Re: Hiding a type

["Pat Rogers" <progers@classwide.com>]

"Ryan Tarpine" <rtarpine@hotmail.com> wrote in message
news:3D27263F.7070101@hotmail.com...
> Hello everyone!  I have just started learning Ada, and I am trying to
> use it on my next (personal) project.  That's generally how I learn
> things, by jumping in too deep (It worked to teach myself OCaml, so
> we'll see how this turns out! :)

Do check out a textbook from the library -- it is worth the time -- or
take one of the on-line tutorials.  See www.adapower.com.

> What I'm wondering is how to hide a private type under a different,
> public name so variables can't be assigned.  I'm not sure how to say
it
> best, so here's the simplest example of it:

<snip>

> I want to write functions that will return something of type Hide in a
> way so clients can't do anything except pass it to other functions.  I
> also don't want them to know if I change how I implement it.  (In my
> real program, I'm trying to hide that Foo returns an access type.)
> Please tell how I should actually do this

package Opaque is
    type Hidden is limited private;
    -- declare the operations here that you want to export to clients
private
    type Hidden is access all Integer;
end Opaque;


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