Re: How to hide type internals

["Gerd" <GerdM.O@t-online.de>]

Stephen Leake schrieb:

> "Gerd" <GerdM.O@t-online.de> writes:
>
> > I would like to write a package that exports functions using a special
> > type, without showing the details in the spec (even not in the private
> > part).
>
> Others have shown how to do this.
>
> But I'd like to understand _why_ you want to do this.

There are at least two reasons:

If the definition is left to the body, a change of the definition needs
only a recompilation of the body. If the full type is declared within
the spec, you would have to recompile .all. packages that "with" this
spec. Otherwise it would be enough to provide a compiled object-file
with the spec.

First this is a question of compile time (large system), second this
would give the contractor a look into your internals. The first is a
simple thing of money, the second is a security decision (e.g. if the
"user" of this package has no clearance).