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