feat(float): add sum function

2 files changed, 27 insertions, 0 deletions

diff --git a/src/gleam/float.gleam b/src/gleam/float.gleam
index 24f0330..3d611b5 100644
--- a/src/gleam/float.gleam
+++ b/src/gleam/float.gleam
@@ -171,3 +171,22 @@ pub fn square_root(number: Float) -> Result(Float, Nil) {
 pub fn negate(x: Float) -> Float {
   -1. *. x
 }
+
+/// Sums a list of Floats.
+///
+/// ## Example
+///
+///    > sum([1.0, 2.2, 3.3])
+///    6.5
+///
+pub fn sum(numbers: List(Float)) -> Float {
+  numbers
+  |> do_sum(0.0)
+}
+
+fn do_sum(numbers: List(Float), initial: Float) -> Float {
+  case numbers {
+    [] -> initial
+    [x, ..rest] -> do_sum(rest, x +. initial)
+  }
+}
diff --git a/test/gleam/float_test.gleam b/test/gleam/float_test.gleam
index be1f22d..2ebaefc 100644
--- a/test/gleam/float_test.gleam
+++ b/test/gleam/float_test.gleam
@@ -242,3 +242,11 @@ pub fn negate_test() {
   float.negate(0.)
   |> should.equal(0.)
 }
+
+pub fn sum_test() {
+  float.sum([])
+  |> should.equal(0.0)
+
+  float.sum([1.0, 2.2, 3.3])
+  |> should.equal(6.5)
+}