NEWS 171 KB
Newer Older
1 2
New in spot 2.4.0.dev (not yet released)

3 4 5 6 7 8 9 10
  Tools:

  - genltl learned to generate 4 new families of formulas, taken
    from Müller & Sickert's GandALF'17 paper:
    --ms-example=RANGE     GF(a1&X(a2&X(a3&...)))&F(b1&F(b2&F(b3&...)))
    --ms-phi-h=RANGE       FG(a|b)|FG(!a|Xb)|FG(a|XXb)|FG(!a|XXXb)|...
    --ms-phi-r=RANGE       (FGa{n}&GFb{n})|((FGa{n-1}|GFb{n-1})&(...))
    --ms-phi-s=RANGE       (FGa{n}|GFb{n})&((FGa{n-1}&GFb{n-1})|(...))
11

12 13 14 15 16
  Library:

  - Rename three methods of spot::scc_info. New names are clearer. The
    old names have been deprecated.

17 18 19 20 21
  - The new function scc_info::states_on_acc_cycle_of() is able to
    return all states visited by any accepting cycles of the
    specified SCC. It must only be called on automata with a
    Streett-like acceptance condition.

22 23 24 25 26 27 28
  - The new function nsa_to_nca() is able to convert when possible an
    automaton with a Streett-like acceptance to an equivalent
    automaton with a co-Büchi acceptance. Actually the resulting
    automaton will always recognize at least the same language. It can
    recognize more if the original language can not be expressed with
    a co-Büchi acceptance condition.

29 30 31 32 33 34 35 36 37
  Deprecation notices:

  (These functions still work but compilers emit warnings.)

  - spot::scc_info::used_acc(), spot::scc_info::used_acc_of() and
    spot::scc_info::acc() are deprecated. They have been renamed
    spot::scc_info::marks(), spot::scc_info::marks_of() and
    spot::scc_info::acc_sets_of() respectively.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
38
New in spot 2.4 (2017-09-06)
39

40 41 42 43 44 45 46 47 48 49 50
  Build:

  - Spot is now built in C++14 mode, so you need at least GCC 5 or
    clang 3.4.  The current version of all major linux distributions
    ship with at least GCC 6, which defaults to C++14, so this should
    not be a problem.  In *this* release of Spot, most of the header
    files are still C++11 compatible, so you should be able to include
    Spot in a C++11 project in case you do not yet want to upgrade.
    There is also an --enable-c++17 option to configure in case you
    want to force a build of Spot in C++17 mode.

51 52
  Tools:

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
53 54 55 56 57 58 59 60
  - genaut is a new binary that produces families of automata defined
    in the literature (in the same way as we have genltl for LTL
    formulas).

  - autcross is a new binary that compares the output of tools
    transforming automata (in the same way as we have ltlcross for
    LTL translators).

61
  - genltl learned two generate two new families of formulas:
62 63 64 65 66 67
      --fxg-or=RANGE         F(p0 | XG(p1 | XG(p2 | ... XG(pn))))
      --gxf-and=RANGE        G(p0 & XF(p1 & XF(p2 & ... XF(pn))))
    The later is a generalization of --eh-pattern=9, for which a
    single state TGBA always exists (but previous version of Spot
    would build larger automata).

68
  - autfilt learned to build the union (--sum) or the intersection
Maximilien Colange's avatar
Typos  
Maximilien Colange committed
69 70
    (--sum-and) of two languages by putting two automata side-by-side
    and fiddling with the initial states.  This complements the already
71 72
    implemented intersection (--product) and union (--product-or),
    both based on a product.
73

74
  - autfilt learned to complement any alternating automaton with
75
    option --dualize.   (See spot::dualize() below.)
Thomas Medioni's avatar
Thomas Medioni committed
76

77 78 79 80
  - autfilt learned --split-edges to convert labels that are Boolean
    formulas into labels that are min-terms.  (See spot::split_edges()
    below.)

81 82 83
  - autfilt learned --simplify-acceptance to simplify some acceptance
    conditions.  (See spot::simplify_acceptance() below.)

84 85 86 87
  - autfilt --decompote-strength has been renamed to --decompose-scc
    because it can now extract the subautomaton leading to an SCC
    specified by number.  (The old name is still kept as an alias.)

88 89 90
  - The --stats=%c option of tools producing automata can now be
    restricted to count complete SCCs, using %[c]c.

91 92 93 94 95 96
  - Tools producing automata have a --stats=... option, and tools
    producing formulas have a --format=... option.  These two options
    work similarly, the use of different names is just historical.
    Starting with this release, all tools that recognize one of these
    two options also accept the other one as an alias.

97 98
  Library:

99 100
  - A new library, libspotgen, gathers all functions used to generate
    families of automata or LTL formulas, used by genltl and genaut.
101

102
  - spot::sum() and spot::sum_and() implements the union and the
103
    intersection of two automata by putting them side-by-side and
104
    using non-deterministim or universal branching on the initial
105
    state.
106

107 108 109
  - twa objects have a new property: prop_complete().  This obviously
    acts as a cache for the is_complete() function.

