def thompson(exp):
"""Fonction de transformation d'une expression postfixé en automate
Algorithme prenant une expression régulière, et retournant l'automate de Thompson calculant le langage correspondant à cette expression.
"""
out_stack = prefix_regex(exp)
print(out_stack)
graph_stack = []
thompson_graph = Graph()
operators = ['*', '.', '+']
states = []
for c in out_stack:
# Si c'est un caractère
# Créer un graphe avec un etat initial et etat final, et transition en lisant c
if c not in operators:
print("1-", c)
g = Graph()
print(len(graph_stack))
g.alphabet.append(c) # ajouter la lettre à l'alphabet
i = gen_state(states) # générer l'état initial
states.append(i)
g.initialState = i
g.states.append(i)
j = gen_state(states) # générer l'état final
states.append(j)
g.finalStates.append(j)
g.states.append(j)
# ajouter la transition (initial, c, final)
g.transitions.append(Transition(i, c, j))
# ajouter le graphe à la pile
graph_stack.append(g)
# Si
elif c == '*':
print("2-", c)
g = Graph()
g = graph_stack.pop() # récupérer le dernier graphe dans la pile
print(len(graph_stack))
g.transitions.append(
Transition(g.finalStates[0], '\u03b5', g.initialState))
i = gen_state(states) # générer l'état initial
g.states.append(i)
states.append(i)
g.transitions.append(Transition(i, '\u03b5', g.initialState))
g.initialState = i
j = gen_state(states) # générer l'état final
g.states.append(j)
states.append(j)
g.transitions.append(Transition(g.finalStates[0], '\u03b5', j))
g.finalStates = []
g.finalStates.append(j)
g.transitions.append(
Transition(g.initialState, '\u03b5', g.finalStates[0]))
graph_stack.append(g)
# Si
elif c == '+':
print("3-", c)
print(len(graph_stack))
g1 = graph_stack.pop()
g2 = graph_stack.pop()
g = Graph()
g.states = list(set().union(g1.states, g2.states))
# g.states = [state for state in g1.states if state not in g.states]
# g.states = [state for state in g2.states if state not in g.states]
g.alphabet = list(set().union(g1.alphabet, g2.alphabet))
# g.alphabet = [c for c in g1.alphabet if c not in g.alphabet]
# g.alphabet = [c for c in g2.alphabet if c not in g.alphabet]
for node in g1.transitions:
g.transitions.append(node)
for node in g2.transitions:
g.transitions.append(node)
i = gen_state(states) # générer l'état initial
g.states.append(i)
states.append(i)
g.transitions.append(Transition(i, '\u03b5', g1.initialState))
g.transitions.append(Transition(i, '\u03b5', g2.initialState))
g.initialState = i
j = gen_state(states) # générer l'état final
g.states.append(j)
states.append(j)
g.transitions.append(Transition(g1.finalStates[0], '\u03b5', j))
g.transitions.append(Transition(g2.finalStates[0], '\u03b5', j))
g.finalStates = []
g.finalStates.append(j)
graph_stack.append(g)
# si
elif c == '.':
print("4-", c)
print(len(graph_stack))
g1 = graph_stack.pop()
g2 = graph_stack.pop()
g = Graph()
g.transitions = [node for node in g2.transitions]
g.alphabet = list(set().union(g1.alphabet, g2.alphabet))
g.states = [
state for state in g1.states
if state not in g.states and state != g1.initialState
]
g.states = list(set().union(g.states, g2.states))
g.initialState = g2.initialState
g.finalStates.append(g1.finalStates[0])
for node in g1.transitions:
if node.mFrom != g1.initialState:
g.transitions.append(node)
else:
g.transitions.append(
Transition(g2.finalStates[0], node.mValue, node.mGoto))
graph_stack.append(g)
thompson_graph = graph_stack.pop()
return thompson_graph
def minimisation(graph):
"""Fonction de minimisation d'un automate.
Algorithme calculant un automate déterministe minimal équivalent au premier.
"""
print("min")
final_states = graph.getFinalStates()
states = graph.getStates()
alphabet = graph.getAlphabet()
partitions = [[], []]
# Créer la partition initiale P0 = { {état finaux}, {états non finaux} }
for state in states:
if state in final_states:
partitions[0].append(state)
else:
partitions[1].append(state)
print(partitions)
i = 0
while (i < len(partitions)):
# Récupérer les pairs des éléments de la partition
pairs = list(combinations(partitions[i], 2))
distinguishable = False
for p in pairs:
if distinguishable:
break
for letter in alphabet:
# Récupérer les transitions possibles depuis la paire d'états avec la lettre
t1 = graph.getStateTransitionsLetter(p[0], letter)
t2 = graph.getStateTransitionsLetter(p[1], letter)
if (len(t1) == 0 or len(t2) == 0):
distinguishable = False
elif (len(t1) != 0 and len(t2) == 0):
x = -1
for j in range(len(partitions)):
if (t1[0].mGoto in partitions[j]):
x = j
distinguishable = True
partitions[i].remove(p[0])
partitions.append(list(p[0]))
elif (len(t1) == 0 and len(t2) != 0):
x = -1
for j in range(len(partitions)):
if (t2[0].mGoto in partitions[j]):
x = j
distinguishable = True
partitions[i].remove(p[1])
partitions.append(list(p[1]))
else:
x = -1
y = -1
for j in range(len(partitions)):
if (t1[0].mGoto in partitions[j]):
x = j
if (t2[0].mGoto in partitions[j]):
y = j
# Si les états d'arrivée des 2 noeuds sont dans 2 partitions différentes
# Alors séparer les états dans la liste des partitions*
if x != -1 and y != -1 and x != y:
distinguishable = True
print(partitions, ' || ', p[1], ' || ', i)
partitions[i].remove(p[1])
partitions.append(list(p[1]))
# Révenir au début de la liste des partitions car changement
i = 0
break
else:
distinguishable = False
i = i + 1
print(partitions)
# Construire le graphe minimal
graph_min = Graph()
graph_min.alphabet = alphabet
for p in range(len(partitions)):
graph_min.states.append(str(p+1))
for fs in graph.finalStates:
if fs in partitions[p]:
graph_min.finalStates.append(str(p+1))
break
for state in graph.states:
for i in range(len(partitions)):
# Groupe de l'état source
if state in partitions[i]:
x = i
break
trans = graph.getStateTransitions(state)
for tr in trans:
# Groupe de l'état destination
for j in range(len(partitions)):
if tr.mGoto in partitions[j]:
y = j
break
# Nouvelle transition entre deux groupes dans l'automate minimal
new = Transition(str(x + 1), tr.mValue, str(y + 1))
if new not in graph_min.transitions:
graph_min.transitions.append(new)
for i in range(len(partitions)):
if graph.initialState in partitions[i]:
k = i
break
graph_min.initialState = str(k + 1)
return graph_min
