NEWS 154 KB
Newer Older
1 2
New in spot 2.3.1.dev (not yet released)

3 4 5 6
  Tools:

  - In tools that output automata the number of atomic propositions
    can be output using --stats=%x (output automaton) or --stats=%X
7 8 9
    (input automaton).  Additional options can be passed to list
    atomic propositions instead of conting them.  Tools that output
    formulas also support --format=%x for this purpose.
10

11 12 13 14 15
  Documentation:

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

16 17 18 19 20
  Bugs fixed:

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

21 22 23
  - Because of a typo, the output of --stats='...%P...' was correct
    only if %p was used as well.

24 25 26
  - genltl was never meant to have (randomly attributed) short
    options for --postive and --negative.

27 28 29 30
  - 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).

31 32
  - 'ltl2tgba --any -C -M ...' would not complete automata.

33 34 35 36 37
  - while not incorrect, the HOA properties output by 'ltl2tgba -M'
    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'.

38 39 40
  - spot::twa_graph::set_univ_init_state() could not be called with
    an initializer list.

41 42 43
  - the Python wrappers for spot::twa_graph::state_from_number and
    spot::twa_graph::state_acc_sets were broken in 2.3.

44 45 46 47 48 49 50
  Deprecation notices:

  - 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
    for consistency with tools producing automata.

51 52 53 54 55 56
  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.

57 58 59 60
  - 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.

61

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
62
New in spot 2.3.1 (2017-02-20)
63

64 65 66 67 68 69
  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.

70 71 72
  - The colors used in the output of ltlcross have been adjusted to
    work better with white backgrounds and black backgrounds.

73 74 75
  - The option (y) has been added to --dot. It splits the universal
    edges with the same targets but different colors.

76 77 78 79 80
  - 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.

81 82 83 84 85
  - autfilt has a new transformation: --decompose-scc, which allows
    decomposition of automata through their accepting SCCs.
    A demonstration of this feature via the Python bindings
    can be found at https://spot.lrde.epita.fr/ipynb/decompose.html

86 87 88 89
  Library:

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

90 91 92 93
  - 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.

94 95 96 97 98 99 100
  Bugs fixed:

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

  - spot::ltsmin_model::kripke() forgot to register the "dead"
    proposition.
101

102 103 104 105 106 107
  - 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.

108 109 110
  - alternation_removal() was not always reporting the unsupported
    non-weak automata.

111 112 113 114
  - a long-standing typo in the configure code checking for Python
    caused any user-defined CPPFLAGS to be ignored while building
    Spot.

115 116 117 118
  - 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
119
New in spot 2.3 (2017-01-19)
120

121 122 123 124 125 126 127 128 129 130 131
  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.

132 133 134
  * The development Debian packages for Spot now install static
    libraries as well.

135 136
  * We now install configuration files for users of pkg-config.

137 138
  Tools:

139 140 141
  * 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
142 143
    --no-check --product=0 --csv=..." will work with any alternating
    automaton if you just want satistics.
144

145 146 147 148 149 150
  * 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.

151 152 153
  * autfilt has three new filters: --is-very-weak, --is-alternating,
    and --is-semi-deterministic.

154 155
  * the --check option of autfilt/ltl2tgba/ltldo/dstar2tgba can now
    take "semi-determinism" as argument.
156

157
  * autfilt --highlight-languages will color states that recognize
158
    identical languages.  (Only works for deterministic automata.)
159

160 161 162 163 164
  * '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/.
165

166 167 168 169
  * 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
170
    See https://spot.lrde.epita.fr/hierarchy.html
171

172
  * The --format option of ltlfilt/genltl/randltl/ltlgrind learned to
173
    print the class of a formula in the temporal hierarchy of Manna &
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
174
    Pnueli using %h.  See https://spot.lrde.epita.fr/hierarchy.html
175

176 177 178 179 180 181
  * 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.

182 183 184
  * ltldo and ltlcross have learned how to call ltl3hoa, so
    'ltl3hoa -f %f>%O' can be abbreviated to just 'ltl3hoa'.

185 186 187
  Library:

  * A twa is required to have at least one state, the initial state.
188 189
    An automaton can only be empty while it is being constructed,
    but should not be passed to other algorithms.
190

191
  * Couvreur's emptiness check has been rewritten to use the explicit
192 193
    interface when possible, to avoid overkill memory allocations.
    The new version has further optimizations for weak and terminal
194 195 196
    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.
197

198
  * The new version of the Couvreur emptiness check is now the default
199 200
    one, used by twa::is_empty() and twa::accepting_run().  Always
    prefer these functions over an explicit call to Couvreur.
201

202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219
  * 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.

