@:

 Synopsis

         Invoke method in same class without using a message send

 Syntax

         @:<method name>[ ( [<parameter list>] ) ]

 Arguments

         <method name> is the name of the method to be invoked. It must
         be a method in the same class as the currently executing method,
         and should either be defined in the same program module or
         according to the rules governing external methods.

         <parameter list> is the list of parameters to be sent to the
         method being invoked.

 Description

         Similar to the double-colon (::) for message sends to self,
         the 'at-colon' allows direct invocation of methods in the same
         class as the invoking method. Since the location of the invoked
         method is known in such a case, a message lookup is not necessary.
         A direct invocation of this kind is faster than the equivalent
         message send, but this is a trade-off for loss of flexibility.

 Warning

         This feature should be used with great caution, since it prevents
         methods invoked in this fashion from being overridden in a
         subclass. This is sometimes desirable, however.

         For those familiar with C++, @: allows methods to be invoked
         in a way similar to that in which ordinary (non-virtual) C++
         member functions are invoked. Because of dynamic or late binding,
         methods in Clipper normally behave in a similar way to C++ virtual
         methods.