Quark v2.3.0 Quark.SKI View Source
The classic SKI
system of combinators. s
and k
alone can be used to express any algorithm,
though generally not efficiently.
Link to this section Summary
Functions
The identity combinator. Also aliased as id
See Quark.SKI.i/1
The constant (“Konstant”) combinator. Returns the first argument unchanged, and discards the second argument
The “substitution” combinator. Applies the last argument to the first two, and then the first two to each other
Opposite of first
(the k
combinator)
Link to this section Functions
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]
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
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
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)
[]