From: "Shae Matijs Erisson - [EMAIL PROTECTED]" Sent: Tuesday, December 06, 2005 6:16 PM
> [EMAIL PROTECTED] writes: > > > being occupied with learning both languages, I'm getting curious if > > Haskell couldn't achieve most of the performance gains resulting from > > uniqueness typing in Clean by *automatically* determining the reference > > count of arguments wherever possible and subsequently allowing them to > > be physically replaced immediately by (the corresponding part of) the > > function's result. Are there any principal obstacles, or *could* this be > > done, or *is* this even done already, e. g. in ghc? > > Maybe you're describing speculative evaluation? > > Optimistic Evaluation: An Adaptive Evaluation Strategy for Non-Strict Programs > http://citeseer.ist.psu.edu/ennals03optimistic.html > -- Thanks for the pointer - I have heard a little about optimistic evaluation already, but don't know much of the details (yet). Anyway, from what I know, I think it's a different thing. In Clean, you can (and often are required to) assign uniqueness attributes to some parts of a function's type signature. The extended type checker ensures that none of those parts is referred to more than once during a single run of the program. Based on this guarantee, a function does not have to allocate new memory at all to store a unique result but can overwrite the unique arguments in place. Apparently, the uniqueness assignments have to comply with very tight laws - getting a program through the Clean type checker can be tough, once it reports an uniqueness coercion error. I suppose, no explicit uniqueness attributing is going to be implemented in Haskell, anyway. My question is - and this might better suit to Haskell -, can't uniqueness be inferred (and exploited) automatically in many cases? Regards, zooloo -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.371 / Virus Database: 267.13.12/192 - Release Date: 05.12.2005 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
