nstance Read (F a) where read str= eval str >>= F str sorry
2010/11/11 Alberto G. Corona <agocor...@gmail.com> > There are some straighforward tricks using the package eval (or hint)l. > > This is more or less the idea in pseudocode: > > type FuncExpr= String > > data F a = F FuncExpr a > > apply (F _ f) x= f x > > instance Show (F a) where show (F str _)= str > > instance Read (F a) where read (F str f)= eval f >>= F str > > > > 2010/11/11 Jesse Schalken <jesseschal...@gmail.com> > >> Is it possible to serialize and deserialize a function to/from binary >> form, perhaps using Data.Binary, for example? What about an IO action? If >> so, is there a way the serialized representation could >> be architecture-independent? >> >> I have been shown how useful it can be to store functions inside data >> structures, and while looking at data serialization for the purpose of >> persistence I wondered "since functions are just values in Haskell, why >> can't we persist them, too?". >> >> To me the idea has interesting implications. For example, an arbitrary >> program could simply be represented by a serialization of `IO ()`. In fact, >> you could load any program into memory from a file and use >> Control.Concurrent.forkIO to run it, and later kill it, giving you the >> beginnings of an operating environment. If such a serialization >> is architecture independent then to my understanding you have the beginnings >> of a virtual machine. You could break your program into pieces and store >> them in a database and load them when needed, or even pull updates to each >> piece individually from down the web etc, enabling interesting methods of >> software distribution. It would make very cool stuff possible. >> >> I have had a look at hs-plugins, but it is unclear how to derive a simple >> pair of functions `(a -> b) -> ByteString` and `ByteString -> Either >> ParseError (a -> b)`, for example, from the functionality it provides, if it >> is possible at all. I guess such a thing requires thorough digging into the >> depths of GHC, (or maybe even LLVM if >> an architecture independent representation is sought, but I don't know >> enough to say.). Perhaps this is more a question for those interested and >> knowledgable in Haskell compilation (and, to some extent, decompilation). >> >> If not Haskell, are there any languages which provide a simple >> serialization and deserialization of functions? >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe@haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe >> >> >
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
