent parsing the input).
- ltl2tgba, ltl2tgta, and dstar2tgba have a --complete option
to output complete automata.
- ltl2tgba, ltl2tgta, and dstar2tgba can use a SAT-solver to
minimize deterministic automata. Doing so is only needed on
properties that are stronger than obligations (for obligations
our WDBA-minimization procedure will return a minimimal
deterministic automaton more efficiently) and is disabled by
default. See the spot-x(7) man page for documentation about the
related options: sat-minimize, sat-states, sat-acc, state-based.
See also http://spot.lip6.fr/userdoc/satmin.html for some
examples.
- ltlfilt, genltl, and randltl now have a --latex option to output
formulas in a way that its easier to embed in a LaTeX document.
Each operator is output as a command such as \U, \F, etc.
doc/tl/spotltl.sty gives one possible definition for each macro.
- ltlfilt, genltl, and randltl have a new --format option to
indicate how to present the output formula, possibly with
information about the input.
- ltlfilt as a new option, --relabel-bool, to abstract independent
Boolean subformulae as if they were atomic propositions.
For instance "a & GF(c | d) & b & X(c | d)" would be rewritten
as "p0 & GF(p1) & Xp1".
* New functions and classes in the library:
- dtba_sat_synthetize(): Use a SAT-solver to build an equivalent
deterministic TBA with a fixed number of states.
- dtba_sat_minimize(), dtba_sat_minimize_dichotomy(): Iterate
dtba_sat_synthetize() to reduce the number of states of a TBA.
- dtgba_sat_synthetize(), dtgba_sat_minimize(),
dtgba_sat_minimize_dichotomy(): Likewise, for deterministic TGBA.
- is_complete(): Check whether a TGBA is complete.
- tgba_complete(): Complete an automaton by adding a sink state
if needed.
- dtgba_complement(): Complement a deterministic TGBA.
- satsolver(): Run an (external) SAT solver, honoring the
SPOT_SATSOLVER environment variable if set.
- tba_determinize(): Run a power-set construction, and attempt
to fix the acceptance simulation to build a deterministic TBA.
- dstar_parse(): Read a Streett or Rabin automaton in
ltl2dstar's format. Note that this format allows only
deterministic automata.
- nra_to_nba(): Convert a (possibly non-deterministic) Rabin
automaton to a non-deterministic Büchi automaton.
- dra_to_ba(): Convert a deterministic Rabin automaton to a Büchi
automaton, preserving acceptance in all SCCs where this is possible.
- nsa_to_tgba(): Convert a (possibly non-deterministic) Streett
automaton to a non-deterministic TGBA.
- dstar_to_tgba(): Convert any automaton returned by dstar_parse()
into a TGBA.
- build_tgba_mask_keep(): Build a masked TGBA that shows only
a subset of states of another TGBA.
- build_tgba_mask_ignore(): Build a masked TGBA that ignore
a subset of states of another TGBA.
- class tgba_proxy: Helps writing on-the-fly algorithms that
delegate most of their methods to the original automaton.
- class bitvect: A dynamic bit vector implementation.
- class word: An infinite word, stored as prefix + cycle, with a
simplify() methods to simplify cycle and prefix in obvious ways.
- class temporary_file: A temporary file. Can be instanciated with
create_tmp_file() or create_open_tmpfile().
- count_state(): Return the number of states of a TGBA. Implement
a couple of specializations for classes where is can be know
without exploration.
- to_latex_string(): Output a formula using LaTeX syntax.
- relabel_bse(): Relabeling of Boolean Sub-Expressions.
Implements ltlfilt's --relabel-bool option describe above.
* Noteworthy internal changes:
- When minimize_obligation() is not given the formula associated
to the input automaton, but that automaton is deterministic, it
can still attempt to call minimize_wdba() and check the correcteness
using dtgba_complement(). This allows dstar2tgba to apply
WDBA-minimization on deterministic Rabin automata.
- tgba_reachable_iterator_depth_first has been redesigned to
effectively perform a DFS. As a consequence, it does not
inherit from tgba_reachable_iterator anymore.
