def check(formula):
"""Parse formula string and create abstract syntax tree (AST).
"""
ast = lexyacc.parse(formula)
dfa = trs.automata.FiniteWordAutomaton(atomic_proposition_based=False,
deterministic=True)
dfa.alphabet |= {'!', 'W', 'U', 'G', 'F',
'U_left', 'U_right',
'W_left', 'W_right'}
dfa.states.add_from({'gf', 'fg', 'g', 'f'})
dfa.states.initial.add('gf')
dfa.transitions.add('gf', 'fg', letter='!')
dfa.transitions.add('fg', 'gf', letter='!')
dfa.transitions.add('g', 'f', letter='!')
dfa.transitions.add('f', 'g', letter='!')
dfa.transitions.add('gf', 'gf', letter='W')
dfa.transitions.add('gf', 'gf', letter='U_left')
dfa.transitions.add('gf', 'gf', letter='G')
dfa.transitions.add('fg', 'fg', letter='U')
dfa.transitions.add('fg', 'fg', letter='F')
dfa.transitions.add('fg', 'fg', letter='W_right')
dfa.transitions.add('gf', 'f', letter='U_right')
dfa.transitions.add('gf', 'f', letter='F')
dfa.transitions.add('fg', 'g', letter='W_left')
dfa.transitions.add('fg', 'g', letter='G')
dfa.transitions.add('g', 'g', letter='W')
dfa.transitions.add('g', 'g', letter='G')
dfa.transitions.add('f', 'f', letter='U')
dfa.transitions.add('f', 'f', letter='F')
# plot tree automaton
# dfa.save('dfa.pdf')
# plot parse tree
sast.dump_dot(ast, 'ast.dot')
# sync product of AST with DFA,
# to check acceptance
Q = [(ast, 'gf')]
while Q:
s, q = Q.pop()
logger.info('visiting: ' + str(s) + ', ' + str(q))
if isinstance(s, sast.Unary):
op = s.operator
if op in {'!', 'G', 'F'}:
t = dfa.transitions.find(q, letter=op)
if not t:
raise Exception('not in fragment')
qi, qj, w = t[0]
Q.append((s.operand, qj))
else:
# ignore
Q.append((s.operand, q))
elif isinstance(s, sast.Binary):
op = s.operator
if op in {'W', 'U'}:
t = dfa.transitions.find(q, letter=op)
if t:
qi, qj, w = t[0]
Q.append((s.op_l, qj))
Q.append((s.op_r, qj))
else:
t = dfa.transitions.find(q, letter=op + '_left')
if not t:
raise Exception('not in fragment')
qi, qj, w = t[0]
Q.append((s.op_l, qj))
t = dfa.transitions.find(q, letter=op + '_right')
if not t:
raise Exception('not in fragment')
qi, qj, w = t[0]
Q.append((s.op_r, qj))
else:
# ignore
Q.append((s.op_l, q))
Q.append((s.op_r, q))
elif isinstance(s, sast.Var):
print('reached var')
return ast
def check(formula):
"""Parse formula string and create abstract syntax tree (AST).
"""
ast = lexyacc.parse(formula)
dfa = trs.automata.FiniteWordAutomaton(atomic_proposition_based=False,
deterministic=True)
dfa.alphabet |= {
'!', 'W', 'U', 'G', 'F', 'U_left', 'U_right', 'W_left', 'W_right'
}
dfa.states.add_from({'gf', 'fg', 'g', 'f'})
dfa.states.initial.add('gf')
dfa.transitions.add('gf', 'fg', letter='!')
dfa.transitions.add('fg', 'gf', letter='!')
dfa.transitions.add('g', 'f', letter='!')
dfa.transitions.add('f', 'g', letter='!')
dfa.transitions.add('gf', 'gf', letter='W')
dfa.transitions.add('gf', 'gf', letter='U_left')
dfa.transitions.add('gf', 'gf', letter='G')
dfa.transitions.add('fg', 'fg', letter='U')
dfa.transitions.add('fg', 'fg', letter='F')
dfa.transitions.add('fg', 'fg', letter='W_right')
dfa.transitions.add('gf', 'f', letter='U_right')
dfa.transitions.add('gf', 'f', letter='F')
dfa.transitions.add('fg', 'g', letter='W_left')
dfa.transitions.add('fg', 'g', letter='G')
dfa.transitions.add('g', 'g', letter='W')
dfa.transitions.add('g', 'g', letter='G')
dfa.transitions.add('f', 'f', letter='U')
dfa.transitions.add('f', 'f', letter='F')
# plot tree automaton
# dfa.save('dfa.pdf')
# plot parse tree
sast.dump_dot(ast, 'ast.dot')
# sync product of AST with DFA,
# to check acceptance
Q = [(ast, 'gf')]
while Q:
s, q = Q.pop()
logger.info('visiting: ' + str(s) + ', ' + str(q))
if isinstance(s, sast.Unary):
op = s.operator
if op in {'!', 'G', 'F'}:
t = dfa.transitions.find(q, letter=op)
if not t:
raise Exception('not in fragment')
qi, qj, w = t[0]
Q.append((s.operand, qj))
else:
# ignore
Q.append((s.operand, q))
elif isinstance(s, sast.Binary):
op = s.operator
if op in {'W', 'U'}:
t = dfa.transitions.find(q, letter=op)
if t:
qi, qj, w = t[0]
Q.append((s.op_l, qj))
Q.append((s.op_r, qj))
else:
t = dfa.transitions.find(q, letter=op + '_left')
if not t:
raise Exception('not in fragment')
qi, qj, w = t[0]
Q.append((s.op_l, qj))
t = dfa.transitions.find(q, letter=op + '_right')
if not t:
raise Exception('not in fragment')
qi, qj, w = t[0]
Q.append((s.op_r, qj))
else:
# ignore
Q.append((s.op_l, q))
Q.append((s.op_r, q))
elif isinstance(s, sast.Var):
print('reached var')
return ast