Re: The old "Object.Method" syntax debate

["David C. Hoos" <david.c.hoos.sr@ada95.com>]

"Preben Randhol" <randhol+abuse@pvv.org> wrote in message
news:slrnbcnoqe.bde.randhol+abuse@kiuk0152.chembio.ntnu.no...
> David C. Hoos wrote:
> >
> > The parameter is required to identify the "class" of which Prim is an
> > operation (method in classical OO-speak).  In Ada, you can have
> > multiple "classes" (hopefully related) within a single package, and
there
> > is no class structure to encapsulate both fields and methods of the
class.
> >
> > When the fields and methods are encapsulated in a class structure, then
> > you have an implicit controlling parameter (e.g., named "this").  In Ada
> > it needs to be explicit.
> >
> > In this example, X is the object whose state is changed by the
operation.
>
> Yes, but only because it is the first parameter of the procedure, right?
No, it's because T is the type of which Prim is a primitive operation.

See RM95 N (28) which says:

Primitive operations.  The primitive operations of a type are the operations
(such as subprograms) declared together with the type declaration. They are
inherited by other types in the same class of types. For a tagged type, the
primitive subprograms are dispatching subprograms, providing run-time
polymorphism. A dispatching subprogram may be called with statically tagged
operands, in which case the subprogram body invoked is determined at compile
time. Alternatively, a dispatching subprogram may be called using a
dispatching
call, in which case the subprogram body invoked is determined at run time.

>
>    "In Ada you model the problem space, not the solution space."
>                                              -- Robert I. Eachus
>
> Preben
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