[clean-list] Comments on the module system

[Marco Kesseler]

Hi Brian.

you wrote:
>I'm a strong proponent of nested modules, but I believe that simply
>having qualified imports would be a very useful, simple addition.  

and:
>I'm confused, I thought your question was about how to do this with Clean
>now, not how this would work in a hierarchical module system.

I am not wondering how to do this in Clean now. I agree very much 
that having some form of qualified names is very useful. I am just 
wondering what would be the best way to add them.

In short, I find two things important:
- being able to extend an existing namespace without touching 
existing modules.
- avoiding the problem of having to adjust all qualified references 
as soon as a definition moves to another module.

So, I have proposed to use something similar to C#/C++ namespaces, 
which meet these wishes. I think these are relatively easy to add to 
Clean's module system.

At the same time, I have been wondering whether Mercury and other 
languages meet both goals in other ways. Until now, it seems that 
they do not. The Java solution seems to come close, but has the 
problem that package names dictate the location of your sources, 
which makes it more intrusive to extend an existing namespace/package.

As to nested modules, I really have no opinion about these. I simply 
do not know (yet).

Thanks for the explanations by the way.

regards,
Marco