def test_init_npda_missing_formal_params(self):
"""Should raise an error if formal NPDA parameters are missing."""
with self.assertRaises(TypeError):
NPDA(states={'q0', 'q1', 'q2'},
input_symbols={'a', 'b'},
initial_state='q0',
final_states={'q0'})
def do_npda(alphabet, stack_symb, states_dict):
npda = NPDA(states={'s0'},
input_symbols=alphabet,
stack_symbols=stack_symb,
transitions={
's0': states_dict,
},
initial_state='s0',
initial_stack_symbol=(MARKER_STACK, 'E'),
final_states={'s0'},
acceptance_mode='both')
return npda
def test_init_npda_no_acceptance_mode(self):
"""Should create a new NPDA."""
new_npda = NPDA(states={'q0'},
input_symbols={'a', 'b'},
stack_symbols={'#'},
transitions={'q0': {
'a': {
'#': {('q0', '')}
},
}},
initial_state='q0',
initial_stack_symbol='#',
final_states={'q0'})
self.assertEqual(new_npda.acceptance_mode, 'both')
def test_init_npda(self):
"""Should copy NPDA if passed into NPDA constructor."""
new_npda = NPDA.copy(self.npda)
self.assert_is_copy(new_npda, self.npda)
def setup(self):
"""Reset test automata before every test function."""
# DPDA which which matches zero or more 'a's, followed by the same
# number of 'b's (accepting by final state)
self.dpda = DPDA(states={'q0', 'q1', 'q2', 'q3'},
input_symbols={'a', 'b'},
stack_symbols={'0', '1'},
transitions={
'q0': {
'a': {
'0': ('q1', ('1', '0'))
}
},
'q1': {
'a': {
'1': ('q1', ('1', '1'))
},
'b': {
'1': ('q2', '')
}
},
'q2': {
'b': {
'1': ('q2', '')
},
'': {
'0': ('q3', ('0', ))
}
}
},
initial_state='q0',
initial_stack_symbol='0',
final_states={'q3'})
# NPDA which matches palindromes consisting of 'a's and 'b's
# (accepting by final state)
# q0 reads the first half of the word, q1 the other half, q2 accepts.
# But we have to guess when to switch.
self.npda = NPDA(states={'q0', 'q1', 'q2'},
input_symbols={'a', 'b'},
stack_symbols={'A', 'B', '#'},
transitions={
'q0': {
'': {
'#': {('q2', '#')},
},
'a': {
'#': {('q0', ('A', '#'))},
'A': {
('q0', ('A', 'A')),
('q1', ''),
},
'B': {('q0', ('A', 'B'))},
},
'b': {
'#': {('q0', ('B', '#'))},
'A': {('q0', ('B', 'A'))},
'B': {
('q0', ('B', 'B')),
('q1', ''),
},
},
},
'q1': {
'': {
'#': {('q2', '#')}
},
'a': {
'A': {('q1', '')}
},
'b': {
'B': {('q1', '')}
},
},
},
initial_state='q0',
initial_stack_symbol='#',
final_states={'q2'})