Maximilien Colange's avatar
Typos  
Maximilien Colange committed
110
  - spot::dualize() complements any alternating automaton.  Since
111 112 113
    the dual of a deterministic automaton is still deterministic, the
    function spot::dtwa_complement() has been deprecated and simply
    calls spot::dualize().
114

115 116 117 118 119 120
  - spot::decompose_strength() was extended and renamed to
    spot::decompose_scc() as it can now also extract a subautomaton
    leading to a particular SCC.  A demonstration of this feature via
    the Python bindings can be found at
    https://spot.lrde.epita.fr/ipynb/decompose.html

121 122
  - The print_dot() function will now display names for well known
    acceptance conditions under the formula when option 'a' is used.
123 124
    We plan to enable 'a' by default in a future release, so a new
    option 'A' has been added to hide the acceptance condition.
125

126 127 128 129 130
  - The print_dot() function has a new experimental option 'x' to
    output labels are LaTeX formulas.  This is meant to be used in
    conjunction with the dot2tex tool.  See
      https://spot.lrde.epita.fr/oaut.html#dot2tex

131 132 133 134
  - A new named property for automata called "original-states" can be
    used to record the origin of a state before transformation.  It is
    currently defined by the degeneralization algorithms, and by
    transform_accessible() and algorithms based on it (like
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
135 136 137 138 139
    remove_ap::strip(), decompose_scc()).  This is realy meant as an
    aid for writing algorithms that need this mapping, but it can also
    be used to debug these algorithms: the "original-states"
    information is displayed by the dot printer when the 'd' option is
    passed.  For instance in
140 141 142 143 144 145 146

      % ltl2tgba 'GF(a <-> Fb)' --dot=s
      % ltl2tgba 'GF(a <-> Fb)' | autfilt -B --dot=ds

    the second command outputs an automaton with states that show
    references to the first one.

147 148 149 150
  - A new named property for automata called "degen-levels" keeps track
    of the level of a state in a degeneralization. This information
    complements the one carried in "original-states".

151 152 153 154 155
  - A new named property for automata called "simulated-states" can be
    used to record the origin of a state through simulation. The
    behavior is similar to "original-states" above. Determinization
    takes advantage of this in its pretty print.

156 157 158 159 160 161
  - The new function spot::acc_cond::is_streett_like() checks whether
    an acceptance condition is conjunction of disjunctive clauses
    containing at most one Inf and at most one Fin.  It builds a
    vector of pairs to use if we want to assume the automaton has
    Streett acceptance.  The dual function is
    spot::acc_cond::is_rabin_like() works similarly.
162

163 164 165 166 167
  - The degeneralize() function has learned to consider acceptance
    marks common to all edges comming to a state to select its initial
    level.  A similar trick was already used in sbacc(), and saves a
    few states in some cases.

168 169 170 171 172 173 174
  - There is a new spot::split_edges() function that transforms edges
    (labeled by Boolean formulas over atomic propositions) into
    transitions (labeled by conjunctions where each atomic proposition
    appear either positive or negative).  This can be used to
    preprocess automata before feeding them to algorithms or tools
    that expect transitions labeled by letters.

175 176 177
  - spot::scc_info has two new methods to easily iterate over the
    edges of an SCC: edges_of() and inner_edges_of().

178 179 180
  - spot::scc_info can now be passed a filter function to ignore
    or cut some edges.

181 182 183 184 185
  - spot::scc_info now keeps track of acceptance sets that are common
    to all edges in an SCC.  These can be retrieved using
    scc_info::common_sets_of(scc), and they are used by scc_info to
    classify some SCCs as rejecting more easily.

186 187 188 189 190 191
  - The new function acc_code::remove() removes all the given
    acceptance sets from the acceptance condition.

  - It is now possible to change an automaton acceptance condition
    directly by calling twa::set_acceptance().

192 193 194 195 196
  - spot::cleanup_acceptance_here now takes an additional boolean
    parameter specifying whether to strip useless marks from the
    automaton.  This parameter is defaulted to true, in order to
    keep this modification backward-compatible.

197 198 199 200
  - The new function spot::simplify_acceptance() is able to perform
    some simplifications on an acceptance condition, and might lead
    to the removal of some acceptance sets.

201
  - The function spot::streett_to_generalized_buchi() is now able to
202
    work on automata with Streett-like acceptance.
203

204 205 206 207 208
  - The function for converting deterministic Rabin automata to
    deterministic Büchi automata (when possible), internal to the
    remove_fin() procedure, has been updated to work with
    transition-based acceptance and with Rabin-like acceptance.

209 210 211 212
  - spot::relabel_here() was used on automata to rename atomic
    propositions, it can now replace atomic propositions by Boolean
    subformula.  This makes it possible to use relabeling maps
    produced by relabel_bse() on formulas.
213

214 215 216 217
  - twa_graph::copy_state_names_from() can be used to copy the state
    names from another automaton, honoring "original-states" if
    present.

218 219
  - Building automata for LTL formula with a large number N of atomic
    propositions can be costly, because several loops and
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
220
    data-structures are exponential in N.  However a formula like
221 222 223 224 225 226 227 228
      ((a & b & c) | (d & e & f)) U ((d & e & f) | (g & h & i))
    can be translated more efficiently by first building an automaton
    for (p0 | p1) U (p1 | p2), and then substituting p0, p1, p2 by the
    appropriate Boolean formula.  Such a trick is now attempted
    for translation of formulas with 4 atomic propositions or
    more (this threshold can be changed, see -x relabel-bool=N in
    the spot-x(7) man page).

229 230 231 232
  - The LTL simplification routines learned that an LTL formula like
    G(a & XF(b & XFc & Fd) can be simplified to G(a & Fb & Fc & Fd),
    and dually F(a | XG(b | XGc | Gd)) = F(a | Gb | Gc | Gd).

233 234 235 236
    When working with SERE, the simplification of "expr[*0..1]" was
    improved.  E.g. {{a[*]|b}[*0..1]} becomes {a[*]|b} instead of
    {{a[+]|b}[*0..1]}.

237 238 239 240
  - The new function spot::to_weak_alternating() is able to take an
    input automaton with generalized Büchi/co-Büchi acceptance and
    convert it to a weak alternating automaton.

241 242
  - spot::sbacc() is can now also convert alternating automata
    to state-based acceptance.
243

244 245 246
  - spot::sbacc() and spot::degeneralize() learned to merge
    accepting sinks.

247
  - If the SPOT_BDD_TRACE environment variable is set, statistics
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
248 249
    about BDD garbage collection and table resizing are shown.