- postproc::set_pref() was used to accept an argument among Any,
Small or Deterministic. These can now be combined with Complete
as Any|Complete, Small|Complete, or Deterministic|Complete.
- operands of n-ary operators (like & and |) are now ordered so
that Boolean terms come first. This speeds up syntactic
implication checks slightly. Also, literals are now sorted
using strverscmp(), so that p5 comes before p12.
- Syntactic implication checks have been generalized slightly
(for instance 'a & b & F(a & b)' is now reduced to 'a & b'
while it was not changed in previous versions).
- All the parsers implemented in Spot now use the same type to
store locations.
- Cleanup of exported symbols
All symbols in the library now have hidden visibility on ELF systems.
Public classes and functions have been marked explicitely for export
with the SPOT_API macro.
During this massive update, some of functions that should not have
been made public in the first place have been moved away so that
they can only be used from the library. Some old of unused
functions have been removed.
removed:
- class loopless_modular_mixed_radix_gray_code
hidden:
- class acc_compl
- class acceptance_convertor
- class bdd_allocator
- class free_list
* Bug fixes:
- Degeneralization was not indempotant on automata with an
accepting initial state that was on a cycle, but without
self-loop.
- Configuring with --enable-optimization would reset the value of
CXXFLAGS.
--
Alexandre Duret-Lutz
Spot 1.1.4 has been released.
This maintenance release fixes a couple of bugs reported over the
last weeks. These include a regression preventing 1.1.3 to parse
neverclaims produced by ltl2ba or ltl3ba, and a bug in the
interpretation of the closure of some SERE.
You can download the new release here:
http://spot.lip6.fr/dl/spot-1.1.4.tar.gz
New in spot 1.1.4 (2013-07-29)
* Bug fixes:
- The parser for neverclaim, updated in 1.1.3, would fail to
parse guards of the form (a) || (b) output by ltl2ba or
ltl3ba, and would only understand ((a) || (b)).
- When used from ltlcross, the same parser would fail to
parse further neverclaims after the first failure.
- Add a missing newline in some error message of ltlcross.
- Expressions like {SERE} were wrongly translated and simplified
for SEREs that accept the empty word: they were wrongly reduced
to true. Simplification and translation rules have been fixed,
and the doc/tl/tl.pdf specifications have been updated to better
explain that {SERE} has the semantics of a closure operator that
is not exactly what one could expect after reading the PSL
standard.
- Various typos.
--
Alexandre Duret-Lutz (off for three weeks)
I'm pleased to announce the release of Spot 1.1.3.
This maintenance release fixes a couple of bugs reported over the
last month, and add support for reading the new neverclaims output by
Spin 6.24+ (they can be parsed by ltlcross, for instance).
You can download the new release here:
http://spot.lip6.fr/dl/spot-1.1.3.tar.gz
New in spot 1.1.3 (2013-07-09)
* New feature:
- The neverclaim parser now understands the new style of output
used by Spin 6.24 and later.
* Bug fixes:
- The scc_filter() function could abort with a BDD error. If all
the acceptance sets of an SCC but the first one were useless.
- The script in bench/spin13/ would not work on MacOS X because
of some non-portable command.
- A memory corruption in ltlcross.
--
Alexandre Duret-Lutz
Spot 1.1.2 has been released.
This maintainance release fixes a couple minor bugs. If you have
version 1.1.1 already installed, there is no reason to upgrade unless
you are using ltlcross to generate statistics.
You can download the new release here:
http://spot.lip6.fr/dl/spot-1.1.2.tar.gz
New in spot 1.1.2 (2013-06-09)
* Bug fixes:
- Uninitialized variables in ltlcross (affect the count of terminal
weak, and strong SCCs).
- Workaround an old GCC bug to allow compilation with g++ <= 4.5
- Fix several Doxygen comments so that they display correctly.
--
Alexandre Duret-Lutz
This is to announce the release of Spot 1.1.1.
The main motivation for this release is to fix a bug introduced in
version 1.1 in the post-processing of (degeneralized) Büchi automata.
