Re: [Haskell-cafe] An easy way to represent and modify graphs?
On 21/09/2012, Takayuki Muranushi muranu...@gmail.com wrote: Yes Pointers. I've forgotten that. I have once dealt with structures, with lots of IORefs. It was smooth and fast. Thank you for reminding me! On the other hand, use of pointers means that our values are not algebraic data type any more. We have to derive operations such as map, fold, serialize by ourselves. I can do that, but am I right? Or is there some systematic way to derive such operations? If you mean that one can't write deriving (Class, ...) then yes, to my knowledge, one can't, as it would not know to follow the pointers. I doubt that such a derivation algorithm would be possible in general, since it wouldn't know whether to compare by value, i.e. follow the pointer. Best regards, Takayuki Cheers, Strake ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An easy way to represent and modify graphs?
Yes Pointers. I've forgotten that. I have once dealt with structures, with lots of IORefs. It was smooth and fast. Thank you for reminding me! On the other hand, use of pointers means that our values are not algebraic data type any more. We have to derive operations such as map, fold, serialize by ourselves. I can do that, but am I right? Or is there some systematic way to derive such operations? Best regards, Takayuki ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An easy way to represent and modify graphs?
Pointers. Seriously. In Haskell one could use STRef rather than the cumbersome Foreign.Ptr, though STRef too can be kludgy. I know not whether safe, pure, immutable pointers would be possible in Haskell, but in my experience STRef can work well enough. Cheers, Strake ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
