anchor.diff:          { fa.addParameterList($p2.parameterList); }
         )*
         COMPUTE?
  -      e1=expression
  +      e1=functionOrExpression
         { fa.setExpression($e1.expression); 
           $expression = new Expression(null); 
           $expression.setTerm(fa); }
  
positive.code:     | selfReference
      | nonstringLiteral
      | prefixOperatorStart
      ;
  
  prefixOperatorStart
  
negative.code: //that distinguish declarations from
  //expressions
  declarationStart
      : VALUE_MODIFIER
      | FUNCTION_MODIFIER LIDENTIFIER //to disambiguate anon functions
      | ASSIGN
      | VOID_MODIFIER
      | INTERFACE_DEFINITION
      | CLASS_DEFINITION
      | OBJECT_DEFINITION
      | ALIAS 
      | type ELLIPSIS? LIDENTIFIER
      ;
  
  statement returns [Statement statement]
  