220
    - scc_info has been adjusted to handle universal edges as if they
221 222 223
      were existential edges.  As a consequence, acceptance
      information is not accurate.

224 225 226 227 228 229 230
    - 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
231 232 233
    - 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.
234

235 236 237 238
  * 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().
239

240 241 242 243 244 245
  * 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.

246
  * language_map() and highlight_languages() are new functions that
247
    implement autfilt's --highlight-languages option mentionned above.
248

249
  * dtgba_sat_minimize_dichotomy() and dwba_sat_minimize_dichotomy()
250
    use language_map() to estimate a lower bound for binary search.
251

252
  * The encoding part of SAT-based minimization consumes less memory.
253

254 255 256 257
  * 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.
258

259 260 261 262
  * 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).
263

264 265 266
  * The new function mp_class(f) returns the class of the formula
    f in the temporal hierarchy of Manna & Pnueli.

267 268 269 270 271 272 273 274 275
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.

276
Bugs fixed:
277 278 279 280 281 282 283 284

  * 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.

285 286 287 288
  * 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.

289 290 291 292
  * 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.

293 294 295
  * 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
296
New in spot 2.2.2 (2016-12-16)
297

298 299 300 301 302
  Build:

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

303 304 305 306
  Bug fixes:

  * scc_filter() had a left-over print statement that would print
    "names" when copying the name of the states.
307

308 309 310 311 312
  * 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.

313 314 315 316 317
  * 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.

318 319 320 321
  * Some of the installed headers (spot/misc/fixpool.hh,
    spot/misc/mspool.hh, spot/twaalgos/emptiness_stats.hh) were not
    self-contained.

322 323 324
  * ltlfilt --from-ltlf should ensure that "alive" holds initially in
    order to reject empty traces.

325 326 327
  * 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
328
New in spot 2.2.1 (2016-11-21)
329

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
330
  Bug fix:
331

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
332 333
  * The bdd_noderesize() function, as modified in 2.2, would always
    crash.
334

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
335
New in spot 2.2 (2016-11-14)
336

337 338 339 340 341 342
  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
343 344 345 346
  * "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.

347 348 349
  * 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
350 351 352 353
    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
354

355 356
  Library:

357 358 359
  * from_ltlf() is a new function implementing the --from-ltlf
    transformation described above.

360
  * is_unambiguous() was rewritten in a more efficient way.
361

362
  * scc_info learned to determine the acceptance of simple SCCs made
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
363
    of a single self-loop without resorting to remove_fin() for complex
364 365 366 367 368 369
    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.
370

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
371 372
  * Simulation-based reductions now implement just bisimulation-based
    reductions on deterministic automata, to save time.  As an example,
373 374 375
    this halves the run time of
       genltl --rv-counter=10 | ltl2tgba

376 377
  * scc_filter() learned to preserve state names and highlighted states.

378 379 380 381 382
  * 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).

383 384 385 386 387 388 389 390
  * 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
391 392 393
    with any Fin-acceptance removal performed before the product.
    However the plan is to implement these more efficiently in the
    future.
394

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
395
  Bug fixes:
396

397
  * ltl2tgba was always using the highest settings for the LTL
398 399 400 401
    simplifier, ignoring the --low and --medium options.  Now
      genltl --go-theta=12 | ltl2tgba --low --any
    is instantaneous as it should be.

402 403 404
  * 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.)
405

406 407 408
  * 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
409
  * Running the LTL parser in debug mode would crash.
410

411
  * tgba_determinize() could produce incorrect deterministic automata
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
412
    when run with use_simulation=true (the default) on non-simplified
413 414
    automata.

415 416
  * When the automaton_stream_parser reads an automaton from an
    already opened file descriptor, it will not close the file
417 418 419 420
    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.
421

422 423 424
  * remove_fin() could produce incorrect result on incomplete
    automata tagged as weak and deterministic.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
425 426 427
  * 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.
428

429
  * Some buffering issue caused syntax errors to be displayed out
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
430
    of place by the on-line translator.
431

432
New in spot 2.1.2 (2016-10-14)
433

434 435 436 437 438 439
  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.

440 441 442 443 444 445
  * 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.

