Re: Forward compatibility (was Re: [Haskell-cafe] GHCi infers a type but refuses it as type signature)
On Tue, Jun 23, 2009 at 8:28 PM, Brandon S. Allbery KF8NH allb...@ece.cmu.edu wrote: On Jun 23, 2009, at 05:20 , Luke Palmer wrote: obsolete now, will your code still work when they are gone? Will it still work when the typeclass resolution algorithm is obsoleted by a superior algorithm (I'm looking at you, Oleg! :-)? When Haskell is obsolete, how hard will it be to port? This is the point at which 99% of programmers throw up their hands at the futility of trying to guess what lies 20 years in the future, and just writes the fscking code. I mean, you've just ruled out both Haskell98 *and* Haskell-with-extensions. What? I didn't mean to. In case I wasn't clear enough, by the typeclass algorithm, I mean the algorithm for inference with typeclasses -- the semantics would be the same. Many of Oleg's famous hacks are sensitive to the specific way GHC searches for instances, which I did intend to rule out. And how hard will it be to port is about the essence of the code. I'm trying to rule out code which is not correct and meaningul at its heart, but which may rely on syntactic tricks (eg. printf emulation, Monads which don't satisfy the laws just for the notation, ...), or operational tricks such as unsafeInterleaveIO. Code that has an air of a mathematical model is much more likely to be portable. I think typical Haskell code will end up having a much longer life than typical C code, even if Haskell dies when C is still in use. But a small fraction Haskell code is *just* Haskell code, and I try not to write that kind. Really, such mindfulness is a lot easier than it sounds, because we are using such a beautiful, essentially simple language. Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Forward compatibility (was Re: [Haskell-cafe] GHCi infers a type but refuses it as type signature)
Hi Luke, Simple: the definition of MonadState uses those extensions. [Snip question: Is this extension supported by all compilers] You should treat all compilers the same way as a universal quantifier in mathematics. It's not just all the compilers you know about, but all possible compilers. In which case the answer to your question is of course no. I think the reasoninging here is the following: If MonadState is part of the standard library and it needs this extension to work, then all compilers must support this extension. I'm not completely sure how standard the MonadState class is though. Also, it might be that there could be implementations of MonadState that do not use the extension? If the latter is not the case, so MonadState will always require this extension, than it seems that using the extension in your code gives you the same portability as using the MonadState class. Not using the extension to improve your portability only makes sense if you also stop using the MonadState class, right? Gr. Matthijs signature.asc Description: Digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Forward compatibility (was Re: [Haskell-cafe] GHCi infers a type but refuses it as type signature)
On Jun 23, 2009, at 05:20 , Luke Palmer wrote: obsolete now, will your code still work when they are gone? Will it still work when the typeclass resolution algorithm is obsoleted by a superior algorithm (I'm looking at you, Oleg! :-)? When Haskell is obsolete, how hard will it be to port? This is the point at which 99% of programmers throw up their hands at the futility of trying to guess what lies 20 years in the future, and just writes the fscking code. I mean, you've just ruled out both Haskell98 *and* Haskell-with-extensions. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
