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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) + "'" | |