250
  - The & and | operators for acceptannce conditions have been changed
251
    slightly to be more symmetrical.  In older versions, operator &
252 253 254 255
    would move Fin() terms to the front, but that is not the case
    anymore.  Also operator & was already grouping all Inf() terms
    (for efficiency reasons), in this version operator | is
    symmetrically grouping all Fin() terms.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
256

257 258 259 260
  - The automaton parser is now reentrant, making it possible to
    process automata from different streams at the same time (i.e.,
    using multiple spot::automaton_stream_parser instances at once).

261 262 263 264 265 266 267 268 269
  - The print_hoa() and parse_automaton() functions have been updated
    to recognize the "exist-branch" property of the non-released HOA
    v1.1, as well as the new meaning of property "deterministic".  (In
    HOA v1 "properties: deterministic" means that the automaton has no
    existential branching; in HOA v1.1 it disallows universal
    branching as well.)  The meaning of "deterministic" in Spot has
    been adjusted to these new semantics, see "Backward-incompatible
    changes" below.

Maximilien Colange's avatar
Typos  
Maximilien Colange committed
270
  - The parser for HOA now recognizes and verifies correct use of the
271
    "univ-branch" property.  This is known to be a problem with option
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
272
    -H1 of ltl3ba 1.1.2 and ltl3dra 0.2.4, so the environment variable
273 274
    SPOT_HOA_TOLERANT can be set to disable the diagnostic.

275 276 277 278 279
  Python:

  - The 'spot.gen' package exports the functions from libspotgen.
    See https://spot.lrde.epita.fr/ipynb/gen.html for examples.

280 281 282 283
  Bugs fixed:

  - When the remove_fin() function was called on some automaton with
    Inf-less acceptance involving at least one disjunction (e.g.,
Maximilien Colange's avatar
Typos  
Maximilien Colange committed
284
    generalized co-Büchi), it would sometimes output an automaton with
285 286
    transition-based acceptance but marked as state-based.

287 288
  - The complete() function could complete an empty co-Büchi automaton
    into an automaton accepting everything.
289

290 291 292 293 294 295 296 297 298 299
  Backward-incompatible changes:

  - spot::acc_cond::mark_t::operator bool() has been marked as
    explicit.  The implicit converion to bool (and, via bool, to int)
    was a source of bugs.

  - spot::twa_graph::set_init_state(const state*) has been removed.
    It was never used.  You always want to use
    spot::twa_graph::set_init_state(unsigned) in practice.

300 301 302 303 304 305 306
  - The previous implementation of spot::is_deterministic() has been
    renamed to spot::is_universal().  The new version of
    spot::is_deterministic() requires the automaton to be both
    universal and existential.  This should not make any difference in
    existing code unless you work with the recently added support for
    alternating automata.

307 308 309
  - spot::acc_cond::mark_t::sets() now returns an internal iterable
    object instead of an std::vector<unsigned>.

310 311 312 313
  - The color palette optionally used by print_dot() has been extended
    from 9 to 16 colors.  While the first 8 colors are similar, they
    are a bit more saturated now.

314
  deprecation notices:
315

316
  (these functions still work but compilers emit warnings.)
317

318 319 320
  - spot::decompose_strength() is deprecated, it has been renamed
    to spot::decompose_scc().

321
  - spot::dtwa_complement() is deprecated.  prefer the more generic
322 323
    spot::dualize() instead.

324
  - the spot::twa::prop_deterministic() methods have been renamed to
325
    spot::twa::prop_universal() for consistency with the change to
326
    is_deterministic() listed above.  we have kept
327 328
    spot::twa::prop_deterministic() as a deprecated synonym for
    spot::twa::prop_universal() to help backward compatibility.
329

330
  - the spot::copy() function is deprecated.  use
331 332
    spot::make_twa_graph() instead.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
333
New in spot 2.3.5 (2017-06-22)
334

335 336
  Bugs fixed:

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
337
  - We have fixed new cases where translating multiple formulas in a
338 339
    single ltl2tgba run could produce automata different from those
    produced by individual runs.
340

341 342 343 344 345
  - The print_dot() function had a couple of issues when printing
    alternating automata: in particular, when using flag 's' (display
    SCC) or 'y' (split universal destination by colors) universal
    edges could be connected to undefined states.

346 347 348 349 350 351
  - Using --stats=%s or --stats=%s or --stats=%t could take an
    unnecessary long time on automata with many atomic propositions,
    due to a typo.  Furthermore, %s/%e/%t/%E/%T were printing
    a number of reachable states/edges/transitions, but %S was
    incorrectly counting all states even unreachable.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
352 353 354
  - Our verson of BuDDy had an incorrect optimization for the
    biimp operator.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
355
New in spot 2.3.4 (2017-05-11)
356

357 358
  Bugs fixed:

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
359
  - The transformation to state-based acceptance (spot::sbacc()) was
360
    incorrect on automata where the empty acceptance mark is accepting.
361

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
362
  - The --help output of randaut and ltl2tgba was showing an
363 364
    unsupported %b stat.

365 366 367
  - ltldo and ltlcross could leave temporary files behind when
    aborting on error.

368 369 370 371
  - The LTL simplifcation rule that turns F(f)|q into F(f|q)
    when q is a subformula that is both eventual and universal
    was documented but not applied in some forgotten cases.

372 373 374 375
  - Because of some caching inside of ltl2tgba, translating multiple
    formula in single ltl2tgba run could produce automata different
    from those produced by individual runs.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
376
New in spot 2.3.3 (2017-04-11)
377

378 379 380 381 382
  Tools:

  - ltldo and ltlcross learned shorthands to talk to ltl2da, ltl2dpa,
    and ltl2ldba (from Owl) without needing to specify %f>%O.

383
  - genltl learned --spec-patterns as an alias for --dac-patterns; it
384 385 386
    also learned two new sets of LTL formulas under --hkrss-patterns
    (a.k.a. --liberouter-patterns) and --p-patterns
    (a.k.a. --beem-patterns).
387

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
388
  Bugs fixed:
389

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
390 391
  - In "lenient" mode the formula parser would fail to recover from a
    missing closing brace.
392

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
393 394
  - The output of 'genltl --r-left=1 --r-right=1 --format=%F' had
    typos.
395

396 397 398 399
  - 'ltl2tgba Fa | autfilt --complement' would incorrectly claim that
    the output is "terminal" because dtwa_complement() failed to reset
    that property.

