anchor.diff:        assignableExpression & assignmentOperator & expression
         | conditionalExpression & cascadeSection.star()
         | throwExpression
  -      | rethrowExpression
       ;
   
   
  
positive.code:       assignableExpression & assignmentOperator & expressionWithoutCascade
        | conditionalExpression
        | throwExpressionWithoutCascade
        | rethrowExpression
      ;
  
      expressionList =  expression.separatedBy(comma);
  
negative.code:     ;
      functionExpression = formalParameterList & functionExpressionBody;
  
      throwExpression = THROW & expression;
      throwExpressionWithoutCascade = THROW & expressionWithoutCascade;
  
  