[Haskell] URLs in haskell module namespace

S. Alexander Jacobson alex at alexjacobson.com
Tue Mar 22 14:56:40 EST 2005

On Tue, 22 Mar 2005, Lemmih wrote:
> The idea with Hackage was to create a central place for people to put
> software or links to software, so keeping only one server for free (as
> in beer) packages would be desirable. However, this does in no way
> limit how Hackage can be used for private code repositories.

So I assume that means you also think we need a way to locate packages 
on various repositories.  Would you agree that URLs would be a good 
way of doing so?

>> And, if there are multiple hackage servers, we are going to need to
>> indentify the server from which a particular package originates and
>> the location of that package on that server.  This proposal provides
>> an obvious method of doing so.
> Specifying sources on the cmd line or in /etc/cabal/sources.list
> sounds more maintainable to me.

Except you then need to notice when you are no longer using a 
particular package and do bookkeeping.  You also have no way of saying 
that one of your modules is using version X of a package while another 
is using version Y without command line specification.

>> If module names were with respect to packages that would be entirely
>> fine.  But right now module names are global and that is a serious
>> problem.
> But they are! GHC can even handle several versions of the same
> package. Modules from a package wont be in scope if you hide or ignore
> it.

But suppose you want to use two different verions of the same package 
in a single module....Perhaps because you need to read a file saved 
with a show corresponding to an old version into a data structure 
defined in the new version...

S. Alexander Jacobson tel:917-770-6565 http://alexjacobson.com

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