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