Re: default formal parameters in generic declarations

[Eric Hughes <eric.eh9@gmail.com>]

On Mar 7, 3:51 am, Georg Bauhaus <rm.tsoh.plus-
bug.bauh...@maps.futureapps.de> wrote:
[another example elided]
> This object
> can be overridden, passed downwards to other instantiations,
> "intercepted" by different Functionality_Interface'Class objects...
> But, as Eric has explained, going along this path does not
> yet lead to complete solution.

I would like to expand upon this.  The essential deficit is that
subprogram instantiation only addresses the middle of the life cycle
of an object, but neither it's beginning nor end.  During the middle
of the life cycle, there must be a way of hooking into the operation
of an object.  In AOP parlance, these are called cut points and their
manifestation is a subprogram (either by call or in-line).  Yet this
does not address memory allocation of the state of an aspect, which
must, in general, be allocated one-to-one (aspect-to-object).  The
easiest pattern for this simply inserts the aspect state into the
object; this is efficient and avoids explicit deallocation.  There are
other ways one might conceive of doing this, and all of them require
action at the beginning and end of the life cycle.  You could
accomplish this, say, with a controlled base type and an associative
array for arbitrary dereference.  Without type or package formal
parameters, however, it's impossible to get the aspect state simply
inserted.

Eric