[Haskell-cafe] Definition of the Haskell standard library

[Duncan Coutts]

On Mon, 2007-07-30 at 09:19 -0600, Chris Smith wrote:
> Can someone clarify what's going on with the standard library in 
> Haskell?
> 
> As of right now, I can download, say, GHC from haskell.org/ghc and get a 
> set of libraries with it.  I can visit 
> http://haskell.org/ghc/docs/latest/html/libraries/, linked from the 
> haskell.org home page, and see descriptions of all of those libraries.  
> I can build with --make (or if I'm feeling masochistic, add several 
> lines of -package options) and it works.  That's all great.
> 
> I've seen some stuff lately on -libraries and this list indicating that 
> there's an effort to change this.  People asking whether something 
> should be included in the standard library are being told that there is 
> no standard library really.  I'm hearing that the only distinction that 
> matters is "used by GHC" or "not used by GHC", and that being on hackage 
> is as official as it gets.
> 
> Am I misunderstanding?
> Is there something awesome about Hackage that I'm not seeing?

It's not finished yet :-)

> I hope one of those two is the case.  Otherwise, there's a serious 
> mistake being made here.  Having a web site where people can download 
> any of hundreds of independent libraries is not the same thing as having 
> a good standard library for the language.  I don't want to see the day 
> when setting up Haskell involves a day-long effort of figuring out what 
> libraries to download and install from Hackage, and in what order to do 
> it to satisfy all the dependencies,

We have tools to solve the downloading and installing all deps problem.
It's called cabal-install. It's sort-of almost ready for wider testing.

>  and new Haskellers poring over web 
> sites for the thousandth time before realizing that so-and-so's GUI 
> library hasn't actually been touched since they finished their class 
> project in 1998 and doesn't build with the latest version of Qt or 
> whatever.

So, yes, at the moment hackage looks like a big list of packages, but
the tools for automatically downloading and installing will mature. Also
we expect further improvements to hackage to do more automated QA and
gather testing feedback, so we can detect and manage bitrot. People have
also been talking about gathering usage stats, so one can see which out
of a collection of packages in a similar area are most used. I'm sure
there are other ideas that can be borrowed from CPAN and similar things.

On the other hand, it's not entirely true that there's no standard
library, it's just that it's borders are slightly fuzzy. For example, we
do have the library change submission process for modifying the standard
libraries. Up until now that has been taken to mean changes to the base
package. That package is now being split up, so we'll have to think
about what it'll apply to in the future.

My opinion is that in the past it has been too difficult to get changes
into the base library, that there's been too much stability at the
expense of improving scope and quality. Making it easy to install new
packages and upgrade existing standard libraries should make it easier
to trial more major changes outside of the standard libs before
proposing getting those changes integrated.

Duncan