Re: Visibility and access to "public" attributes

["Gavin Collings" <gcollings@sperry-sun.com>]

Don Harrison <nospam@thanks.com.au> wrote in article
<EFv4p4.ME2@syd.csa.com.au>...
> I wrote:
> 
> :Mike Card wrote:
> 
> :I accept this more accurately emulates the Eiffel functionality, and.. 
> :
> ::.. there is no restriction in Ada that prevents an access function
> ::from having the same name as a class' (tagged type's) attribute.
> :
> :True.
> 
> What remains, of course, is the fact that the Eiffel mechanism is simpler 
> and more direct - objectively-speaking, that is.  :)
> 
> Why objectively? Because in Eiffel, the attribute is made available in one
> step and in Ada, two steps. Less steps implies directness which, in turn, 
> implies simplicity, so we can conclude that the Eiffel mechanism is both 
> more direct and simpler.

... than Ada ... Agreed.  Would you care to contrast the Eiffel mechanism
(objectively, of course) with that specified for Delphi properties.  Here I
have complete freedom to define within say class circle.

   property Radius : Double read fRadius    - gives a read-only radius
or property Radius : Double read fRadius write fRadius - gives direct
read/write access
or property Radius : Double read fRadius write SetRadius - accessor called on
set

and write client code like

   circle1.radius := circle2.radius;

Apart, perhaps, from the overhead of having to declare fRadius separately,
this method looks certainly more flexible and probably in most interesting
cases more direct than the Eiffel approach.

-- 
Gavin Collings
gcollings@sperry-sun.com