[Haskell-cafe] Re: Packages and modules

[Brian Hulley]

Simon Peyton-Jones wrote:
> In response to Brian and Ian's helpful comments, I've added a bunch
> more stuff to our proposal about packages.  If I have missed
> anything, let me know.
>
> http://hackage.haskell.org/trac/ghc/wiki/GhcPackages
>
> If you or anyone else thinks the choices made there are poor ones,
> continue to say so.  It's a helpful process.

I think the proposed system is too complicated. I'd have thought there were 
some simple aims:

1) Backwards compatibility so existing code doesn't break

2) Allow people to use per-package module namespaces in new code

3) Allow package names to be URLs (Marc Weber's idea 
http://www.haskell.org//pipermail/haskell-cafe/2006-June/016378.html )

And the following possible solutions:

1) The current "import" syntax would refer to shared namespace imports 
(exactly as at present)

2) A new keyword, "use", would indicate use of per-package namespaces

3) Putting the package name in quotes allows more complex package names 
including URLs and packages located in a specific folder etc in future, and 
also makes it clear that the package name is an OS filename (albeit 
conforming to a special form) not a Haskell id, and also allows the "use" 
syntax to be very concise since a quoted name cannot be confused with a 
modid.

So instead of just taking this simple solution, the wiki proposal is instead 
destroying the beauty of the per-package namespace idea by incorporating 
into it the existing shared namespaces with their attendant problems, 
instead of just letting the existing messy system die a natural death 
through the syntactic isolation I proposed.

In three years' time, how easy will it be to explain Haskell's module system 
to a new programmer?

Regards, Brian.
-- 
Logic empowers us and Love gives us purpose.
Yet still phantoms restless for eras long past,
congealed in the present in unthought forms,
strive mightily unseen to destroy us.

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