Add int.clamp and float.clamp

5 files changed, 61 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1bc6cc4..0d6e5b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## Unreleased
+
+- The `int` module gains the `clamp` function.
+- The `float` module gains the `clamp` function.
+
 ## v0.13.0 - 2021-01-13
 
 - The `int` module gains the `absolute_value`, `sum` and `product` functions.
diff --git a/src/gleam/float.gleam b/src/gleam/float.gleam
index f3944f3..a672eca 100644
--- a/src/gleam/float.gleam
+++ b/src/gleam/float.gleam
@@ -29,6 +29,21 @@ pub fn to_string(f: Float) -> String {
   |> string_builder.to_string
 }
 
+/// Restrict a Float between a lower and upper bound
+///
+/// ## Examples
+///
+/// ```
+/// > clamp(1.2, min: 1.4, max: 1.6)
+/// 1.4
+/// ```
+///
+pub fn clamp(n: Float, min min_bound: Float, max max_bound: Float) -> Float {
+  n
+  |> min(max_bound)
+  |> max(min_bound)
+}
+
 /// Compares two floats, returning an order.
 ///
 /// ## Examples
diff --git a/src/gleam/int.gleam b/src/gleam/int.gleam
index a4a956a..96b4405 100644
--- a/src/gleam/int.gleam
+++ b/src/gleam/int.gleam
@@ -75,6 +75,21 @@ pub external fn to_base_string(Int, Int) -> String =
 pub external fn to_float(a: Int) -> Float =
   "erlang" "float"
 
+/// Restrict an Int between a lower and upper bound
+///
+/// ## Examples
+///
+/// ```
+/// > clamp(40, min: 50, max: 60)
+/// 50
+/// ```
+///
+pub fn clamp(n: Int, min min_bound: Int, max max_bound: Int) -> Int {
+  n
+  |> min(max_bound)
+  |> max(min_bound)
+}
+
 /// Compares two ints, returning an order.
 ///
 /// ## Examples
diff --git a/test/gleam/float_test.gleam b/test/gleam/float_test.gleam
index 2b3334e..3e0e6f6 100644
--- a/test/gleam/float_test.gleam
+++ b/test/gleam/float_test.gleam
@@ -38,6 +38,17 @@ pub fn to_string_test() {
   |> should.equal("-8.1")
 }
 
+pub fn clamp_test() {
+  float.clamp(1.4, min: 1.3, max: 1.5)
+  |> should.equal(1.4)
+
+  float.clamp(1.2, min: 1.3, max: 1.5)
+  |> should.equal(1.3)
+
+  float.clamp(1.6, min: 1.3, max: 1.5)
+  |> should.equal(1.5)
+}
+
 pub fn compare_test() {
   float.compare(0., 0.)
   |> should.equal(order.Eq)
diff --git a/test/gleam/int_test.gleam b/test/gleam/int_test.gleam
index 11906db..bec9624 100644
--- a/test/gleam/int_test.gleam
+++ b/test/gleam/int_test.gleam
@@ -12,6 +12,21 @@ pub fn absolute_value_test() {
   |> should.equal(123)
 }
 
+pub fn clamp_test() {
+  int.clamp(40, min: 30, max: 50)
+  |> should.equal(40)
+
+  int.clamp(20, min: 30, max: 50)
+  |> should.equal(30)
+
+  int.clamp(60, min: 30, max: 50)
+  |> should.equal(50)
+
+  // If the bounds are reversed we return the min
+  int.clamp(100, min: 50, max: 30)
+  |> should.equal(50)
+}
+
 pub fn to_string_test() {
   123
   |> int.to_string