Re: Subverting 'Access for Sub-programs

[Robert Dewar <robert_dewar@my-deja.com>]

In article <37B18CF0.F50A802B@gandalf.atm.fh-luebeck.de>,
  "Dmitry A. Kazakov" <dmitry@gandalf.atm.fh-luebeck.de> wrote:
> I believe that the actual problem is in using pointers. In
90%, I would
> say, there is
> no need to pass a subroutine by pointer. It should be passed
by
> reference: What we
> need is something like (syntax is imaginary):


But passing subprograms as parameters is only one of many
possible uses of subprogram pointers. Indeed it is one of
the weakest uses, in that this particular use often can
be replaced by generics. The motivation for providing
pointers to subprograms during the Ada 95 design was
driven by other uses entirely, most notably by the need
for implementing call backs (and of course if you think
about it the use of procedure pointers implicit in
dynamic dispatching is also another kind of use completely
unrelated to the call by reference notion).

That being said, there is certainly nothing wrong with
providing a general capability here (as is done in Algol-68).


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