400 401 402
  - spot::twa_graph::purge_unreachable_states() was misbehaving on
    alternating automata.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
403 404
  - In bench/stutter/ the .cc files were not compiling due to warnings
    being caught as errors.
405

406 407 408 409 410 411
  - The code in charge of detecting DBA-type Rabin automata is
    actually written to handle a slightly larger class of acceptance
    conditions (e.g., Fin(0)|(Fin(1)&Inf(2))), however it failed to
    correctly detect DBA-typeness in some of these non-Rabin
    acceptance.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
412
New in spot 2.3.2 (2017-03-15)
413

414 415
  Tools:

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
416
  - In tools that output automata, the number of atomic propositions
417
    can be output using --stats=%x (output automaton) or --stats=%X
418
    (input automaton).  Additional options can be passed to list
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
419
    atomic propositions instead of counting them.  Tools that output
420
    formulas also support --format=%x for this purpose.
421

422 423
  Python:

424 425
  - The bdd_to_formula(), and to_generalized_buchi() functions can now
    be called in Python.
426

427 428 429 430 431
  Documentation:

  - https://spot.lrde.epita.fr/tut11.html is a new page describing
    how to build monitors in Shell, Python, or C++.

432 433 434 435 436
  Bugs fixed:

  - The tests using LTSmin's patched version of divine would fail
    if the current (non-patched) version of divine was installed.

437 438 439
  - Because of a typo, the output of --stats='...%P...' was correct
    only if %p was used as well.

440 441 442
  - genltl was never meant to have (randomly attributed) short
    options for --postive and --negative.

443 444 445 446
  - a typo in the code for transformating transition-based acceptance
    to state-based acceptance could cause a superfluous initial state
    to be output in some cases (the result was still correct).

447 448
  - 'ltl2tgba --any -C -M ...' would not complete automata.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
449
  - While not incorrect, the HOA properties output by 'ltl2tgba -M'
450 451 452 453
    could be 'inherently-weak' or 'terminal', while 'ltl2tgba -M -D'
    would always report 'weak' automata.  Both variants now report the
    most precise between 'weak' or 'terminal'.

454 455 456
  - spot::twa_graph::set_univ_init_state() could not be called with
    an initializer list.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
457
  - The Python wrappers for spot::twa_graph::state_from_number and
458 459
    spot::twa_graph::state_acc_sets were broken in 2.3.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
460
  - Instantiating an emptiness check on an automaton with unsupported
461 462 463 464
    acceptance condition should throw an exception.  This used to be
    just an assertion, disabled in release builds; the difference
    matters for the Python bindings.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
465
  Deprecation notice:
466 467 468 469

  - Using --format=%a to print the number of atomic propositions in
    ltlfilt, genltl, and randltl still works, but it is not documented
    anymore and should be replaced by the newly-introduced --format=%x
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
470 471
    for consistency with tools producing automata, where %a means
    something else.
472

473

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
474
New in spot 2.3.1 (2017-02-20)
475

476 477 478 479 480 481
  Tools:

  - ltldo learnt to act like a portfolio: --smallest and --greatest
    will select the best output automaton for each formula translated.
    See https://spot.lrde.epita.fr/ltldo.html#portfolio for examples.

482 483 484
  - The colors used in the output of ltlcross have been adjusted to
    work better with white backgrounds and black backgrounds.

485 486 487
  - The option (y) has been added to --dot. It splits the universal
    edges with the same targets but different colors.

488 489 490 491 492
  - genltl learnt three new families for formulas: --kr-n2=RANGE,
    --kr-nlogn=RANGE, and --kr-n=RANGE.  These formulas, from
    Kupferman & Rosenberg [MoChArt'10] are recognizable by
    deterministic Büchi automata with at least 2^2^n states.

493 494 495 496
  Library:

  - spot::twa_run::as_twa() has an option to preserve state names.

497 498 499 500
  - the method spot::twa::is_alternating(), introduced in Spot 2.3 was
    badly named and has been deprecated.  Use the negation of the new
    spot::twa::is_existential() instead.

501 502 503 504 505 506 507
  Bugs fixed:

  - spot::otf_product() was incorrectly registering atomic
    propositions.

  - spot::ltsmin_model::kripke() forgot to register the "dead"
    proposition.
508

509 510 511 512 513 514
  - The spot::acc_word type (used to construct acceptance condition)
    was using some non-standard anonymous struct.  It is unlikely that
    this type was actually used outside Spot, but if you do use it,
    spot::acc_word::op and spot::acc_word::type had to be renamed as
    spot::acc_word::sub.op and spot::acc_word::sub.type.

515 516 517
  - alternation_removal() was not always reporting the unsupported
    non-weak automata.

518 519 520 521
  - a long-standing typo in the configure code checking for Python
    caused any user-defined CPPFLAGS to be ignored while building
    Spot.

522 523 524 525
  - The display of clusters with universal edges was confused, because the
    intermediate node was not in the cluster even if one of the target was
    in the same one.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
526
New in spot 2.3 (2017-01-19)
527

528 529 530 531 532 533 534 535 536 537 538
  Build:

  * While Spot only relies on C++11 features, the configure script
    learned --enable-c++14 to compile in C++14 mode.  This allows us
    check that nothing breaks when we will switch to C++14.

  * Spot is now distributed with PicoSAT 965, and uses it for
    SAT-based minimization of automata without relying on temporary
    files.  It is still possible to use an external SAT solver by
    setting the SPOT_SATSOLVER environment variable.

539 540 541
  * The development Debian packages for Spot now install static
    libraries as well.

542 543
  * We now install configuration files for users of pkg-config.

