Jison分析器生成器，移位减少了语法冲突，如何解决？

Question

我目前正在使用jison开发Visual Basic转换器。我的语法中有这些冲突：

Conflict in grammar: multiple actions possible when lookahead token is ELSE in state 11
- reduce by rule: If -> IfBlock
- shift token (then go to state 16)
Conflict in grammar: multiple actions possible when lookahead token is ELSE_IF in state 11
- reduce by rule: If -> IfBlock
- shift token (then go to state 17)
Conflict in grammar: multiple actions possible when lookahead token is TERMINATOR in state 27
- reduce by rule: IfBlock -> IF Expression THEN Body
- shift token (then go to state 13)
Conflict in grammar: multiple actions possible when lookahead token is TERMINATOR in state 29
- reduce by rule: IfBlock -> IfBlock ELSE_IF Expression THEN Body
- shift token (then go to state 13)

States with conflicts:
State 11
  If -> IfBlock . #lookaheads= $end TERMINATOR IF_END ELSE ELSE_IF SUB_END
  If -> IfBlock .ELSE Body IF_END #lookaheads= $end TERMINATOR IF_END ELSE ELSE_IF SUB_END
  IfBlock -> IfBlock .ELSE_IF Expression THEN Body #lookaheads= $end ELSE ELSE_IF TERMINATOR SUB_END IF_END
State 27
  IfBlock -> IF Expression THEN Body . #lookaheads= $end ELSE ELSE_IF TERMINATOR SUB_END IF_END
  Body -> Body .TERMINATOR Line
  Body -> Body .TERMINATOR
State 29
  IfBlock -> IfBlock ELSE_IF Expression THEN Body . #lookaheads= $end ELSE ELSE_IF TERMINATOR SUB_END IF_END
  Body -> Body .TERMINATOR Line
  Body -> Body .TERMINATOR

这里是我的语法的简化版本（删除了动作：]：>

const grammar = {
  Root: [
    [
      ''
    ],
    [
      'Body'
    ]
  ],
  Body: [
    [
      'Line'
    ],
    [
      'Body TERMINATOR Line'
    ],
    [ 'Body TERMINATOR' ]
  ],
  Line: [ [ 'Expression' ], [ 'Statement' ] ],
  Statement: [ [ 'Return' ], [ 'If' ] ],
  Expression: [ [ 'Code' ] ],
  Return: [
    [
      'RETURN Expression'
    ],
    [
      'RETURN'
    ]
  ],
  Code: [
    [
      'SUB_START Identifier PARAM_START ParamList PARAM_END TERMINATOR Body SUB_END'
    ]
  ],
  IfBlock: [
    [
      'IF Expression THEN Body'
    ],
    [
      'IfBlock ELSE_IF Expression THEN Body'
    ]
  ],
  If: [
    [ 'IfBlock' ],
    [
      'IfBlock ELSE Body IF_END'
    ]
  ]
}
当我尝试为If语句实现规则时，就会发生冲突，它似乎与Body规则冲突。我花了将近一天的时间来解决它，但是我不能。我知道解析器只能向前看一个令牌，但是我自己找不到解决方案。而且我必须与吉森结盟，所以我不能使用其他解析器生成器。我的语法有什么解决方法吗？

我目前正在使用jison开发Visual Basic转换器。而且我的语法中有这些冲突：语法中的冲突：当状态为11的超前标记为ELSE时，可能会执行多个动作-...

Answer 1

看这些作品：