Haskell 2010: libraries

Ian Lynagh igloo at earth.li
Tue Jul 14 08:57:34 EDT 2009

On Tue, Jul 14, 2009 at 12:23:51PM +0100, Duncan Coutts wrote:
> On Tue, 2009-07-14 at 00:20 +0100, Ian Lynagh wrote:
> > On Mon, Jul 13, 2009 at 09:56:50PM +0100, Duncan Coutts wrote:
> > > 
> > To take one example, since List was immortalised in the H98 report with
> > 104 exports, Data.List has gained an additional 7 exports:
> >
> > The last change (making the behaviour of the generic* functions
> > consistent with their non-generic counterparts) was less than a year
> > ago, and the last additions were less than 2.
> Though also note that we have not changed any of the existing ones.

Yes we have, less than a year ago:

GHCi, version 6.8.2: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
Prelude> Data.List.genericTake (-1) "abc"
"*** Exception: List.genericTake: negative argument

GHCi, version 6.10.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer ... linking ... done.
Loading package base ... linking ... done.
Prelude> Data.List.genericTake (-1) "abc"

> Is there a problem with specifying in the libraries section of the report
> that the exports are a minimum and not a maximum?

We wouldn't be able to fix the generic* functions, or the way exceptions

> > But to me, the most compelling argument for dropping them from the
> > report is that I can see no benefit to standardising them as part of the
> > language, rather than in a separate "base libraries" standard.
> Some functions, especially the pure ones are really part of the
> character of the language

The Haskell language could be thought of as being composed of "Haskell
Language 2010 report" and "Haskell Libraries 1.0 report".

> (and some are specified as part of the
> syntax)

Yes, some types functions may need to be specified by the report as
being somewhere for desugaring etc. Although maybe we could even
eliminate most of these if rebindable syntax became part of the


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