From 032f840e212f82f9b940fe75cdd4789db9aa2ba2 Mon Sep 17 00:00:00 2001
From: Marcin Puc <marcin.e.puc@gmail.com>
Date: Sun, 14 Mar 2021 20:35:28 +0100
Subject: Add {iterator, list}.last

---
 src/gleam/iterator.gleam | 17 +++++++++++++++++
 src/gleam/list.gleam     | 17 +++++++++++++++++
 2 files changed, 34 insertions(+)

(limited to 'src')

diff --git a/src/gleam/iterator.gleam b/src/gleam/iterator.gleam
index fa49b87..499cd92 100644
--- a/src/gleam/iterator.gleam
+++ b/src/gleam/iterator.gleam
@@ -946,3 +946,20 @@ pub fn reduce(
       |> Ok
   }
 }
+
+/// Returns the last element in the given iterator.
+///
+/// Returns `Error(Nil)` if the iterator is empty.
+///
+/// ## Examples
+///
+///    > from_list([]) |> last
+///    Error(Nil)
+///
+///    > range(1, 10) |> last
+///    Ok(9)
+///
+pub fn last(iterator: Iterator(element)) -> Result(element, Nil) {
+  iterator
+  |> reduce(fn(elem, _) { elem })
+}
diff --git a/src/gleam/list.gleam b/src/gleam/list.gleam
index 9f88063..f99b729 100644
--- a/src/gleam/list.gleam
+++ b/src/gleam/list.gleam
@@ -1431,3 +1431,20 @@ pub fn scan(
 ) -> List(b) {
   do_scan(list, initial, [], fun)
 }
+
+/// Returns the last element in the given list.
+///
+/// Returns `Error(Nil)` if the list is empty.
+///
+/// ## Examples
+///
+///    > last([])
+///    Error(Nil)
+///
+///    > last([1, 2, 3, 4, 5])
+///    Ok(5)
+///
+pub fn last(list: List(a)) -> Result(a, Nil) {
+  list
+  |> reduce(fn(elem, _) { elem })
+}
-- 
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