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retired
A standard library for the Gleam programming language
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src/gleam/pair.gleam
/// Returns the first element in a pair.
///
/// ## Examples
///
/// > first(#(1, 2))
/// 1
///
pub fn first(pair: #(a, b)) -> a {
let #(a, _) = pair
a
}
/// Returns the second element in a pair.
///
/// ## Examples
///
/// > second(#(1, 2))
/// 2
///
pub fn second(pair: #(a, b)) -> b {
let #(_, a) = pair
a
}
/// Returns a new pair with the elements swapped.
///
/// ## Examples
///
/// > swap(#(1, 2))
/// #(2, 1)
///
pub fn swap(pair: #(a, b)) -> #(b, a) {
let #(a, b) = pair
#(b, a)
}
/// Returns a new pair with the first element having had `with` applied to
/// it.
///
/// ## Examples
///
/// > #(1, 2) |> map_first(fn(n) { n * 2 })
/// 2
///
pub fn map_first(of pair: #(a, b), with fun: fn(a) -> c) -> #(c, b) {
let #(a, b) = pair
#(fun(a), b)
}
/// Returns a new pair with the second element having had `with` applied to
/// it.
///
/// ## Examples
///
/// > #(1, 2) |> map_second(fn(n) { n * 2 })
/// 4
///
pub fn map_second(of pair: #(a, b), with fun: fn(b) -> c) -> #(a, c) {
let #(a, b) = pair
#(a, fun(b))
}