A proposal for `system' imports

[Denys Duchier]

schulte at comp.nus.edu.sg (Christian Schulte) writes:

> Whatever you do, unqualified names will be a problem.

On the contrary.  My proposal makes the meaning very clear, unlike the
current situation.  A naked import would ALWAYS name a module in the
x-oz:/system namespace.

> We should not waste time on replacing one solution with drawbacks by
> another one.

The only drawback is non-backward compatibility.  The overwhelming
advantage is backwards compatibility from then on while permitting
growth of the standard library.  With the current scheme, adding a
system module may break existing programs.  With my proposal, (1) this
is no longer the case, (2) the logic for resolving naked imports
becomes extremely simple (and easy to explain).

> The current solution allows easier first-time exposure to modules,
> and this is in my viewpoint a very strong argument.

Wrong, it doesn't.  Explaining naked imports is hard: sometimes it
means this, sometimes it means that, and it's not guaranteed to
continue to mean the same thing in the future.  That's just bogus.  My
proposal makes it easier to explain: for convenience, you don't have
to supply the `at' clause for modules in the standard library.

> So I am very much against this, in addition please consider that
> changing everything (module manager, linker, all the docs, many
> programs) will inevitebly introduce bugs.

I am well aware that the transition will be bumpy, but I believe that
it is necessary in order to accommodate naturally the idea of a
growing standard library.  It's also a simplification both conceptual
and implementational.

Cheers,

-- 
Dr. Denys Duchier			Denys.Duchier at ps.uni-sb.de
Forschungsbereich Programmiersysteme	(Programming Systems Lab)
Universitaet des Saarlandes, Geb. 45	http://www.ps.uni-sb.de/~duchier
Postfach 15 11 50			Phone: +49 681 302 5618
66041 Saarbruecken, Germany		Fax:   +49 681 302 5615
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