Haskell report (August release)
Thu, 27 Sep 2001 12:34:59 -0700
Here's a minor quibble with the organization of the Report and Library,
not with the content. Sorry if this has been brought up before.
In section 4.3.3, Derived Instances, of the Report there is
The only classes in the Prelude for which derived instances are
allowed are Eq, Ord, Enum, Bounded, Show, and Read, all mentioned in
Figure 5, ... Classes defined by the standard libraries may also be
In the introduction to the Library Report there is
Classes defined in libraries may be derivable. This report includes
the derivation of such classes when appropriate.
Now, unless I missed something, the only class in the Library Report
which is derivable is Ix.
I would argue for bringing the Ix class into the Report for these reasons
* One does not have to search through the Library Report to determine
what is derivable.
* I think one would expect that the Libraries contain stuff that could be
implemented in Haskell by the user. Until Haskell has the ability
to allow for user-defined derivable classes, Ix cannot be
defined by the user.