Export String from Data.String

Proposals

This ticket makes three proposals, in order of importance IMHO:

1. Export String from Data.String. Most modules in base and on Hackage of the form: Data.<type> also export <type>. I think it's surprising and confusing that Data.String doesn't conform to this pattern.
2. Unexport String from Data.Char. I feel less strongly about this one, but in general I think it is good that a symbol is exported from as few modules as possible.
3. Export the String operations: lines, words, unlines and unwords from Data.String. I feel even less strongly about this one. However these are operations on Strings so it makes sense to export them from Data.String. As a counter argument you could say these operations either receive or produce a list of Strings so they only belong in Data.List.

If we accept 3 then in the spirit of export a symbol from as few modules as possible, you may expect a fourth proposal: Unexport the String operations: lines, words, unlines and unwords from Data.List. However I think this will break lots of programs. I have no problem also discussing this one though.

Attached is a patch bundle with three patches that implement the three proposals. We may end up deciding to apply only a few of them.

Discussion deadline

3 weeks from now: Wednesday 10 November.

Trac metadata

Trac field	Value
Version	6.12.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	libraries/base
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