On Wed, 2010-10-20 at 22:19 +0200, Bas van Dijk wrote:
Hello,
I would like to make 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.
Seems reasonable.
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.
Again, seems reasonable and you say not too many package break.
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.
I agree. We did this for the ByteString modules, we have Data.ByteString[.Lazy] and Data.ByteString[.Lazy].Char8. Only the latter ones export the functions that depend on the ASCII encoding. These four are the only functions in Data.List that specialise the [a] to [Char].
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.
Yeah, I agree in principle, but probably best to leave that for later. Duncan