Re: preventing inheritance

[Tom Moran <tmoran@bix.com>]

> --still strikes me as a perfectly natural way to model this problem
> domain.  Why do you think this looks "bizarre"?
  It looks eminently reasonable from a design perspective, and indeed,
I'll probably change the existing code to that approach.  But I think it
looks 'bizarre' from the perspective of a user because:
1) Of the two dozen operations on Edit_Control, this is the _only_ one
that doesn't also work on Multiline_Edit_Control.  It seems that a
significant structural change is required by something small and obscure
enough to almost call a bug.  Indeed, an informal application view of
the objects Multiline_Edit_Control and Edit_Control would say the one
"is a" the other - with a glitch.  I'm tempted to simply have a 
  procedure Get_First_Character
          (Control : in out Multi_Line_Edit_Control_Type; ...
that raises "Not_Yet_Implemented"- except that defers error detection to
run time.
2) If MS in the future adds a way to implement Get_First_Character on
Multiline edit controls, it would become reasonable to move that routine
from Edit_Controls.Single_Line to Edit_Controls, leaving
Edit_Controls.Single_Line a bodyless package containing nothing but a
single type definition.  It would become yet another instance of "this
seemingly pointless complexity is here for historical reasons". 
  My difficulty is really an aesthetic one so perhaps the only solution
is to modify my aesthetic sensibilities. ;)