[Haskell] Re: RFC: DData in hierarchical libraries

[Christian Maeder]

Simon Marlow wrote:
>>Also, if the map argument comes first in 'insert 
>>map key x',

I find a type like ".. -> Bla -> Bla" more naturally for (right) folding

> oops, I don't really mean "inserting several things in the same map", I
> mean "looking up several keys in the same map", i.e. it makes sense for
> the map argument to lookup to come first.

A true argument, but it is inconsistent with `Set.member` and 
`List.elem` which can be used as sections. (This does not imply that I 
would like the key and value to be paired.)

Christian