Re: What would you like in Ada202X?

[Shark8 <onewingedshark@gmail.com>]

On Friday, April 27, 2012 4:11:07 PM UTC-5, sbelm...@gmail.com wrote:
> On Friday, April 27, 2012 12:04:33 PM UTC-4, Shark8 wrote:
> > 
> > I thought stubs were an accepted software engineering/design practice...
> 
> procedure Shut_Down_Reactor (Reactor : Reactor_Type) is null;
> 
> The phrase "where the default behavior is null" is a contridiction in terms; calling a subprogram to achieve the effect of not calling a subprogram is simply bananas.

This is plainly false. Consider a cleanup/freeing procedure in a component-based RAD style program* when it is applied to a form having both components and [sub-]forms which contain both components and forms themselves. 

Having the base COMPONENT with a null procedure for its free is absolutely reasonable, especially if the inherited classes need not do anything special to ensure they are properly disposed of. The form and all of its component-containing children, however, must do something else: pass the free command to those children.


* I'm assuming a class hierarchy with a base COMPONENT type and two branches: the first a CONTAINER class which can hold other components (like visual controls); and one, say ITEM, which is for components which cannot have components added (like a timer). {Yes, this could be done differently, perhaps with an abstract base-class, but then you have the problem that there is no default at all and each actual object of COMPONENT would have to declare its own personal free-procedure....}