Quark v1.0.1 Quark.Compose
Function composition is taking two functions, and joining them together to create a new function. For example:
iex> sum_plus_one = compose([&(&1 + 1), &Enum.sum/1])
iex> sum_plus_one.([1,2,3])
7
In this case, we have joined Enum.sum with a function that adds one, to create
a new function that takes a list, sums it, and adds one.
Note that composition normally applies from right to left, though Quark
provides the opposite in the form of *_forward functions.
Summary
Functions
Infix compositon operator
Function composition, from the tail of the list to the head
Function composition
Function composition, from the back of the lift to the front
Compose functions, from the head of the list of functions. The is the reverse order versus what one would normally expect (left to right rather than right to left)
Functions
Specs
(... -> any) <|> (... -> any) :: (... -> any)Infix compositon operator
iex> sum_plus_one = fn x -> x + 1 end <|> &Enum.sum/1
iex> sum_plus_one.([1,2,3])
7
iex> add_one = &(&1 + 1)
iex> piped = [1,2,3] |> Enum.sum |> add_one.()
iex> composed = [1,2,3] |> ((add_one <|> &Enum.sum/1)).()
iex> piped == composed
true
Specs
compose([(... -> any)]) :: (... -> any)Function composition, from the tail of the list to the head
iex> sum_plus_one = compose([&(&1 + 1), &Enum.sum/1])
iex> [1,2,3] |> sum_plus_one.()
7
Specs
compose((... -> any), (... -> any)) :: anyFunction composition
iex> sum_plus_one = compose(&(&1 + 1), &Enum.sum/1)
iex> [1,2,3] |> sum_plus_one.()
7
Function composition, from the back of the lift to the front
iex> sum_plus_one = compose_forward(&(Enum.sum(&1)), &(&1 + 1))
iex> [1,2,3] |> sum_plus_one.()
7
Compose functions, from the head of the list of functions. The is the reverse order versus what one would normally expect (left to right rather than right to left).
iex> sum_plus_one = compose_list_forward([&Enum.sum/1, &(&1 + 1)])
iex> [1,2,3] |> sum_plus_one.()
7