RE: Procedure types

From: Fyodor Tkachov <"Fyodor>
Date: Sun, 28 Nov 2004 14:54:03 +0300

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Robert,

> Let me summarise the advantages of objects over procedure
> variables you have pointed out (my words, not yours):
>
> Advantage 1. "If someone unloads some of your modules while
> you are still using them the o-o approach can terminate
> (crash?) more gracefully. This doesn't actually work, but it
> could work in theory if someone rewrote the compiler and linker."

Your words indeed :-)

The availability of run-time information in the case of methods allows the BlackBox runtime to not fail at all -- e.g. to automatically reload erroneously unloaded modules or to request confirmation from the user/operator, etc.
Determining which modules can and cannot be unloaded appears to be similar to the problem of memory management.

This can easily get out of hand with web servers, embedded systems, and remotely controlled clusters (e.g. a very real possibility: the cluster may be in Edmonton, Alberta; I may be running my tasks on it from Troitsk, Moscow Region).

The difference between "crash more gracefully" and "never crash" in such situations, is great enough that the question merits discussion.

With BlackBox to be open-sourced very soon now, there will be more chances to make the necessary modifications.

> But this means that the user of the variable M.cube needs to
> check the exact declaration of the type M.Cube just to
> ascertain if the documentation search tool has a chance of
> finding the correct Docu/Source/Interface for the procedure
> M.Cube.Eval (I include interface because an extension may
> have narrowed the return type).
>
> There are no such subtleties to worry about with the function R.Cube.

I have not experienced problems with finding documentation about a specific exported variable like TextModels.dir.
I don't see why there should be any for M.cube.
It seems to me, the subtleties you pointed out are only important in rare cases.

Cheers
Fyodor

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Received on Sun Nov 28 2004 - 12:54:03 UTC