anchor.diff:  unaryTail : unaryMessage ws unaryTail? ws;
   unaryMessage : ws unarySelector ~COLON;
   unarySelector : IDENTIFIER;
  +keywords : KEYWORD+;
   reference : variable;
   binaryTail : binaryMessage binaryTail?;
   binaryMessage : ws BINARY_SELECTOR ws (unarySend | operand);
  
positive.code:   
    2013/11/27 James Ladd (object@redline.st)
  */
  
  grammar Smalltalk;
  
  
negative.code: SEPARATOR : (' ' | '\t' | '\r' | '\n' | '\u00A0' | '\uFEFF' | '\u2028' | '\u2029')+;
  STRING : '\'' (.)*? '\'';
  COMMENT : '"' (.)*? '"';
  
  