A curried function takes its arguments one at a time:
> sum 3 4 7
An uncurried function takes its arguments in a tuple:
> sum (3, 4) 7
Write a function curry that converts an uncurried
function of two arguments to a curried function, and a function
uncurry that performs the inverse transformation.
Write
a function iterate f x that returns an
infinite list of repeated applications of f to x:
> take 10 (iterate (*2) 1) [1,2,4,8,16,32,64,128,256,512]
Write a function sortOn f list that
sorts a list by applying a key function to each element:
> sortOn length ["one", "two", "three", "four", "five", "six"] ["one","two","six","four","five","three"]
As in this example, the sort should be stable: elements with the same key value should keep their relative order.
Write a function altMap that takes
two functions and a list. altMap should apply the two
functions alternately to list elements. For example:
altMap (\i ->
i + 1) (\i -> i - 1) [1..8] == [2, 1, 4, 3, 6, 5, 8, 7]