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

[Malcolm Wallace]

Georg Martius <mai99dgf at studserv.uni-leipzig.de> writes:

> I was really annoyed by the fact that for Data.Map and Data.Set are no Read 
> instances declared, but Show instances are! I believe there should be some 
> kind of unwritten rule that in the standart lib the Show and Read instances 
> come pairwise and are fully compatible. 

FWIW, earlier versions of Haskell had a single class Text with
methods for both showing and reading, so it was harder to ignore
their complementary roles.

Regards,
    Malcolm