[m-dev.] module system discussion

[Tyson Dowd]

On 26-Nov-2001, Peter Ross <peter.ross at miscrit.be> wrote:
> Simon wrote:
> > 2. `:- transparent_module' and `:- include_transparent_module'
> > (we can probably do better on the names)
> >
> > `:- transparent_module' is a new variant of the `:- auto_import'
> > proposal, suggested by Tyson.
> >
> > A transparent sub-module is defined using a `:- transparent_module'
> > declaration rather than a `:- module' declaration, or included
> > using an `:- include_transparent_module' declaration. A transparent
> > sub-module is always _used_ when the parent module is imported or
> used.
> >
> > This is useful for qualifying the methods of typeclasses with the
> class
> > name without having explicitly to import the module (and lots of
> similar
> > ones) everywhere, and without having to import the entire hierarchy
> with
> > `:- use_hierarchy'.
> >
> > I think Fergus was still a bit wary about this one.
> >
> I can imagine situations where this would be useful, however
> import_hierarchy is sufficient for my needs.

I thought it would be very useful for all those little subclasses that
one needs to create in order to map a bunch of classes in a namespace
into a mercury module.

Each of these little subclasses could be put inside a transparent
subclass.  That way if you imported or used the parent module (say,
System__Data) you would get all the transparent submodules automatically
"used".

So we can still use submodules to get around the possible problems with
overloading (the submodules still introduce a new namespace) but you
don't need to write any extra import/use statements.

Of course you can get around writing import/use statement with
import_hierarchy/use_hierarchy, but this also has the effect of
importing non-transparent sub-modules (such as what we map .NET
namespaces into).

-- 
       Tyson Dowd           # 
                            #  Surreal humour isn't everyone's cup of fur.
     trd at cs.mu.oz.au        # 
http://www.cs.mu.oz.au/~trd #
--------------------------------------------------------------------------
mercury-developers mailing list
Post messages to:       mercury-developers at cs.mu.oz.au
Administrative Queries: owner-mercury-developers at cs.mu.oz.au
Subscriptions:          mercury-developers-request at cs.mu.oz.au
--------------------------------------------------------------------------