544 545
  Tools:

546 547 548
  * ltlcross supports translators that output alternating automata in
    the HOA format.  Cross-comparison checks will only work with weak
    alternating automata (not necessarily *very* weak), but "ltlcross
549 550
    --no-check --product=0 --csv=..." will work with any alternating
    automaton if you just want satistics.
551

552 553 554 555 556 557
  * autfilt can read alternating automata.  This is still experimental
    (see below). Some of the algorithms proposed by autfilt will
    refuse to work because they have not yet been updated to work with
    alternating automata, but in any case they should display a
    diagnostic: if you see a crash, please report it.

558 559 560
  * autfilt has three new filters: --is-very-weak, --is-alternating,
    and --is-semi-deterministic.

561 562
  * the --check option of autfilt/ltl2tgba/ltldo/dstar2tgba can now
    take "semi-determinism" as argument.
563

564
  * autfilt --highlight-languages will color states that recognize
565
    identical languages.  (Only works for deterministic automata.)
566

567 568 569 570 571
  * 'autfilt --sat-minimize' and 'ltl2tgba -x sat-minimize' have
    undergone some backward incompatible changes.  They use binary
    search by default, and support different options than they used
    too.  See spot-x(7) for details.  The defaults are those that were
    best for the benchmark in bench/dtgbasat/.
572

573 574 575 576
  * ltlfilt learned --recurrence and --persistence to match formulas
    belonging to these two classes of the temporal hierarchy.  Unlike
    --syntactic-recurrence and --syntactic-persistence, the new checks
    are automata-based and will also match pathological formulas.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
577
    See https://spot.lrde.epita.fr/hierarchy.html
578

579
  * The --format option of ltlfilt/genltl/randltl/ltlgrind learned to
580
    print the class of a formula in the temporal hierarchy of Manna &
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
581
    Pnueli using %h.  See https://spot.lrde.epita.fr/hierarchy.html
582

583 584 585 586 587 588
  * ltldo and ltlcross learned a --relabel option to force the
    relabeling of atomic propositions to p0, p1, etc.  This is more
    useful with ltldo, as it allows calling a tool that restricts the
    atomic propositions it supports, and the output automaton will
    then be fixed to use the original atomic propositions.

589 590 591
  * ltldo and ltlcross have learned how to call ltl3hoa, so
    'ltl3hoa -f %f>%O' can be abbreviated to just 'ltl3hoa'.

592 593 594
  Library:

  * A twa is required to have at least one state, the initial state.
595 596
    An automaton can only be empty while it is being constructed,
    but should not be passed to other algorithms.
597

598
  * Couvreur's emptiness check has been rewritten to use the explicit
599 600
    interface when possible, to avoid overkill memory allocations.
    The new version has further optimizations for weak and terminal
601 602 603
    automata.  Overall, this new version is roughly 4x faster on
    explicit automata than the former one.  The old version has been
    kept for backward compatibility, but will be removed eventually.
604

605
  * The new version of the Couvreur emptiness check is now the default
606 607
    one, used by twa::is_empty() and twa::accepting_run().  Always
    prefer these functions over an explicit call to Couvreur.
608

609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626
  * experimental support for alternating automata:

    - twa_graph objects can now represent alternating automata.  Use
      twa_graph::new_univ_edge() and twa_graph::set_univ_init_state()
      to create universal edges an initial states; and use
      twa_graph::univ_dests() to iterate over the universal
      destinations of an edge.

    - the automaton parser will now read alternating automata in the
      HOA format.  The HOA and dot printers can output them.

    - the file twaalgos/alternation.hh contains a few algorithms
      specific to alternating automata:
      + remove_alternation() will transform *weak* alternating automata
        into TGBA.
      + the class outedge_combiner can be used to perform "and" and "or"
        on the outgoing edges of some alternating automaton.

627
    - scc_info has been adjusted to handle universal edges as if they
628 629 630
      were existential edges.  As a consequence, acceptance
      information is not accurate.

631 632 633 634 635 636 637
    - postprocessor will call remove_alternation() right away, so
      it can be used as a way to transform alternating automata
      into different sub-types of (generalized) Büchi automata.
      Note that although prostprocessor optimize the resulting
      automata, it still has no simplification algorithms that work
      at the alternating automaton level.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
638 639 640
    - See https://spot.lrde.epita.fr/tut23.html
      https://spot.lrde.epita.fr/tut24.html and
      https://spot.lrde.epita.fr/tut31.html for some code examples.
641

642 643 644 645
  * twa objects have two new properties, very-weak and
    semi-deterministic, that can be set or retrieved via
    twa::prop_very_weak()/twa::prop_semi_deterministic(), and that can
    be tested by is_very_weak_automaton()/is_semi_deterministic().
646

647 648 649 650 651 652
  * twa::prop_set has a new attribute used in twa::prop_copy() and
    twa::prop_keep() to indicate that determinism may be improved by
    an algorithm.  In other words properties like
    deterministic/semi-deterministic/unambiguous should be preserved
    only if they are positive.

653
  * language_map() and highlight_languages() are new functions that
654
    implement autfilt's --highlight-languages option mentionned above.
655

656
  * dtgba_sat_minimize_dichotomy() and dwba_sat_minimize_dichotomy()
657
    use language_map() to estimate a lower bound for binary search.
658

659
  * The encoding part of SAT-based minimization consumes less memory.
660

661 662 663 664
  * SAT-based minimization of automata can now be done using two
    incremental techniques that take a solved minimization and attempt
    to forbid the use of some states.  This is done either by adding
    clauses, or by using assumptions.
665

666 667 668 669
  * If the environment variable "SPOT_XCNF" is set during incremental
    SAT-based minimization, XCNF files suitable for the incremental SAT
    competition will be generated.  This requires the use of an exteral
    SAT solver, setup with "SPOT_SATSOLVER".  See spot-x(7).
670

671 672 673
  * The new function mp_class(f) returns the class of the formula
    f in the temporal hierarchy of Manna & Pnueli.

