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build/dev/javascript/gleam_stdlib/gleam/pair.mjs

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+/**
+ * Returns the first element in a pair.
+ *
+ * ## Examples
+ *
+ * ```gleam
+ * first(#(1, 2))
+ * // -> 1
+ * ```
+ */
+export function first(pair) {
+  let a;
+  a = pair[0];
+  return a;
+}
+
+/**
+ * Returns the second element in a pair.
+ *
+ * ## Examples
+ *
+ * ```gleam
+ * second(#(1, 2))
+ * // -> 2
+ * ```
+ */
+export function second(pair) {
+  let a;
+  a = pair[1];
+  return a;
+}
+
+/**
+ * Returns a new pair with the elements swapped.
+ *
+ * ## Examples
+ *
+ * ```gleam
+ * swap(#(1, 2))
+ * // -> #(2, 1)
+ * ```
+ */
+export function swap(pair) {
+  let a;
+  let b;
+  a = pair[0];
+  b = pair[1];
+  return [b, a];
+}
+
+/**
+ * Returns a new pair with the first element having had `with` applied to
+ * it.
+ *
+ * ## Examples
+ *
+ * ```gleam
+ * #(1, 2) |> map_first(fn(n) { n * 2 })
+ * // -> #(2, 2)
+ * ```
+ */
+export function map_first(pair, fun) {
+  let a;
+  let b;
+  a = pair[0];
+  b = pair[1];
+  return [fun(a), b];
+}
+
+/**
+ * Returns a new pair with the second element having had `with` applied to
+ * it.
+ *
+ * ## Examples
+ *
+ * ```gleam
+ * #(1, 2) |> map_second(fn(n) { n * 2 })
+ * // -> #(1, 4)
+ * ```
+ */
+export function map_second(pair, fun) {
+  let a;
+  let b;
+  a = pair[0];
+  b = pair[1];
+  return [a, fun(b)];
+}
+
+/**
+ * Returns a new pair with the given elements. This can also be done using the dedicated
+ * syntax instead: `new(1, 2) == #(1, 2)`.
+ *
+ * ## Examples
+ *
+ * ```gleam
+ * new(1, 2)
+ * // -> #(1, 2)
+ * ```
+ */
+export function new$(first, second) {
+  return [first, second];
+}