446 447 448 449 450 451 452 453
  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)).

454 455
  Bug fixes:

456
  * Fix spurious uninitialized read reported by valgrind when
457
    is_Kleene_star() is compiled by clang++.
458

459
  * Using "ltlfilt some-large-file --some-costly-filter" could take
460 461 462 463 464 465 466
    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.

467 468 469 470
  * 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.
471

472 473
  * Fix ltlcross crash when combining --no-check with --verbose.

474 475 476
  * 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
477
New in spot 2.1.1 (2016-09-20)
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
478

479 480 481
  Command-line tools:

  * ltlfilt, randltl, genltl, and ltlgrind learned to display the size
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
482
    (%s), Boolean size (%b), and number of atomic propositions (%a)
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
483 484
    with the --format and --output options.  A typical use-case is to
    sort formulas by size:
485 486 487 488
       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'

489 490 491
  * autfilt --stats learned the missing %D, %N, %P, and %W sequences,
    to complete the existing %d, %n, %p, and %w.

492
  * The --stats %c option of ltl2tgba, autfilt, ltldo, and dstar2tgba
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
493
    now accepts options to filter the SCCs to count.  For instance
494 495 496
    --stats='%[awT]c' will count the SCCs that are (a)ccepting and
    (w)eak, but (not t)erminal.  See --help for all supported filters.

497 498 499
  Bugs fixed:

  * Fix several cases where command-line tools would fail to diagnose
500
    write errors (e.g. when writing to a filesystem that is full).
501
  * Typos in genltl --help and in the man page spot-x(7).
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
502

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
503
New in spot 2.1 (2016-08-08)
504

505 506
  Command-line tools:

507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532
  * 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.

533 534 535
  * ltldo has a new option --errors=... to specify how to deal
    with errors from executed tools.

536 537
  * ltlcross and ltldo learned to bypass the shell when executing
    simple commands (with support for single or double-quoted
538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555
    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.
556

557 558
  * autfilt learned to filter automata by count of SCCs (--sccs=RANGE)
    or by type of SCCs (--accepting-sccs=RANGE,
559 560 561
    --rejecting-sccs=RANGE, trivial-sccs=RANGE, --terminal-sccs=RANGE,
    --weak-sccs=RANGE, --inherently-weak-sccs=RANGE).

562
  * autfilt learned --remove-unused-ap to remove atomic propositions
563 564
    that are declared in the input automaton, but not actually used.
    This of course makes sense only for input/output formats that
565
    declare atomic propositions (HOA & DSTAR).
566

567
  * autfilt learned two options to filter automata by count of used or
568 569 570 571
    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.

572 573
  * autfilt learned to filter automata by count of nondeterministsic
    states with --nondet-states=RANGE.
574

575
  * autfilt learned to filter automata representing stutter-invariant
576 577
    properties with --is-stutter-invariant.

578
  * autfilt learned two new options to highlight non-determinism:
579
    --highlight-nondet-states=NUM and --highlight-nondet-states=NUM
580 581
    where NUM is a color number.  Additionally --highlight-nondet=NUM is
    a shorthand for using the two.
582

583
  * autfilt learned to highlight a run matching a given word using the
584 585 586
    --highlight-word=[NUM,]WORD option.  However currently this only
    work on automata with Fin-less acceptance.

587 588 589
  * autfilt learned two options --generalized-rabin and
    --generalized-streett to convert the acceptance conditions.

590
  * genltl learned three new families: --dac-patterns=1..45,
591 592 593
    --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 &
594
    Holzmann (Concur'00), Somenzi & Bloem (CAV'00).
595

596 597
  * genltl learned two options, --positive and --negative, to control
    wether formulas should be output after negation or not (or both).
598

599 600 601 602 603 604 605 606 607 608 609 610 611
  * 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.

612 613
  * The --stats option of autfilt, dstar2tgba, ltl2tgba, ltldo,
    randaut learned to display the output (or input if that makes
614
    sense) automaton as a HOA one-liner using %h (or %H), helping to
615 616
    create CSV files contained automata.

617 618 619 620
  * autfilt and dstar2tgba learned to read automata from columns in
    CSV files, specified using the same filename/COLUMN syntax used by
    tools reading formulas.

621 622 623
  * 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
624
    check is done for the arguments of autfilt --sat-minimize=...
625

626 627 628 629 630 631 632 633 634
  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.

635 636 637 638 639 640 641
  * 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

642 643 644
  * highlight_nondet_states() and highlight_nondet_edges() are
    new functions that define the above two named properties.

645
  * is_deterministic(), is_terminal(), is_weak(), and
646 647 648
    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
649
    their check.
650

651 652 653 654 655 656
  * 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.

657 658 659 660
  * to_generalized_rabin() and to_generalized_streett() are two new
    functions that convert the acceptance condition as requested
    without changing the transition structure.

661 662 663
  * language_containment_checker now has default values for all
    parameters of its constructor.

664 665 666 667
  * 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.

668 669 670 671
    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.

672 673
  * spot::twa has two new methods that supplement is_empty():
    twa::accepting_run() and twa::accepting_word().  They compute
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
674
    what their names suggest.  Note that twa::accepting_run(), unlike
675 676 677
    the two others, is currently restricted to automata with Fin-less
    acceptance.

678 679 680 681 682
  * spot::check_stutter_invariance() can now work on non-deterministic
    automata for which no corresponding formula is known.  This
    implies that "autfilt --check=stutter" will now label all
    automata, not just deterministic automata.

683
  * New LTL and PSL simplification rules:
684 685
    - if e is pure eventuality and g => e, then e U g = Fg
    - if u is purely universal and u => g, then u R g = Gg
686 687
    - {s[*0..j]}[]->b = {s[*1..j]}[]->b
    - {s[*0..j]}<>->b = {s[*1..j]}<>->b
688

689 690 691 692
  * spot::twa::succ_iterable renamed to
    spot::internal::twa_succ_iterable to make it clear this is not for
    public consumption.

693 694 695 696 697
  * spot::fair_kripke::state_acceptance_conditions() renamed to
    spot::fair_kripke::state_acceptance_mark() for consistency.  This
    is backward incompatible, but we are not aware of any actual use
    of this method.

698 699
  Python:

700
  * The __format__() method for formula supports the same
701 702 703 704
    operator-rewritting feature introduced in ltldo and ltlcross.
    So "{:[i]s}".format(f) is the same as
    "{:s}".format(f.unabbreviate("i")).

705 706
  * Bindings for language_containment_checker were added.

707 708
  * Bindings for randomize() were added.

709 710 711
  * Iterating over edges via "aut.out(s)" or "aut.edges()"
    now allows modifying the edge fields.

712
  * Under IPython the spot.ltsmin module now offers a
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
713
    %%pml magic to define promela models, compile them
714 715 716
    with spins, and dynamically load them.   This is
    akin to the %%dve magic that was already supported.

717 718 719 720
  * The %%dve and %%pml magics honor the SPOT_TMPDIR and
    TMPDIR environment variables.  This especially helps
    when the current directory is read-only.

721 722 723 724
  Documentation:

  * A new example page shows how to test the equivalence of
    two LTL/PSL formulas.  https://spot.lrde.epita.fr/tut04.html
725

726 727
  * A new page discusses explicit vs. on-the-fly interfaces for
    exploring automata in C++.  https://spot.lrde.epita.fr/tut50.html
728

729
  * Another new page shows how to implement an on-the-fly Kripke
730
    structure for a custom state space.
731 732
    https://spot.lrde.epita.fr/tut51.html

733 734
  * The concepts.html page now lists all named properties
    used by automata.
735

736 737 738 739 740 741
  Bug fixes:

  * When ltlcross found a bug using a product of complemented
    automata, the error message would report "Comp(Ni)*Comp(Pj)" as
    non-empty while the actual culprit was "Comp(Nj)*Comp(Pi)".

742 743 744
  * Fix some non-deterministic execution of minimize_wdba(), causing
    test-suite failures with the future G++ 7, and clang 3.9.

745 746 747
  * print_lbtt() had a memory leak when printing states without
    successors.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
748
New in spot 2.0.3 (2016-07-11)
749

750 751 752 753 754
  Bug fixes:

  * The degen-lcache=1 option of the degeneralization algorithm (which
    is a default option) did not behave exactly as documented: instead
    of reusing the first level ever created for a state where the
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
755 756
    choice of the level is free, it reused the last level ever used.
    This caused some posterior simulation-based reductions to be less
757
    efficient at reducing automata (on the average).
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
758
  * The generalized testing automata displayed by the online
759
    translator were incorrect (those output by ltl2tgta were OK).
760
  * ltl2tgta should not offer options --ba, --monitor, --tgba and such.
761
  * the relabel() function could incorrectly unregister old atomic
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
762 763 764
    propositions even when they were still used in the output (e.g.,
    if a&p0 is relabeled to p0&p1).  This could cause ltldo and the
    online translator to report errors.
765

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
766 767 768 769 770 771 772 773
New in spot 2.0.2 (2016-06-17)

  Documentation:

  * We now have a citing page at https://spot.lrde.epita.fr/citing.html
    providing a list of references about Spot.
  * The Python examples have been augmented with the two examples
    from our ATVA'16 tool paper.
774

775 776 777 778
  Bug fixes:

  * Fix compilation error observed with Clang++ 3.7.1 and GCC 6.1.1
    headers.
779
  * Fix an infinite recursion in relabel_bse().
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
780
  * Various small typos and cosmetic cleanups.
781

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
782
New in spot 2.0.1 (2016-05-09)
783

784 785
  Library:

786
  * twa::unregister_ap() and twa_graph::remove_unused_ap() are new
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
787
    methods introduced to fix some of the bugs listed below.
788

789 790 791 792 793
  Documentation:

  * Add missing documentation for the option string passed to
    spot::make_emptiness_check_instantiator().

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
794
  * There is now a spot(7) man page listing all installed
795 796
    command-line tools.

797 798 799 800
  Python:

  * The tgba_determinize() function is now accessible in Python.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
801 802
  Bug fixes:

803
  * The automaton parser would choke on comments like /******/.
804
  * check_strength() should also set negated properties.
805 806 807
  * Fix autfilt to apply --simplify-exclusive-ap only after
    the simplifications of (--small/--deterministic) have
    been performed.
808 809
  * The automaton parser did not fully register atomic propositions
    for automata read from never claim or as LBTT.
810
  * spot::ltsmin::kripke() had the same issue.
811 812 813 814
  * The sub_stats_reachable() function used to count the number
    of transitions based on the number of atomic propositions
    actually *used* by the automaton instead of using the number
    of AP declared.
815 816 817 818 819
  * print_hoa() will now output all the atomic propositions that have
    been registered, not only those that are used in the automaton.
    (Note that it will also throw an exception if the automaton uses
    an unregistered AP; this is how some of the above bugs were
    found.)
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
820
  * For Small or Deterministic preference, the postprocessor
821 822 823
    will now unregister atomic propositions that are no longer
    used in labels.   Simplification of exclusive properties
    and remove_ap::strip() will do similarly.
824 825
  * bench/ltl2tgba/ was not working since the source code
    reorganization of 1.99.7.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
826
  * Various typos and minor documentation fixes.
827

828

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
829
New in spot 2.0 (2016-04-11)
830

831 832 833
  Command-line tools:

  * ltlfilt now also support the --accept-word=WORD and
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
834 835
    --reject-word=WORD options that were introduced in autfilt in the
    previous version.
836

837 838 839
  Python:

  * The output of spot.atomic_prop_collect() is printable and
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
840
    can now be passed directly to spot.ltsmin.model.kripke().
841

842 843 844 845
  Library:

  * digraph::valid_trans() renamed to digraph::is_valid_edge().

846 847
  Documentation:

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
848 849 850 851 852
  * The concepts page (https://spot.lrde.epita.fr/concepts.html) now
    includes a highlevel description of the architecture, and some
    notes aboute automata properties.

  * More Doxygen documentation for spot::formula and spot::digraph.
853

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
854
New in spot 1.99.9 (2016-03-14)
855

856 857
  Command-line tools:

858 859 860
  * autfilt has two new options: --accept-word=WORD and
    --reject-word=WORD for filtering automata that accept or reject
    some word.  The option may be used multiple times.
861

862 863
  Library:

864 865 866
  * The parse_word() function can be used to parse a lasso-shaped
    word and build a twa_word.  The twa_word::as_automaton()
    method can be used to create an automaton out of that.
867
  * twa::ap_var() renamed to twa::ap_vars().
868 869 870 871
  * emptiness_check_instantiator::min_acceptance_conditions() and
    emptiness_check_instantiator::max_acceptance_conditions() renamed
    to emptiness_check_instantiator::min_sets() and
    emptiness_check_instantiator::max_sets().
872 873
  * tgba_reachable_iterator (and subclasses) was renamed to
    twa_reachable_iterator for consistency.
874

875 876 877 878
  Documentation:

  * The page https://spot.lrde.epita.fr/upgrade2.html should help
    people migrating old C++ code written for Spot 1.2.x, and update
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
879
    it for (the upcoming) Spot 2.0.
880

881 882 883 884
  Bug fixes:

  * spot/twaalgos/gtec/gtec.hh was incorrectly installed as
  spot/tgbaalgos/gtec/gtec.hh.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
885
  * The shared libraries should now compile again on Darwin.
886

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
887
New in spot 1.99.8 (2016-02-18)
888

889 890
  Command-line tools:

891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917
  * ltl2tgba now also support the --generic option (already supported
    by ltldo and autfilt) to lift any restriction on the acceptance
    condition produced.  This option now has a short version: -G.

  * ltl2tgba and autfilt have learnt how to determinize automata.
    For this to work, --generic acceptance should be enabled (this
    is the default for autfilt, but not for ltl2tgba).

    "ltl2tgba -G -D" will now always outpout a deterministic automaton.
    It can be an automaton with transition-based parity acceptance in
    case Spot could not find a deterministic automaton with (maybe
    generalized) Büchi acceptance.

    "ltl2tgba -D" is unchanged (the --tgba acceptance is the default),
    and will output a deterministic automaton with (generalized) Büchi
    acceptance only if one could be found.  Otherwise a
    non-deterministic automaton is output, but this does NOT mean that
    no deterministic Büchi automaton exist for this formula.  It only
    means Spot could not find it.

    "autfilt -D" will determinize any automaton, because --generic
    acceptance is the default for autfilt.

    "autfilt -D --tgba" will behave like "ltl2tgba -D", i.e., it may
    fail to find a deterministic automaton (even if one exists) and
    return a nondeterministic automaton.

918 919 920 921 922
  * "autfilt --complement" now also works for non-deterministic
    automata but will output a deterministic automaton.
    "autfilt --complement --tgba" will likely output a
    nondeterministic TGBA.

923 924 925
  * autfilt has a new option, --included-in, to filter automata whose
    language are included in the language of a given automaton.

926 927 928
  * autfilt has a new option, --equivalent-to, to filter automata
    that are equivalent (language-wise) to a given automaton.

929 930 931 932 933 934 935
  * ltlcross has a new option --determinize to instruct it to
    complement non-deterministic automata via determinization.  This
    option is not enabled by default as it can potentially be slow and
    generate large automata.  When --determinize is given, option
    --product=0 is implied, since the tests based on products with
    random state-space are pointless for deterministic automata.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
936 937 938
  * ltl2tgba and ltldo now support %< and %> in the string passed
    to --stats when reading formulas from a CSV file.

939 940 941 942 943
  * ltlfilt's option --size-min=N, --size-max=N, --bsize-min=N, and
    --bsize-max=N have been reimplemented as --size=RANGE and
    --bsize=RANGE.  The old names are still supported for backward
    compatibility, but they are not documented anymore.

944 945
  * ltlfilt's option --ap=N can now take a RANGE as parameter.

946 947 948
  * autfilt now has a --ap=RANGE option to filter automata by number
    of atomic propositions.

949 950 951 952 953
  Library:

  * Building products with different dictionaries now raise an
    exception instead of using an assertion that could be disabled.

954
  * The load_ltsmin() function has been split in two.  Now you should
955
    first call ltsmin_model::load(filename) to create an ltsmin_model,
956
    and then call the ltsmin_model::kripke(...) method to create an
957 958 959
    automaton that can be iterated on the fly.  The intermediate
    object can be queried about the supported variables and their
    types.
960

961 962 963 964 965 966 967 968 969 970 971 972
  * print_dot() now accepts several new options:
    - use "<N" to specify a maximum number of states to output.
      Incomplete states are then marked appropriately.  For a quick
      example, compare
	ltl2tgba -D 'Ga | Gb | Gc' -d'<3'
      with
        ltl2tgba -D 'Ga | Gb | Gc' -d
    - use "C(color)" to specify the color to use for filling states.
    - use "#" to display the internal number of each transition
    - use "k" to use state-based labels when possible.  This is
      similar to the "k" option already supported by print_hoa(), and
      is useful when printing Kripke structures.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
973

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
974 975
  * Option "k" is automatically used by print_dot() and print_hoa()
    when printing Kripke structures.
976

977 978 979 980
  * print_dot() also honnor two new automaton properties called
    "highlight-edges" and "highlight-states".  These are used to color
    a subset of edges or transitions.

981 982 983 984
  * There is a new tgba_determinize() function.  Despite its name, it
    in facts works on transition-based Büchi automaton, and will first
    degeneralize any automaton with generalized Büchi acceptance.

985 986 987
  * The twa_safra_complement class has been removed.  Use
    tgba_determinize() and dtwa_complement() instead.

988 989
  * The twa::transition_annotation() and
    twa::compute_support_conditions() methods have been removed.
990

991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016
  * The interface for all functions parsing formulas (LTL, PSL, SERE,
    etc.) has been changed to use an interface similar to the one used
    for parsing automata.  These function now return a parsed_formula
    object that includes both a formula and a list of syntax errors.

    Typically a function written as

       spot::formula read(std::string input)
       {
	  spot::parse_error_list pel;
	  spot::formula f = spot::parse_infix_psl(input, pel);
	  if (spot::format_parse_errors(std::cerr, input, pel))
	    exit(2);
	  return f;
       }

    should be updated to

       spot::formula read(std::string input)
       {
	  spot::parsed_formula pf = spot::parse_infix_psl(input);
	  if (pf.format_errors(std::cerr))
	    exit(2);
	  return pf.f;
       }

1017 1018
  Python:

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1019 1020 1021
  * The ltsmin interface has been binded in Python.  It also
    comes with a %%dve cell magic to edit DiVinE models in the notebook.
    See https://spot.lrde.epita.fr/ipynb/ltsmin.html for a short example.
1022

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1023 1024 1025 1026 1027
  * spot.setup() sets de maximum number of states to display in
    automata to 50 by default, as more states is likely to be
    unreadable (and slow to process by GraphViz).  This can be
    overridden by calling spot.setup(max_states=N).

1028 1029 1030 1031
  * Automata now have methods to color selected states and
    transitions.  See
    https://spot.lrde.epita.fr/ipynb/highlighting.html for an example.

1032 1033 1034 1035 1036
  Documentation:

  * There is a new page giving informal illustrations (and extra
    pointers) for some concepts used in Spot.
    See https://spot.lrde.epita.fr/concepts.html
1037

1038
  Bug fixes:
1039 1040 1041

  * Using ltl2tgba -U would fail to output the unambiguous property
    (regression introduced in 1.99.7)
1042 1043
  * ltlfilt, autfilt, randltl, and randaut could easily crash when
    compiled statically (i.e., with configure --disable-shared).
1044
  * "1 U (a | Fb)" was not always simplified to "F(a | b)".
1045 1046
  * destroying the operands of an otf_product() before the product
    itself could crash.
1047

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1048
New in spot 1.99.7 (2016-01-15)
1049 1050 1051

  Command-line tools:

1052
  * BACKWARD INCOMPATIBLE CHANGE: All tools that output automata now
1053
    use the HOA format by default instead of the GraphViz output.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1054
    This makes it easier to pipe several commands together.
1055 1056 1057 1058 1059 1060

    If you have an old script that relies on GraphViz being the default
    output and that you do not want to update it, use
       export SPOT_DEFAULT_FORMAT=dot
    to get the old behavior back.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1061 1062 1063
  * Tools that output automata now accept -d as a shorthand for --dot
    since requesting the GraphViz (a.k.a. dot) output by hand is now
    more frequent.
1064 1065
    randaut's short option for specifying edge-density used to be -d:
    it has been renamed to -e.
1066

1067
  * The SPOT_DEFAULT_FORMAT environment variable can be set to 'dot'
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1068 1069
    or 'hoa' to force a default output format for automata.  Additional
    options may also be added, as in SPOT_DEFAULT_FORMAT='hoa=iv'.
1070

1071 1072
  * autfilt has a new option: --is-inherently-weak.

Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1073 1074 1075
  * The --check=strength option of all tools that produce automata
    will also test if an automaton is inherently weak.

1076 1077
  Library:

1078 1079 1080 1081 1082 1083 1084 1085 1086
  * Installed headers now assume that they will be included as
    #include <spot/subdir/header.hh>
    instead of
    #include <subdir/header.hh>

    This implies that when Spot headers are installed in
    /usr/include/spot/... (the default when using the Debian packages)
    or /usr/local/include/spot/... (the default when compiling from
    source), then it is no longuer necessary to add
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
1087 1088 1089
    -I/usr/include/spot or -I/usr/local/include/spot when compiling,
    as /usr/include and /usr/local/include are usually searched by
    default.