674 675 676 677 678 679 680 681 682
Python:

  * spot.show_mp_hierarchy() can be used to display the membership of
    a formula to the Manna & Pnueli hierarchy, in notebooks.  An
    example is in https://spot.lrde.epita.fr/ipynb/formulas.html

  * The on-line translator will now display the temporal hierarchy
    in the "Formula > property information" output.

683
Bugs fixed:
684 685 686 687 688 689 690 691

  * The minimize_wdba() function was not correctly minimizing automata
    with useless SCCs.  This was not an issue for the LTL translation
    (where useless SCCs are always removed first), but it was an issue
    when deciding if a formula was safety or guarantee.  As a
    consequence, some tricky safety or guarantee properties were only
    recognized as obligations.

692 693 694 695
  * When ltlcross was running a translator taking the Spin syntax as
    input (%s) it would not automatically relabel any unsupported
    atomic propositions as ltldo already do.

696 697 698 699
  * When running "autfilt --sat-minimize" on a automaton representing
    an obligation property, the result would always be a complete
    automaton even without the -C option.

700 701 702
  * ltlcross --products=0 --csv should not output any product-related
    column in the CSV output since it has nothing to display there.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
703
New in spot 2.2.2 (2016-12-16)
704

705 706 707 708 709
  Build:

  * If the system has an installed libltdl library, use it instead of
    the one we distribute.

710 711 712 713
  Bug fixes:

  * scc_filter() had a left-over print statement that would print
    "names" when copying the name of the states.
714

715 716 717 718 719
  * is_terminal() should reject automata that have accepting
    transitions going into rejecting SCCs.  The whole point of
    being a terminal automaton is that reaching an accepting
    transition guarantees that any suffix will be accepted.

720 721 722 723 724
  * The HOA parser incorrectly read "Acceptance: 1 Bar(0)" as a valid
    way to specify "Acceptance: 1 Fin(0)" because it assumed that
    everything that was not Inf was Fin.  These errors are now
    diagnosed.

725 726 727 728
  * Some of the installed headers (spot/misc/fixpool.hh,
    spot/misc/mspool.hh, spot/twaalgos/emptiness_stats.hh) were not
    self-contained.

729 730 731
  * ltlfilt --from-ltlf should ensure that "alive" holds initially in
    order to reject empty traces.

732 733 734
  * the on-line translator had a bug where a long ltl3ba process would
    continue running even after the script had timeout'ed.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
735
New in spot 2.2.1 (2016-11-21)
736

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
737
  Bug fix:
738

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
739 740
  * The bdd_noderesize() function, as modified in 2.2, would always
    crash.
741

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
742
New in spot 2.2 (2016-11-14)
743

744 745 746 747 748 749
  Command-line tools:

  * ltlfilt has a new option --from-ltlf to help reducing LTLf (i.e.,
    LTL over finite words) model checking to LTL model checking.  This
    is based on a transformation by De Giacomo & Vardi (IJCAI'13).

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
750 751 752 753
  * "ltldo --stats=%R", which used to display the serial number of the
    formula processed, was renamed to "ltldo --stats=%#" to free %R
    for the following feature.

754 755 756
  * autfilt, dstar2tgba, ltl2tgba, ltlcross, ltldo learned to measure
    cpu-time (as opposed to wall-time) using --stats=%R.  User or
    system time, for children or parent, can be measured separately by
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
757 758 759 760
    adding additional %[LETTER]R options.  The difference between %r
    (wall-clock time) and %R (CPU time) can also be used to detect
    unreliable measurements.  See
      https://spot.lrde.epita.fr/oaut.html#timing
761

762 763
  Library:

764 765 766
  * from_ltlf() is a new function implementing the --from-ltlf
    transformation described above.

767
  * is_unambiguous() was rewritten in a more efficient way.
768

769
  * scc_info learned to determine the acceptance of simple SCCs made
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
770
    of a single self-loop without resorting to remove_fin() for complex
771 772 773 774 775 776
    acceptance conditions.

  * remove_fin() has been improved to better deal with automata with
    "unclean" acceptance, i.e., acceptance sets that are declared but
    not used.  In particular, this helps scc_info to be more efficient
    at deciding the acceptance of SCCs in presence of Fin acceptance.
777

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
778 779
  * Simulation-based reductions now implement just bisimulation-based
    reductions on deterministic automata, to save time.  As an example,
780 781 782
    this halves the run time of
       genltl --rv-counter=10 | ltl2tgba

783 784
  * scc_filter() learned to preserve state names and highlighted states.

785 786 787 788 789
  * The BuDDy library has been slightly optimized: the initial setup
    of the unicity table can now be vectorized by GCC, and all calls
    to setjmp are now avoided when variable reordering is disabled
    (the default).

790 791 792 793 794 795 796 797
  * The twa class has three new methods:
      aut->intersects(other)
      aut->intersecting_run(other)
      aut->intersecting_word(other)
    currently these are just convenient wrappers around
      !otf_product(aut, other)->is_empty()
      otf_product(aut, other)->accepting_run()->project(aut)
      otf_product(aut, other)->accepting_word()
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
798 799 800
    with any Fin-acceptance removal performed before the product.
    However the plan is to implement these more efficiently in the
    future.
801

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
802
  Bug fixes:
803

804
  * ltl2tgba was always using the highest settings for the LTL
805 806 807 808
    simplifier, ignoring the --low and --medium options.  Now
      genltl --go-theta=12 | ltl2tgba --low --any
    is instantaneous as it should be.

809 810 811
  * The int-vector compression code could encode 6 and 22 in the
    same way, causing inevitable issues in our LTSmin interface.
    (This affects tests/ltsmin/modelcheck with option -z, not -Z.)
812

813 814 815
  * str_sere() and str_utf8_sere() were not returning the same
    string that print_sere() and print_utf8_sere() would print.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
816
  * Running the LTL parser in debug mode would crash.
817

818
  * tgba_determinize() could produce incorrect deterministic automata
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
819
    when run with use_simulation=true (the default) on non-simplified
820 821
    automata.

