This should will come handy to implement the convertion from LTL to
alternating automata, and to handle automata with multiple initial
states.
* spot/twaalgos/alternation.hh, spot/twaalgos/alternation.cc: New files.
* spot/twaalgos/Makefile.am: Add them.
* python/spot/impl.i: Add bindings.
* tests/python/alternating.py: Test states_and.
The only missing point is that the HOA parser cannot deal with multiple
universal initial states, as seen in parseaut.test.
* spot/graph/graph.hh (new_univ_dests): New function, extracted from...
(new_univ_edge): ... this one.
* spot/twa/twagraph.hh (set_univ_init_state): Implement using
new_univ_dests.
* spot/twaalgos/dot.cc, spot/twaalgos/hoa.cc, python/spot/impl.i:
Add support for universal initial states.
* spot/parseaut/parseaut.yy: Add preliminary support for
universal initial states. Multiple universal initial states
are still not supported.
* tests/core/alternating.test, tests/core/parseaut.test,
tests/python/alternating.py: Adjust tests and exercise this new feature.
Currently this only reads universal branches. The parser (and the
automaton code) do not support universal initial states.
* spot/parseaut/parseaut.yy: Read universal branches. Deal with
the no-univ-branch/!univ-branch change in HOA 1.1.
* tests/python/alternating.py: Read the output of print_hoa.
* tests/core/parseaut.test: Adjust test output, and add more tests.
This only allows creating universal edges, and reading the associated
destinations.
* spot/twa/twagraph.hh (new_univ_edges, univ_dests, is_alternating): New
function.
* python/spot/impl.i: Add Python bindings.
* tests/python/alternating.py: New file.
* tests/Makefile.am: Add it.