Although the NEWS excerpt at the end of this email shows several
new features, most of them are related to the discovery and fix of
this bug:
1) With this release, ltl2tgba --ba --lbtt has been changed to
output automata using the state-based acceptance flavor of
the LBTT format. This makes more sense when you work with
Büchi automata.
2) This lead to the discovery that previously, when --lbtt always
output automata with transition-based acceptance, there were
some rare formulas where ltl2tgba --ba --lbtt could output
automata that where not Büchi automata (although they had
the correct language), and worse: ltl2tgba --spin could
output an incorrect neverclaim.
3) fixing this required to reimplement two functions we started using
in 1.0 but that messed the structure of Büchi automata: namely
reverse simulation and SCC-based simplification of acceptance
condition.
Two small and easy options have also been added to ltlcross.
You can find the new release here:
http://spot.lip6.fr/dl/spot-1.1.1.tar.gz
A summary of the changes follows. Please report any issue
to <spot(a)lrde.epita.fr>.
New in spot 1.1.1 (2013-05-13):
* New features:
- lbtt_reachable(), the function that outputs a TGBA in LBTT's
format, has a new option to indicate that the TGBA being printed
is in fact a Büchi automaton. In this case it outputs an LBTT
automaton with state-based acceptance.
The output of the guards has also been changed in two ways:
1. atomic propositions that do not match p[0-9]+ are always
double-quoted. This avoids issues where t or f were used as
atomic propositions in the formula, output as-is in the
automaton, and read back as true or false. Other names that
correspond to LBT operators would cause problem as well.
2. formulas that label transitions are now output as
irredundant-sums-of-products.
- 'ltl2tgba --ba --lbtt' will now output automata with state-based
acceptance. You can use 'ltl2tgba --ba --lbtt=t' to force the
output of transition-based acceptance like in the previous
versions.
Some illustrations of this point and the previous one can be
found in the man page for ltl2tgba(1).
- There is a new function scc_filter_states() that removes all
useless states from a TGBA. It is actually an abbridged version
of scc_filter() that does not alter the acceptance conditions of
the automaton. scc_filter_state() should be used when
post-processing TGBAs that actually represent BAs.
- simulation_sba(), cosimulation_sba(), and
iterated_simulations_sba() are new functions that apply to TGBAs
that actually represent BAs. They preserve the imporant
property that if a state of the BA is is accepting, the outgoing
transitions of that state are all accepting in the TGBA that
represent the BA. This is something that was not preserved by
functions cosimultion() and iterated_simulations() as mentionned
in the bug fixes below.
- ltlcross has a new option --seed, that makes it possible to
change the seed used by the random graph generator.
- ltlcross has a new option --products=N to check the result of
each translation against N different state spaces, and everage
the statistics of these N products. N default to 1; larger
values increase the chances to detect inconsistencies in the
translations, and also make the average size of the product
built against the translated automata a more pertinent
statistic.
- bdd_dict::unregister_all_typed_variables() is a new function,
making it easy to unregister all BDD variables of a given type
owned by some object.
* Bug fixes:
- genltl --gh-r generated the wrong formulas due to a typo.
- ltlfilt --eventual and --universal were not handled properly.
- ltlfilt --stutter-invariant would trigger an assert on PSL formulas.
- ltl2tgba, ltl2tgta, ltlcross, and ltlfilt, would all choke on empty
lines in a file of formulas. They now ignore empty lines.
- The iterated simulation applied on degeneralized TGBA was bogus
for two reasons: one was that cosimulation was applied using the
generic cosimulation for TGBA, and the second is that
SCC-filtering, performed between iterations, was also a
TGBA-based algorithm. Both of these algorithms could lose the
property that if a TGBA represents a BA, all the outgoing
transitions of a state should be accepting. As a consequence, some
formulas where translated to incorrect Büchi automata.
--
Alexandre Duret-Lutz
We are pleased to announce the release of Spot 1.1.
Spot is a model-checking library developed collaboratively by LRDE
and LIP6. It provides algorithms and data structures to implement
the automata-theoretic approach to LTL model checking.
