Sittampalam, Ganesh:
Manuel Chakravarty wrote:
We should be careful about where we break existing code, and we should try to support automatic translation of H98 to H' code, but any changes that we do not make now will become even more difficult in the future when there is even more Haskell code. Look at what is happening now already, industrial users applying pressure on the committee to not change the language too much for the sake of legacy code. A clear indication that anything we don't change now, we will have to live with forever.
I wasn't arguing for special treatment as an "industrial" user, just listing one datapoint that I have to counter any impression that the only or main cost to the community as a whole is fixing what's on hackage.
I agree with that. However, maybe somewhat paradoxically, I think, given the resistance that changes to the language already invoke now, we should actually be fairly aggressive with changes this one time (ie, in Haskell').
Hence, anything that is *important* to change, we should change now.
Agreed. It's just in this case the pain of changing will be huge and the benefits marginal at best.
Yes, I was not arguing for that particular change, my comment was of a general nature.
We should mitigate the pain by having a H98 to H' translator
Such a translator would have to maintain existing layout etc, and produce reasonably nice looking code in places where it makes changes. Do we have any infrastructure that would make writing one easy?
For H98, simple[1] changes might be possible with haskell-src if it would be modified to be able to preserve comments and layout. Manuel [1] For example, purely syntactic ones.