set.delete!

3 files changed, 22 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 531cba6..9c80add 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,8 @@
 - Created the `iterator` module with the `unfold`, `repeatedly`, `repeat`,
   `from_list`, `fold`, `run`, `to_list`, `take`, `drop`, `map`, `filter`,
   `cycle`, and `range` functions.
-- Created the `set` module with the `new`, `insert`, and `contains` functions.
+- Created the `set` module with the `new`, `insert`, `delete`, and `contains`
+  functions.
 - Created the `io` module with the `print`, `println`, and `debug` functions.
 - Created the `queue` module with the `new`, `from_list`, `to_list`,
   `is_empty`, `length`, `push_back`, `push_front`, `pop_back`, `pop_front`,
diff --git a/src/gleam/set.gleam b/src/gleam/set.gleam
index cd7cbe0..7b52064 100644
--- a/src/gleam/set.gleam
+++ b/src/gleam/set.gleam
@@ -61,3 +61,15 @@ pub fn contains(in set: Set(element), this member: element) -> Bool {
   |> map.get(member)
   |> result.is_ok
 }
+
+/// Remove an element from a set. If the set does not contain the element then
+/// the set is returned unchanged.
+///
+/// ## Examples
+///
+///    > new() |> insert(2) |> delete(2) |> contains(1)
+///    False
+///
+pub fn delete(from set: Set(element), this member: element) -> Set(element) {
+  Set(map: map.delete(set.map, member))
+}
diff --git a/test/gleam/set_test.gleam b/test/gleam/set_test.gleam
index 7247c5c..dcc1356 100644
--- a/test/gleam/set_test.gleam
+++ b/test/gleam/set_test.gleam
@@ -30,3 +30,11 @@ pub fn contains_test() {
   |> set.contains(this: 1)
   |> should.be_false
 }
+
+pub fn delete_test() {
+  set.new()
+  |> set.insert(1)
+  |> set.delete(1)
+  |> set.contains(1)
+  |> should.be_false
+}