anchor.diff:  //    LineContinuation
   fragment
   DoubleStringCharacter
  -: ~["\\\n\r\u2028\u2029]
  -| '\\' EscapeSequence
  -| LineContinuation
  +: (~["\\\n\r\u2028\u2029]|'\\' EscapeSequence|LineContinuation)
   ;
   
   // SingleStringCharacter::
  
positive.code: //    " DoubleStringCharacters[opt] "
  //    ' SingleStringCharacters[opt] '
  StringLiteral
  : '"' DoubleStringCharacters? '"'
  | '\'' SingleStringCharacters? '\''
  ;
  
  // DoubleStringCharacters::
  
negative.code: //    UnicodeEscapeSequence
  fragment
  EscapeSequence
  : (CharacterEscapeSequence|'0'|HexEscapeSequence|UnicodeEscapeSequence)
  ;
  
  // CharacterEscapeSequence::
  