anchor.diff:  
   fragment
   StringPart
  -    : ( ~ /* NonStringChars*/ ('{' | '\\' | '"' | '$' | '\'')
  +    : ( ~ /* NonStringChars*/ ('\\' | '"' | '\'')
       | EscapeSequence) *
       ;
       
  
positive.code: 
  fragment
  NonStringChars
      :    '{' | '\\' | '"' | '$' | '\''
      ;
  
  fragment
  
negative.code:         |   's' 
          |   '\"' 
          |   '\''
          )          
      ;
  
  