Add option.values (#203)

Author: sporto

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- The `option` module gains the `values` function.
 - The `result` module gains the `values` function.
 - All modules now use the new `#(a, b, ...)` tuple syntax.
 

src/gleam/option.gleam

@@ -1,3 +1,5 @@
+import gleam/list
+
 /// Option represents a value that may be present or not. Some means the value is
 /// present, None means the value is not.
 ///
@@ -180,3 +182,17 @@ pub fn or(first: Option(a), second: Option(a)) -> Option(a) {
     None -> second
   }
 }
+
+/// Given a list of options
+/// Return only the values inside Some
+///
+/// ## Examples
+///
+/// ```
+/// > values([Some(1), None, Some(3)])
+/// [1, 3]
+/// ```
+///
+pub fn values(options: List(Option(a))) -> List(a) {
+  list.filter_map(options, fn(op) { to_result(op, "") })
+}

test/gleam/option_test.gleam

@@ -100,3 +100,8 @@ pub fn or_option_test() {
   |> option.or(None)
   |> should.equal(None)
 }
+
+pub fn values_test() {
+  option.values([Some(1), None, Some(3)])
+  |> should.equal([1, 3])
+}