822 823
  * When the automaton_stream_parser reads an automaton from an
    already opened file descriptor, it will not close the file
824 825 826 827
    anymore.  Before that the spot.automata() python function used to
    close a file descriptor twice when reading from a pipe, and this
    led to crashes of the 0MQ library used by Jupyter, killing the
    Python kernel.
828

829 830 831
  * remove_fin() could produce incorrect result on incomplete
    automata tagged as weak and deterministic.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
832 833 834
  * calling set_acceptance() several times on an automaton could
    result in unexpected behaviors, because set_acceptance(0,...)
    used to set the state-based acceptance flag automatically.
835

836
  * Some buffering issue caused syntax errors to be displayed out
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
837
    of place by the on-line translator.
838

839
New in spot 2.1.2 (2016-10-14)
840

841 842 843 844 845 846
  Command-line tools:

  * genltl learned 5 new families of formulas
    (--tv-f1, --tv-f2, --tv-g1, --tv-g2, --tv-uu)
    defined in Tabakov & Vardi's RV'10 paper.

847 848 849 850 851 852
  * ltlcross's --csv and --json output was changed to not include
    information about the ambiguity or strength of the automata by
    default.   Computing those can be costly and not needed by
    every user, so it should now be requested explicitely using
    options --strength and --ambiguous.

853 854 855 856 857 858 859 860
  Library:

  * New LTL simplification rule:

    - GF(f & q) = G(F(f) & q) if q is
      purely universal and a pure eventuality.  In particular
      GF(f & GF(g)) now ultimately simplifies to G(F(f) & F(g)).

861 862
  Bug fixes:

863
  * Fix spurious uninitialized read reported by valgrind when
864
    is_Kleene_star() is compiled by clang++.
865

866
  * Using "ltlfilt some-large-file --some-costly-filter" could take
867 868 869 870 871 872 873
    to a lot of time before displaying the first results, because the
    output of ltlfilt is buffered: the buffer had to fill up before
    being flushed.  The issue did not manifest when the input is
    standard input, because of the C++ feature that reading std::cin
    should flush std::cout; however it was well visible when reading
    from files.  Flushing is now done more regularly.

874 875 876 877
  * Fix compilation warnings when -Wimplicit-fallthrough it enabled.

  * Fix python errors on Darwin when using methods from the spot module
    inside of the spot.ltsmin submodule.
878

879 880
  * Fix ltlcross crash when combining --no-check with --verbose.

881 882 883
  * Adjust paths and options used in bench/dtgbasat/ to match the
    changes introduced in Spot 2.0.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
884
New in spot 2.1.1 (2016-09-20)
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
885

886 887 888
  Command-line tools:

  * ltlfilt, randltl, genltl, and ltlgrind learned to display the size
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
889
    (%s), Boolean size (%b), and number of atomic propositions (%a)
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
890 891
    with the --format and --output options.  A typical use-case is to
    sort formulas by size:
892 893 894 895
       genltl --dac --format='%s,%f' | sort -n | cut -d, -f2
    or to group formulas by number of atomic propositions:
       genltl --dac --output='ap-%a.ltl'

896 897 898
  * autfilt --stats learned the missing %D, %N, %P, and %W sequences,
    to complete the existing %d, %n, %p, and %w.

899
  * The --stats %c option of ltl2tgba, autfilt, ltldo, and dstar2tgba
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
900
    now accepts options to filter the SCCs to count.  For instance
901 902 903
    --stats='%[awT]c' will count the SCCs that are (a)ccepting and
    (w)eak, but (not t)erminal.  See --help for all supported filters.

904 905 906
  Bugs fixed:

  * Fix several cases where command-line tools would fail to diagnose
907
    write errors (e.g. when writing to a filesystem that is full).
908
  * Typos in genltl --help and in the man page spot-x(7).
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
909

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
910
New in spot 2.1 (2016-08-08)
911

912 913
  Command-line tools:

914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939
  * All tools that input formulas or automata (i.e., autfilt,
    dstar2tgba, ltl2tgba, ltl2tgta, ltlcross, ltldo, ltlfilt,
    ltlgrind) now have a more homogeneous handling of the default
    input.

    - If no formula/automaton have been specified, and the standard
    input is a not a tty, then the default is to read that. This is a
    change for ltl2tgba and ltl2tgta.  In particular, it simplifies

        genltl --dac | ltl2tgba -F- | autfilt ...

    into

        genltl --dac | ltl2tgba | autfilt ...

    - If standard input is a tty and no other input has been
    specified, then an error message is printed.  This is a change for
    autfilt, dstar2tgba, ltlcross, ltldo, ltlfilt, ltlgrind, that used
    to expect the user to type formula or automata at the terminal,
    confusing people.

    - All tools now accept - as a shorthand for -F-, to force reading
    input from the standard input (regardless of whether it is a tty
    or not).  This is a change for ltl2tgba, ltl2tgta, ltlcross, and
    ltldo.

940 941 942
  * ltldo has a new option --errors=... to specify how to deal
    with errors from executed tools.

943 944
  * ltlcross and ltldo learned to bypass the shell when executing
    simple commands (with support for single or double-quoted
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962
    arguments, and redirection of stdin and stdout, but nothing more).

  * ltlcross and ltldo learned a new syntax to specify that an input
    formula should be written in some given syntax after rewriting
    some operators away.  For instance the defaults arguments passed
    to ltl2dstar have been changed from
         --output-format=hoa %L %O
    into
         --output-format=hoa %[WM]L %O
    where [WM] specifies that operators W and M should be rewritten
    away.  As a consequence running
         ltldo ltl2dstar -f 'a M b'
    will now work and call ltl2dstar on the equivalent formula
    'b U (a & b)' instead.  The operators that can be listed between
    brackets are the same as those of ltlfilt --unabbreviate option.

