def __create_key_fsa(self, dict):
"""
Create an FSA from the keys in a map.
"""
def add_key(fsa, key):
def add_new_transition(fsa, start, label, end, tag):
for x in fsa.transitions_from(start):
if x == (label, end, tag):
return False
fsa.add_transition(start, label, end, tag)
for j in range(len(key), -1, -1):
if j > 0 and fsa.has_state(key[:j]):
break
s = key + self._separator
for i in range(j, len(s)):
c = s[i]
if i == len(s) - 1: #last step
end = fsa.get_initial()
tag = key
else:
end = s[:i + 1]
tag = None
add_new_transition(fsa, s[:i], c, end, tag)
fsa = FSA()
fsa.add_state("")
fsa.set_initial("")
fsa.set_final("")
for k, v in dict.items():
if not isinstance(v, list):
raise TypeError(v)
add_key(fsa, k)
return fsa
def compile(self, force = False):
"""
Compile the set of rules into a Deterministic State Automaton (DFSA).
If the grammar has never been compiled or it has been modified after last compilation, it will be translated into an FSA.
The result will be kept available until the rules are modified or the grammar reset.
The algorithm calls recursively the L{bnf.NormalExpression.insert_transitions} method.
If the C{force} flag is off and the grammar was already compiled and was not updated, the old result is taken with no recompiling.
@see: L{Finite State Automaton<fsa.FSA>}
@param force: Recompile grammar even if it has already been validated and compiled.
@type force: bool
@raise GrammarError: If anomalies are encountered while precompiling.
@return: A parser for the grammar.
@rtype: fsa.Parser
"""
if force or not self.__valid and self.__compiled is None:
self.__valid = False
self.browse()
nfa = FSA()
initial = nfa.add_state()
nfa.set_initial(initial)
final = nfa.add_state()
nfa.set_final(final)
s = self.__rules[self.start]
s.insert_transitions(self, nfa, initial, final, ())
#rewriting to save memory
nfa = nfa.reduced()
nfa = nfa.minimized()
self.__compiled = _GrammarParser(nfa)
self.__valid = True
return self.__compiled
