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#
# Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
# Use of this file is governed by the BSD 3-clause license that
# can be found in the LICENSE.txt file in the project root.
#/
# A DFA walker that knows how to dump them to serialized strings.#/
from io import StringIO
from antlr4 import DFA
from antlr4.Utils import str_list
from antlr4.dfa.DFAState import DFAState
class DFASerializer(object):
__slots__ = ('dfa', 'literalNames', 'symbolicNames')
def __init__(self, dfa:DFA, literalNames:list=None, symbolicNames:list=None):
self.dfa = dfa
self.literalNames = literalNames
self.symbolicNames = symbolicNames
def __str__(self):
if self.dfa.s0 is None:
return None
with StringIO() as buf:
for s in self.dfa.sortedStates():
n = 0
if s.edges is not None:
n = len(s.edges)
for i in range(0, n):
t = s.edges[i]
if t is not None and t.stateNumber != 0x7FFFFFFF:
buf.write(self.getStateString(s))
label = self.getEdgeLabel(i)
buf.write("-")
buf.write(label)
buf.write("->")
buf.write(self.getStateString(t))
buf.write('\n')
output = buf.getvalue()
if len(output)==0:
return None
else:
return output
def getEdgeLabel(self, i:int):
if i==0:
return "EOF"
if self.literalNames is not None and i<=len(self.literalNames):
return self.literalNames[i-1]
elif self.symbolicNames is not None and i<=len(self.symbolicNames):
return self.symbolicNames[i-1]
else:
return str(i-1)
def getStateString(self, s:DFAState):
n = s.stateNumber
baseStateStr = ( ":" if s.isAcceptState else "") + "s" + str(n) + ( "^" if s.requiresFullContext else "")
if s.isAcceptState:
if s.predicates is not None:
return baseStateStr + "=>" + str_list(s.predicates)
else:
return baseStateStr + "=>" + str(s.prediction)
else:
return baseStateStr
class LexerDFASerializer(DFASerializer):
def __init__(self, dfa:DFA):
super().__init__(dfa, None)
def getEdgeLabel(self, i:int):
return "'" + chr(i) + "'"
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