anchor.diff:  
   
   STRING
  -   : '"' S_CHAR* '"'
  +   : '"' ( S_CHAR | S_ESCAPE )* '"'
      ;
   
   
  
positive.code:    ;
  
  if_equation
     : 'if' expression 'then' (equation ';')* ('elseif' expression 'then')* (equation ';')* ('else' (equation ';')*)? 'end' 'if'
     ;
  
  if_statement
     : 'if' expression 'then' (statement ';')* ('elseif' expression 'then')* (statement ';')* ('else')? (statement ';')* 'end' 'if'
     ;
  
  for_equation
  
negative.code: WS
     : [ \r\n\t] + -> channel (HIDDEN)
     ;
  
  COMMENT
      :   '/*' .*? '*/' -> channel (HIDDEN)
      ;
  
  LINE_COMMENT
      :   '//' ~[\r\n]* -> channel (HIDDEN)
      ;
  