This release features several improvements developped with our
collegues from the Mazaryk University (also authors of the ltl3ba
translator) as detailed in the following paper:
Tomáš Babiak, Thomas Badie, Alexandre Duret-Lutz, Mojmír
Křetínský, Jan Strejček: Compositional Approach to Suspension and
Other Improvements to LTL Translation. To appear in the
proceedings of SPIN'13.
You can find the new release here:
http://spot.lip6.fr/dl/spot-1.1.tar.gz
A summary of the changes follows. Please report any issue
to <spot(a)lrde.epita.fr>.
New in spot 1.1 (2013-04-28):
* New features in the library:
- The postprocessor class now takes an optional option_map
argument that can be used to specify fine-tuning options, making
it easier to benchmark different scenarios while developing new
postprocessings.
- A new translator class implements a complete translation chain,
from LTL/PSL to TGBA/BA/Monitor. It performs pre- and
post-processings in addition to the core translation, and offers
an interface similar to that used in the postprocessor class, to
specify the intent of the translation.
- The degeneralization algorithm has learned three new tricks:
level reset, level caching, and SCC-based ordering. The former
two are enabled by default. Benchmarking has shown that the
latter one does not always have a positive effect, so it is
disabled by default. (See SPIN'13 paper.)
- The scc_filter() function, which removes dead SCCs and also
simplify acceptance conditions, has learnt how to simplify
acceptance conditions in a few tricky situations that were not
simplified previously. (See SPIN'13 paper.)
- An experimental "don't care" (direct) simulation has been
implemented. This simulations consider the acceptance
of out-of-SCC transitions as "don't care". It is not
enabled by default because it currently is very slow.
- remove_x() is a function that take a formula, and rewrite it
without the X operator. The rewriting is only correct for
stutter-insensitive LTL formulas (See K. Etessami's paper in IFP
vol. 75(6). 2000) This algorithm is accessible from the
command-line using ltlfilt's --remove-x option.
- is_stutter_insensitive() takes any LTL formula, and check
whether it is stutter-insensitive. This algorithm is accessible
from the command-line using ltlfilt's --stutter-insensitive
option.
- A new translation, called compsusp(), for "Compositional
Suspension" is implemented on top of ltl_to_tgba_fm().
(See SPIN'13 paper.)
- Some experimental LTL rewriting rules that trie to gather
suspendable formulas are implemented and can be activated
with the favor_event_univ option of ltl_simplifier. As
always please check doc/tl/tl.tex for the list of rules.
- Several functions have been introduced to check the
strength of an SCC.
is_inherently_weak_scc()
is_weak_scc()
is_syntactic_weak_scc()
is_complete_scc()
is_terminal_scc()
is_syntactic_terminal_scc()
Beware that the costly is_weak_scc() function introduced in Spot
1.0, which is based on a cycle enumeration, has been renammed to
is_inherently_weak_scc() to match established vocabulary.
* Command-line tools:
- ltl2tgba and ltl2tgta now honor a new --extra-options (or -x)
flag to fine-tune the algorithms used. The available options
are documented in the spot-x (7) manpage. For instance use '-x
comp-susp' to use the afore-mentioned compositional suspension.
- The output format of 'ltlcross --json' has been changed slightly.
In a future version we will offer some reporting script that turn
such JSON output into various tables and graphs, and these change
are required to make the format usable for other benchmarks (not
just ltlcross).
- ltlcross will now count the number of non-accepting, terminal,
weak, and strong SCCs, as well as the number of terminal, weak,
and strong automata produced by each tool.
* Documentation:
- org-mode files used to generate the documentation about
command-line tools (shown at http://spot.lip6.fr/userdoc/tools.html)
is distributed in doc/org/. The resulting html files are also
in doc/userdoc/.
* Bug fixes:
- There was a memory leak in the LTL simplification code, that could
only be triggered when disabling advanced simplifications.
- The translation of the PSL formula !{xxx} was incorrect when xxx
simplified to false.
- Various warnings triggered by new compilers.
--
Alexandre Duret-Lutz