See Quark.SKI.k/2.

See Quark.SKI.k/2.

The identity combinator. Also aliased as id.

iex> i(1)
1

iex> i("identity combinator")
"identity combinator"

iex> [1,2,3] |> id
[1,2,3]

Specs

i(any()) :: any()

See Quark.SKI.i/1.

The constant ("Konstant") combinator. Returns the first argument unchanged, and discards the second argument.

Can be used to repeatedly apply the same value in functions such as folds.

Aliased as first and constant.

Examples

iex> k(1, 2)
1

iex> k("happy", "sad")
"happy"

iex> Enum.reduce([1,2,3], [42], &k/2)
3

iex> Enum.reduce([1,2,3], [42], &constant/2)
3

iex> first(1,2)
1

Specs

k(any(), any()) :: any()

The "substitution" combinator. Applies the last argument to the first two, and then the first two to each other.

Examples

iex> add = &(&1 + &2)
...> double = &(&1 * 2)
...> s(add, double, 8)
24

Specs

s((... -> any()), (... -> any()), any()) :: any()

Opposite of first (the k combinator).

While not strictly part of SKI, it's a common enough case.

Returns the second of two arguments. Can be used to repeatedly apply the same value in functions such as folds.

Examples

iex> second(43, 42)
42

iex> Enum.reduce([1,2,3], [], &second/2)
[]

Specs

second(any(), any()) :: any()