haskell,monads,function-composition

Let's start step by step. Misty typeclass is given: class Misty m where banana :: (a -> m b) -> m a -> m b unicorn :: a -> m a Also furry' is already solved in an earlier problem in those exercises: furry' :: Misty m => (a ->...

In terms of order of operations, Haskell generally goes: Parentheses, Function Applications, Operators, Special Forms. So fact 8 + case h (f 3 + g 1) of Nothing -> 2 will parse as: (+) fact 8 case h (+) f 3 g 1 Nothing 2 with both the f and...

python,function,monkeypatching,function-composition

You can use your hack class as a decorator pretty much as it's written, though you'd likely want to choose a more appropriate name for the class. Like this: class Composable(object): def __init__(self, function): self.function = function def __call__(self, *args, **kwargs): return self.function(*args, **kwargs) def __mul__(self, other): @Composable def composed(*args,...

First of all, there's a mistake in your [original, unedited] question: h = f . g is equivalent to h x = g(f x) — that's not true: h = f . g is equivalent to h x = f (g x). However, as to why it's that way and...

haskell,functional-programming,function-composition

I understand how you feel. I found function composition to be quite difficult to grasp at first too. What helped me grok the matter were type signatures. Consider: (*) :: Num x => x -> x -> x (+) :: Num y => y -> y -> y (.) ::...

java,eclipse,java-8,function-composition,method-reference

As Brian Goetz (project lead for Java lambdas) says, "Lambda expressions have no intrinsic type" (which applies to method references too). This is why you need to cast (or assign) to type Function before its methods become available. The reason Eclipse shows different error messages from the JDK compiler (javac)...

Here is what I managed to do, but was not sure it is the easiest way, since I use dependent type and dependent pattern matching to encode the family g1, ... , gn: Require Import NaryFunctions Vector. Open Scope type. First I need a function to apply a function f:...

haskell,io,function-composition

Function application binds more tightly than (.) so sequence . take 5 . cycle [getRect] is the same as sequence . take 5 . (cycle [getRect]) since cycle [getRect] is list and not a function you get the error. You can use parentheses to get the precedence you want: rectangles...

The problem here is that map is not locked-down enough – what kind of collection is A? You can’t write a generic function that generates a generic function – when you call it, the types of all the placeholders have to be fully determined. This means you can call your...

I do not see a way of using ($) and (.) in this code. However, you can simplify your code as this: compress :: [Char] -> [Char] compress [] = [] compress [email protected](x:xs) | g as 1 == 1 = x : compress xs | otherwise = x : show...

You just need an extra dot: return . transformContent . TaggedContent (id, attrs) =<< readFile f ...

clojure,functional-programming,higher-order-functions,function-composition

To see your problem with (reduce compose-filters ... let's look a bit at what that actually does. First, it uses filter on the first two predicates and composes them.. The result of that is a new function from sequences to sequences. The next iteration then calls filter on that function,...

haskell,function-composition,arrows,category-theory

As Hackage and/or Hoogle will tell you, (>>>) :: Category k => a`k`b -> b`k`c -> a`k`c (<<<) :: Category k => b`k`c -> a`k`b -> a`k`c Observe that the latter is actually the same as (.) :: Category k => b`k`c -> a`k`b -> a`k`c or, in its Prelude...