[Haskell] Read Instances for Data.Map and Data.Set

Johannes Waldmann waldmann at imn.htwk-leipzig.de
Fri Oct 21 05:39:16 EDT 2005

Bulat wrote:

> parameterized modules will be a good solution for all those problems.
> or ability to hide/import class instances, not only plain functions:

I see that would work around the problem. But still this does not smell
right. If we have to hide something, this indicates that it shouldn't
have been there (or been visible) in the first place.

Yes, I think hiding identifiers is bad style as well.
This only comes up because we're too lazy to write out qualified names.
Again this could be helped by bringing imported modules into scope
locally:  let { import Foo.Bar ; ... }

This seems to me like a small extension with obvious semantics.
But I might be missing something, perhaps related to the scope of class
instances that get imported. Well then, let them have full (module) scope.

respectfully submitted,
-- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 --
---- http://www.imn.htwk-leipzig.de/~waldmann/ -------

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