anchor.diff:  ;
   // R705
   addOperand : 
  -  (   addOperand multOp   )?   multOperand
  +  multOperand (   multOp  addOperand  )?
   ;
   // R704
   multOperand : 
  
positive.code: ;
  // R912
  printStmt : 
  PRINT format   (    COMMA   outputItemList   )?  
  Newline
  ;
  // R607
  
negative.code: ;
  // R722
  expr : 
    level5Expr ( definedBinaryOp   expr )?
  ;
  // R721
  equivOp : 
  