C++ functor to output iterator adapter
Date : March 29 2020, 07:55 AM

Defining a class with functorish and nonfunctorish functions
Date : March 29 2020, 07:55 AM
I hope this helps you . One possibility is to encode the "Container" type using another associated type. import qualified Data.Map.Lazy as M
class MyMap m where
type Key m
type Value m
type Container m :: * > *
keys :: m > [Key m]
elems :: m > [Value m]
mapify :: (a > b) > Container m a > Container m b
instance MyMap (M.Map k v) where
type Key (M.Map k v) = k
type Value (M.Map k v) = v
type Container (M.Map k v) = M.Map k
keys = M.keys
elems = M.elems
mapify = M.map
class MyMap m where
type Key m
type Value m
type Container m :: * > *
keys :: m > [Key m]
elems :: m > [Value m]
 mapify :: (a > b) > Container m a > Container m b
 Make sure the typechecker knows that m2 is just the container of m with
 a different value
mapify :: (MyMap m2, m2 ~ Container m (Value m2)) => (Value m > Value m2) > m > m2
instance MyMap (M.Map k v) where
type Key (M.Map k v) = k
type Value (M.Map k v) = v
type Container (M.Map k v) = M.Map k
keys = M.keys
elems = M.elems
mapify = M.map
doSomething
:: (MyMap m1, MyMap m2, m2 ~ Container m1 (Value m2)) =>
(Value m1 > Value m2) > m1 > m2
doSomething f m = mapify f m

Is it more efficient to make an functor with no members a class member object or a stack object?
Tag : cpp , By : Nickolas
Date : March 29 2020, 07:55 AM
should help you out For an empty object, just create it in the stack. Adding the functor to your type as a member will make all of your objects larger. Adding it as a base (to make use of the empty base optimization), will yield a weird design in which your type implements operator()(const MyData&) for no reason. Even if you make it private the operator will be there. Since the type has no members, there is no cache locality issues, as no data to be accessed. The main use of a stateless functor is to allow the compiler to inline the call to the function (compared with a free function with the same name)

Why can I not make a (Functor f) => ConcreteType > f String into an instance Functor ((>) ConcreteType)?
Date : March 29 2020, 07:55 AM
Hope this helps You've overspecialized. The definition of a functor is as follows: class Functor f where
fmap :: (a > b) > f a > f b

How to Make JTable in adapter class and calling it in main class
Tag : java , By : user103892
Date : March 29 2020, 07:55 AM

