Fixes#468.
* python/spot/__init__.py: Add wrapper around twa::acc() and
twa::get_acceptance() to store the automaton into the acceptance
proxy, therefore ensuring that the automaton survives that proxy.
* tests/python/setacc.py: Test it.
This fixes#469.
* spot/misc/bitset.hh (bitset::operator-): Rewrite.
I cannot follow the logic of the old implementation.
* tests/python/setacc.py: Add a test case, inspired from #469.
* spot/twa/acc.cc: Recoginize the single-pair case.
* python/spot/impl.i: Return the vector instead of taking it
by reference.
* tests/python/setacc.py: Add test cases.
* NEWS: Mention those changes.
* spot/twa/acc.hh: Hide default constructors, so that we can have
keyword arguments on the main constructor.
* python/spot/impl.i: Add __repr__.
* tests/python/setacc.py: Test it.
Hopefully fixes#359.
* spot/misc/trival.hh: Declare a global operator==(trival,trival) that
replace the specialized operator==(bool,trival), and the in class
trival::operator(trival), thanks to the implicit construction from
bool to trival. Make the repr_t/value_t constructor explicit, are
those are mostly internal to the library and may cause conflicts.
* spot/twa/twa.hh: Adjust to construct trival explicitly.
* python/spot/impl.i: Since Swig/Python does not support global
comparison operators, implement a member version, supporting
only __eq__(trival,bool) as before.
* tests/python/setacc.py: Adjust erroneous code.
* tests/python/trival.py: Add test cases.
Reported by Juraj Major.
* spot/twa/twa.hh: check num_sets() in prop_state_acc() so we do not
have to set it in set_acceptance(), causing trouble if set_acceptance()
is called multiple times.
* tests/python/setacc.py: New test case.
* tests/Makefile.am: Add it.
* THANKS: Add Juraj.
* NEWS: Mention the bug.
