anchor.diff:     ;
   
   ifblock
  -   : 'if' condition statement+ ('else' statement)? 'endif'
  +   : 'if' condition statement + ('else' statement)? 'endif'
      ;
   
   whileblock
  -   : 'while' condition statement+
  +   : 'while' condition statement +
      ;
   
   doblock
  -   : 'do' statement+ 'while' condition
  +   : 'do' statement + 'while' condition
      ;
   
   assignblock
  
positive.code:    | GT
     | GTE
     | LT
     | LTE  
     ;
  
  expressionlist
  
negative.code:    : '<'
     ;
  
  
  GTE
     : '>='
     ;
  
  
  LTE
     : '<='
     ;
  
  
  