From fdf7145a92a4be1e9780372b8de5c4770ee06d33 Mon Sep 17 00:00:00 2001
From: Peter <peterhsaxton@gmail.com>
Date: Fri, 14 Aug 2020 08:50:36 +0100
Subject: test and implement unzip

---
 src/gleam/list.gleam | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'src')

diff --git a/src/gleam/list.gleam b/src/gleam/list.gleam
index 06e5a33..c82db2e 100644
--- a/src/gleam/list.gleam
+++ b/src/gleam/list.gleam
@@ -623,6 +623,17 @@ pub fn strict_zip(
   }
 }
 
+fn do_unzip(input, xs, ys) {
+  case input {
+    [] -> tuple(reverse(xs), reverse(ys))
+    [tuple(x, y), ..rest] -> do_unzip(rest, [x, ..xs], [y, ..ys])
+  }
+}
+
+pub fn unzip(input: List(tuple(a, b))) -> tuple(List(a), List(b)) {
+  do_unzip(input, [], [])
+}
+
 /// Insert a given value between each existing element in a given list.
 ///
 /// This function runs in linear time and copies the list.
-- 
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