Kinds of 'subprograms'
Marcel Weiher
marcel at system.de
Mon May 17 08:50:24 UTC 1999
> From: "Michael S. Klein" <mklein at alumni.caltech.edu>
>
> [ 'method' kindLike: 'subroutine' SNIP ]
>
> I call all of these kinda things 'subprograms'.
>
> You can view macros as a weak, but easy to explain
> kind of subprogramming technology.
>
> You can view generic functions as a strong, but hard to
> explain kind.
>
> The spectrum:
>
> add-hoc
> macros
> subroutines
> functions
> methods
> generic functions
> <yet to be invented>
These are all places in a system where computation happens, software
architecture calls them 'components' a category that is broad enough
to include filters, processes and layers as well as lower level
constructs such as methods/procedures. These places are put together
to form a system by 'connectors' such as message sends, procedure
calls, data-flow pipes, signals or broadcasts.
The components method and procedure/subroutine aren't really
dissimilar, it is the connectors, procedure-call vs. message-send
that aren't really at all alike. Apart from the dynamic lookup,
connections can be made from within methods with message sends in an
organized way, and messages don't really have to trigger the
execution of methods, they could just as well simply be stored, or
matched by a rule-system or whatever.
Marcel
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