anchor.diff:          | listComprehension
           | binaryComprehension
           | tuple
  -      //  | struct
           | '(' expr ')'
           | 'begin' exprs 'end'
           | ifExpr
  
positive.code: 
  tuple : '{' exprs? '}' ;
  
  
  /* struct : tokAtom tuple ; */
  
  
negative.code: 
  expr500 : expr600 (multOp expr600)* ;
  
  expr600 : prefixOp expr600
          | expr650 ;
  
  expr650 : mapExpr
          | expr700 ;
  
  expr700 : functionCall
          | recordExpr
  