Update the definition of DFA and part of the function of NFA to DFA t…

…ransformation

dfa/construction.py

@@ -0,0 +1,45 @@
+from parse.parse import (
+    closure,
+    move,
+)
+from dfa.dfa import (
+    Dfa,
+    MAX_DFA_STATUS_NUM,
+)
+from nfa.nfa import ASCII_COUNT
+from utils import list_dict
+
+
+def convert_to_dfa(nfa_start_node):
+    jump_table = list_dict(MAX_DFA_STATUS_NUM)
+    dfa_list = []
+    n_closure = closure(nfa_start_node)
+    dfa = Dfa.nfas_to_dfa(n_closure)
+    dfa_list.append(dfa)
+
+    dfa_index = 0
+    while dfa_index < len(dfa_list):
+        dfa = dfa_list[dfa_index]
+        for i in range(ASCII_COUNT):
+            c = chr(i)
+            nfa_move = move(dfa.nfa_sets, c)
+            if nfa_move is not None:
+                nfa_closure = closure(nfa_move)
+                new_dfa = convert_completed(dfa_list, nfa_closure)
+                if new_dfa is None:
+                    new_dfa = Dfa.nfas_to_dfa(nfa_closure)
+                    dfa_list.append(new_dfa)
+                next_state = new_dfa.status_num
+            jump_table[dfa.status_num][c] = next_state
+        dfa_index = dfa_index + 1
+
+    return jump_table
+
+
+
+def convert_completed(dfa_list, closure):
+    for dfa in dfa_list:
+        if dfa.nfa_sets == closure:
+            return dfa
+
+    return None

dfa/dfa.py

@@ -0,0 +1,22 @@
+MAX_DFA_STATUS_NUM = 256
+
+
+class Dfa(object):
+    STATUS_NUM = 0
+
+    def __init__(self):
+        self.nfa_sets = set()
+        self.accepted = False
+        self.status_num = -1
+
+    @classmethod
+    def nfas_to_dfa(cls, nfas):
+        dfa = cls()
+        for n in nfas:
+            dfa.nfa_sets.append(n)
+            if n.next_1 is None and n.next_2 is None:
+                dfa.accepted = True
+
+        dfa.status_num = Dfa.STATUS_NUM
+        Dfa.STATUS_NUM = Dfa.STATUS_NUM + 1
+        return dfa

nfa/construction.py

@@ -97,7 +97,6 @@ def nfa_set_nega_char(pair_out):
         char_set_inversion(start.input_set)
 
     lexer.advance()
-
     return True
 
 

utils.py

@@ -6,3 +6,7 @@ def log(*args, **kwargs):
     value = time.localtime(int(time.time()))
     dt = time.strftime(format, value)
     print(dt, *args, **kwargs)
+
+
+def list_dict(width):
+    return [dict() for i in range(width)]