I agree with Neil. Translators are very difficult to do right, except for
the most trivial transformations.
Changing tabs to spaces is about as far as I would trust an automatic
translator.
-- Lennart
On Thu, Apr 24, 2008 at 9:21 AM, Neil Mitchell
Hi
I think Henrik's criteria are pretty close to perfect.
As I have argued before on the committee list, I also think we should *not* worry about backwards incompatible changes too much in cases where a simple automatic translation from H98 to H' code is possible. Even for a large project, it is IMHO no big hardship to run a H98->H' translator over all Haskell sources.
Some questions:
1) Will I (the programmer) have to mode switch in painful ways between H98 and H'? Do I have to learn a pile of exceptions, or is there some common rule that works? (i.e. removing n+k is fine since I just don't learn it, changing the fixity of $ is not since I need to know both)
2) Will tool T (the translator) work on academic papers that have previously been published.
3) Will tool T handle all of GHC's extensions.
4) Will tool T deal with things like CPP, hsc, trhsx, happy, alex etc... - all these file formats which include embedded Haskell.
5) Will tool T ever exist.
I think the answer to 2-5 is nearly certainly going to be "No". I don't think the relevance of a conversion tool should even be considered until some person steps forward and says without doubt that _they_ will write the converter. Even if they did there very best, it still won't be trivial to use in all cases.
As John Launchbury has said, given Haskell's current rise in popularity, anything that we do not fix with H' will be much harder, if not impossible, to fix in the future.
That is a very good point. Perhaps we're already a little too late.
Thanks
Neil _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime