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Creating an automaton by adding states and transitions

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This example demonstrates how to create an automaton and then print it.

C++

#include <iostream>
#include <spot/twaalgos/hoa.hh>
#include <spot/twa/twagraph.hh>

int main(void)
{
  // The bdd_dict is used to maintain the correspondence between the
  // atomic propositions and the BDD variables that label the edges of
  // the automaton.
  spot::bdd_dict_ptr dict = spot::make_bdd_dict();
  // This creates an empty automaton that we have yet to fill.
  spot::twa_graph_ptr aut = make_twa_graph(dict);

  // Since a BDD is associated to every atomic proposition, the
  // register_ap() function returns a BDD variable number
  // that can be converted into a BDD using bdd_ithvar().
  bdd p1 = bdd_ithvar(aut->register_ap("p1"));
  bdd p2 = bdd_ithvar(aut->register_ap("p2"));

  // Set the acceptance condition of the automaton to Inf(0)&Inf(1)
  aut->set_generalized_buchi(2);

  // States are numbered from 0.
  aut->new_states(3);
  // The default initial state is 0, but it is always better to
  // specify it explicitely.
  aut->set_init_state(0U);

  // new_edge() takes 3 mandatory parameters: source state,
  // destination state, and label.  A last optional parameter can be
  // used to specify membership to acceptance sets.
  aut->new_edge(0, 1, p1);
  aut->new_edge(1, 1, p1 & p2, {0});
  aut->new_edge(1, 2, p2, {1});
  aut->new_edge(2, 1, p1 | p2, {0, 1});

  // Print the resulting automaton.
  print_hoa(std::cout, aut);
  return 0;
}
HOA: v1
States: 3
Start: 0
AP: 2 "p1" "p2"
acc-name: generalized-Buchi 2
Acceptance: 2 Inf(0)&Inf(1)
properties: trans-labels explicit-labels trans-acc
--BODY--
State: 0
[0] 1
State: 1
[0&1] 1 {0}
[1] 2 {1}
State: 2
[0 | 1] 1 {0 1}
--END--

Python

import spot
import buddy

# The bdd_dict is used to maintain the correspondence between the
# atomic propositions and the BDD variables that label the edges of
# the automaton.
bdict = spot.make_bdd_dict();
# This creates an empty automaton that we have yet to fill.
aut = spot.make_twa_graph(bdict)

# Since a BDD is associated to every atomic proposition, the register_ap()
# function returns a BDD variable number that can be converted into a BDD using
# bdd_ithvar() from the BuDDy library.
p1 = buddy.bdd_ithvar(aut.register_ap("p1"))
p2 = buddy.bdd_ithvar(aut.register_ap("p2"))

# Set the acceptance condition of the automaton to Inf(0)&Inf(1)
aut.set_generalized_buchi(2)

# States are numbered from 0.
aut.new_states(3)
# The default initial state is 0, but it is always better to
# specify it explicitely.
aut.set_init_state(0)

# new_edge() takes 3 mandatory parameters: source state, destination state, and
# label.  A last optional parameter can be used to specify membership to
# acceptance sets.  In the Python version, the list of acceptance sets the
# transition belongs to should be specified as a list.
aut.new_edge(0, 1, p1)
aut.new_edge(1, 1, p1 & p2, [0])
aut.new_edge(1, 2, p2, [1]);
aut.new_edge(2, 1, p1 | p2, [0, 1]);

# Print the resulting automaton.
print(aut.to_str('hoa'))
HOA: v1
States: 3
Start: 0
AP: 2 "p1" "p2"
acc-name: generalized-Buchi 2
Acceptance: 2 Inf(0)&Inf(1)
properties: trans-labels explicit-labels trans-acc
--BODY--
State: 0
[0] 1
State: 1
[0&1] 1 {0}
[1] 2 {1}
State: 2
[0 | 1] 1 {0 1}
--END--