From c153d1ab16d19724e47cc5c160b60b45cda195d2 Mon Sep 17 00:00:00 2001
From: Doug Tykocki <tykockda@gmail.com>
Date: Thu, 28 Dec 2023 09:54:40 -0500
Subject: Add set difference function

---
 src/gleam/set.gleam | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'src')

diff --git a/src/gleam/set.gleam b/src/gleam/set.gleam
index 9ffaccd..406d501 100644
--- a/src/gleam/set.gleam
+++ b/src/gleam/set.gleam
@@ -260,3 +260,20 @@ pub fn intersection(
   let #(larger, smaller) = order(first, second)
   take(from: larger, keeping: to_list(smaller))
 }
+
+/// Creates a new set that contains members that are present in the first set
+/// but not the second.
+///
+/// ## Examples
+///
+/// ```gleam
+/// > difference(from_list([1, 2]), from_list([2, 3, 4])) |> to_list
+/// [1]
+/// ```
+///
+pub fn difference(
+  from first: Set(member),
+  minus second: Set(member),
+) -> Set(member) {
+  drop(from: first, drop: to_list(second))
+}
-- 
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