I would like to store some objects from different type hierarchy into List[Any] or similar container, but perform implicit conversions on th开发者_Python百科em later on to do something like type class
haskell programmer. using F#. no typeclasses in F#. what to use when I need t开发者_运维知识库ypeclasses?Do check out this as someone suggested.
I\'m reading Learn You a Haskell and I\'m wondering why so many things are acting like a list, and nothing in the Pr开发者_Go百科elude is using the native facility of type classes to set this up:
I\'m playing around in Haskell to try and get the hang of it. I\'m running into problems with my typeclasses. What I\'m trying to do is to make a generalized a* module by defining classes and methods
I have defined the f开发者_如何学运维ollowing module to help me with FFI function export: {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, TypeSynonymInstances #-}
If I write foo :: (Num a) => a foo = 42 GHC happily accepts it, but if I write bar :: (Num a) => a bar = (42 :: Int)
In chapter 15 of Rea开发者_如何学Pythonl World Haskell, a type class is defined: class (Monad m) => MonadSupply s m | m -> s where
I\'m trying to get the following code to compile import IO data MyInt = MyInt Int data MyString = MyString String deriving Show
I wish to say开发者_StackOverflow that a certain parametrized monad st works with a regular memory, but a subclass of my parametrized monad should impose an additional constraint on the type of memory
In order to grasp better typeclasses (starting pretty much form scratch) I had a go at modelling 2-D shapes with area calculations, like this: