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