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From: "Alejandro R. Mosteo" <alejandro@mosteo.com>
Newsgroups: comp.lang.ada
Subject: package organization (is this doable?)
Date: Fri, 29 Jun 2018 17:45:28 +0200
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Xref: reader02.eternal-september.org comp.lang.ada:53432
Date: 2018-06-29T17:45:28+02:00
List-Id: <comp.lang.ada>

So the problem: I'm binding a C library with several types/features that 
I'm splitting into several Ada packages. These packages must talk to each 
other sometimes in terms of auxiliary types that I want to hide from the 
user.

Even if I hide these types in a private package, or in the common parent 
private part, I cannot think of a way of exposing some subprograms in one 
package to the other, without also exposing them to users.

Example:

package Lib; -- Root package

package Lib.Feat_1; -- Some feature

package Lib.Feat_2; -- Another feature

private package Lib.Impl; -- Things I want to keep secret, conceptually 
they're in the private part of Lib IIUC.

Am I right that it is impossible for Feat_1 and Feat_2 to communicate 
using something that's private in Lib or Lib.Impl? That would mean 
exposing those private types in their respective public parts, which is a 
no go.

Right now I'm moving the things I don't want the user to see to a further 
child, e.g.:

Lib.Feat_1.Impl;
Lib.Feat_2.Impl;

There, implementation type names/subprograms are visible but the idea is 
that users never need these packages. And they can call each other. The 
thing is, I feel like I'm missing some way of organizing things to make 
what I want possible (that some types are never visible to the user). It 
feels like a diamond problem in that I need a child of two packages 
simultaneously (that could be entirely private).

Thanks,
Álex.