the sequencing matters for applicative functors. from McBride and Patterson [1]:
"The idea is that 'pure' embeds pure computations into the pure fragment of an effectful world -- the resulting computations may thus be shunted around freely, as long as the order of the genuinely effectful computations is preserved." it is interesting to note that sequencing only matters a little for k-CAS : you just have to read before you write, but you can do the reads and writes in any order (as long as it is ultimately atomic.) b [1] McBride C, Patterson R. "Applicative programming with effects" Journal of Functional Programming 18:1 (2008), pages 1-13. On Apr 20, 2012, at 4:41 PM, KC wrote: > Sorry, I thought you or someone was asking why are Applicative Functors > faster in general than Monads. > > Functional programming is structured function calling to achieve a result > where the functions can be evaluated in an unspecified order; I thought > Applicative Functors had the same unspecified evaluation order; whereas, > Monads could carry some sequencing of computations which has the extra > overhead of continuation passing. > > Do I have that correct? > > > On Fri, Apr 20, 2012 at 4:05 PM, Ben <midfi...@gmail.com> wrote: > i'm not sure what your email is pointing at. if it is unclear, i understand > the difference between applicative and monadic. i suppose the easy answer to > why applicative can be faster than monadic is that you can give a more > specialized instance declaration. i was just wondering if there was a way to > make a monad recognize when it is being used applicatively, but that is > probably hard in general. > > b > > On Apr 20, 2012, at 2:54 PM, KC wrote: > > > Think of the differences (and similarities) of Applicative Functors and > > Monads and the extra context that monads carry around. > > > > > > -- > > -- > > Regards, > > KC > > > > > -- > -- > Regards, > KC _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
