anchor.diff:          |   'n'
           |   'f'
           |   'r'
  +        |   '\\'
           |   '"'
           |   '\''
           |   '`'
  
positive.code: 
  fragment
  NonStringChars
      :    '\\' | '"' | '\''
      ;
  
  fragment
  StringPart
      : ( ~ /* NonStringChars*/ ('\\' | '"' | '\'')
      | EscapeSequence) *
      ;
      
  
negative.code:     ;
  
  QUOTEDLITERAL
      :   '\'' QuotedLiteralPart '\''
      ;
  
  fragment
  QuotedLiteralPart
      : ~('\'')
      ;
  
  SIMPLESTRINGLITERAL
  