  * ltlcross learned to show some counterexamples when diagnosing
    failures of cross-comparison checks against random state spaces.
963

964 965
  * autfilt learned to filter automata by count of SCCs (--sccs=RANGE)
    or by type of SCCs (--accepting-sccs=RANGE,
966 967 968
    --rejecting-sccs=RANGE, trivial-sccs=RANGE, --terminal-sccs=RANGE,
    --weak-sccs=RANGE, --inherently-weak-sccs=RANGE).

969
  * autfilt learned --remove-unused-ap to remove atomic propositions
970 971
    that are declared in the input automaton, but not actually used.
    This of course makes sense only for input/output formats that
972
    declare atomic propositions (HOA & DSTAR).
973

974
  * autfilt learned two options to filter automata by count of used or
975 976 977 978
    unused atomic propositions: --used-ap=RANGE --unused-ap=RANGE.
    These differ from --ap=RANGE that only consider *declared* atomic
    propositions, regardless of whether they are actually used.

979 980
  * autfilt learned to filter automata by count of nondeterministsic
    states with --nondet-states=RANGE.
981

982
  * autfilt learned to filter automata representing stutter-invariant
983 984
    properties with --is-stutter-invariant.

985
  * autfilt learned two new options to highlight non-determinism:
986
    --highlight-nondet-states=NUM and --highlight-nondet-states=NUM
987 988
    where NUM is a color number.  Additionally --highlight-nondet=NUM is
    a shorthand for using the two.
989

990
  * autfilt learned to highlight a run matching a given word using the
991 992 993
    --highlight-word=[NUM,]WORD option.  However currently this only
    work on automata with Fin-less acceptance.

994 995 996
  * autfilt learned two options --generalized-rabin and
    --generalized-streett to convert the acceptance conditions.

997
  * genltl learned three new families: --dac-patterns=1..45,
998 999 1000
    --eh-patterns=1..12, and --sb-patterns=1..27.  Unlike other options
    these do not output scalable patterns, but simply a list of formulas
    appearing in these three papers: Dwyer et al (FMSP'98), Etessami &
1001
    Holzmann (Concur'00), Somenzi & Bloem (CAV'00).
1002

1003 1004
  * genltl learned two options, --positive and --negative, to control
    wether formulas should be output after negation or not (or both).
1005

1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018
  * The formater used by --format (for ltlfilt, ltlgrind, genltl,
    randltl) or --stats (for autfilt, dstar2tgba, ltl2tgba, ltldo,
    randaut) learned to recognize double-quoted fields and double the
    double-quotes output inbetween as expected from RFC4180-compliant
    CSV files.  For instance
      ltl2tgba -f 'a U "b+c"' --stats='"%f",%s'
    will output
      "a U ""b+c""",2

  * The --csv-escape option of genltl, ltlfilt, ltlgrind, and randltl
    is now deprecated.  The option is still here, but hidden and
    undocumented.

1019 1020
  * The --stats option of autfilt, dstar2tgba, ltl2tgba, ltldo,
    randaut learned to display the output (or input if that makes
1021
    sense) automaton as a HOA one-liner using %h (or %H), helping to
1022 1023
    create CSV files contained automata.

1024 1025 1026 1027
  * autfilt and dstar2tgba learned to read automata from columns in
    CSV files, specified using the same filename/COLUMN syntax used by
    tools reading formulas.

1028 1029 1030
  * Arguments passed to -x (in ltl2tgba, ltl2tgta, autfilt, dstar2tgba)
    that are not used are now reported as they might be typos.
    This ocurred a couple of times in our test-suite.  A similar
1031
    check is done for the arguments of autfilt --sat-minimize=...
1032

1033 1034 1035 1036 1037 1038 1039 1040 1041
  Library:

  * The print_hoa() function will now output version 1.1 of the HOA
    format when passed the "1.1" option (i.e., use -H1.1 from any
    command-line tool).  As far as Spot is concerned, this allows
    negated properties to be expressed.  Version 1 of the HOA format
    is still the default, but we plan to default to version 1.1 in the
    future.

1042 1043 1044 1045 1046 1047 1048
  * The "highlight-states" and "highlight-edges" named properties,
    which were introduced in 1.99.8, will now be output using
    "spot.highlight.edges:" and "spot.highlight.states:" headers if
    version 1.1 of the HOA format is selected.  The automaton parser
    was secretly able of reading that since 1.99.8, but that is now
    documented at https://spot.lrde.epita.fr/hoa.html#extensions

1049 1050 1051
  * highlight_nondet_states() and highlight_nondet_edges() are
    new functions that define the above two named properties.

1052
  * is_deterministic(), is_terminal(), is_weak(), and
1053 1054 1055
    is_inherently_weak(), count_nondet_states(),
    highlight_nondet_edges(), highlight_nondet_states() will update
    the corresponding properties of the automaton as a side-effect of
1056
    their check.
1057

1058 1059 1060 1061 1062 1063
  * the sbacc() function, used by "ltl2tgba -S" and "autfilt -S" to
    convert automata to state-based acceptance, learned some tricks
    (using SCCs, pulling accepting marks common to all outgoing edges,
    and pushing acceptance marks common to all incoming edges) to
    reduce the number of additional states needed.

1064 1065 1066 1067
  * to_generalized_rabin() and to_generalized_streett() are two new
    functions that convert the acceptance condition as requested
    without changing the transition structure.

1068 1069 1070
  * language_containment_checker now has default values for all
    parameters of its constructor.

1071 1072 1073 1074
  * spot::twa_run has a new method, project(), that can be used to
    project a run found in a product onto one of the original operand.
    This is for instance used by autfilt --highlight-word.

1075 1076 1077 1078
    The old spot::project_twa_run() function has been removed: it was
    not used anywhere in Spot, and had an obvious bug in its
    implementation, so it cannot be missed by anyone.

1079 1080
  * spot::twa has two new methods that supplement is_empty():
    twa::accepting_run() and twa::accepting_word().  They compute