add options.Max(), options.Min()

3 files changed, 93 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a201d67..da568b5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+# v1.1.0 (TBD)
+
+Changes:
+
+- Add `options.Max()` and `options.Min()`.
+
 # v1.0.0 (2025-02-12)
 
 Initial release. The Go version requirement is 1.24.0 because `type Option`
diff --git a/options/options.go b/options/options.go
index bfae710..110b212 100644
--- a/options/options.go
+++ b/options/options.go
@@ -8,7 +8,11 @@
 // that cannot be expressed as methods on the Option type itself.
 package options
 
-import . "github.com/majewsky/gg/option"
+import (
+	"cmp"
+
+	. "github.com/majewsky/gg/option"
+)
 
 // NOTE: Keep functions sorted by name.
 
@@ -37,3 +41,45 @@ func Map[T, U any](o Option[T], mapping func(T) U) Option[U] {
 		return None[U]()
 	}
 }
+
+// Max returns the largest of its input values, while disregarding None values.
+// If there are no Some values, None is returned.
+func Max[T cmp.Ordered](inputs ...Option[T]) Option[T] {
+	var (
+		result T
+		isSome = false
+	)
+	for _, i := range inputs {
+		value, ok := i.Unpack()
+		if ok && (!isSome || result < value) {
+			result = value
+			isSome = true
+		}
+	}
+	if isSome {
+		return Some(result)
+	} else {
+		return None[T]()
+	}
+}
+
+// Min returns the smallest of its input values, while disregarding None values.
+// If there are no Some values, None is returned.
+func Min[T cmp.Ordered](inputs ...Option[T]) Option[T] {
+	var (
+		result T
+		isSome = false
+	)
+	for _, i := range inputs {
+		value, ok := i.Unpack()
+		if ok && (!isSome || result > value) {
+			result = value
+			isSome = true
+		}
+	}
+	if isSome {
+		return Some(result)
+	} else {
+		return None[T]()
+	}
+}
diff --git a/options/options_test.go b/options/options_test.go
index caeb303..84a61da 100644
--- a/options/options_test.go
+++ b/options/options_test.go
@@ -29,3 +29,43 @@ func TestMap(t *testing.T) {
 	AssertEqual(t, Map(None[int](), strconv.Itoa), None[string]())
 	AssertEqual(t, Map(Some(42), strconv.Itoa), Some("42"))
 }
+
+func TestMax(t *testing.T) {
+	AssertEqual(t, Max[int](), None[int]())
+	AssertEqual(t, Max(None[int]()), None[int]())
+	AssertEqual(t, Max(None[int](), None[int]()), None[int]())
+
+	AssertEqual(t, Max(Some(5)), Some(5))
+	AssertEqual(t, Max(Some(5), None[int]()), Some(5))
+	AssertEqual(t, Max(None[int](), Some(5)), Some(5))
+
+	AssertEqual(t, Max(Some(5), Some(23)), Some(23))
+	AssertEqual(t, Max(None[int](), Some(5), Some(23)), Some(23))
+	AssertEqual(t, Max(Some(5), None[int](), Some(23)), Some(23))
+	AssertEqual(t, Max(Some(5), Some(23), None[int]()), Some(23))
+
+	AssertEqual(t, Max(Some(23), Some(5)), Some(23))
+	AssertEqual(t, Max(None[int](), Some(23), Some(5)), Some(23))
+	AssertEqual(t, Max(Some(23), None[int](), Some(5)), Some(23))
+	AssertEqual(t, Max(Some(23), Some(5), None[int]()), Some(23))
+}
+
+func TestMin(t *testing.T) {
+	AssertEqual(t, Min[int](), None[int]())
+	AssertEqual(t, Min(None[int]()), None[int]())
+	AssertEqual(t, Min(None[int](), None[int]()), None[int]())
+
+	AssertEqual(t, Min(Some(5)), Some(5))
+	AssertEqual(t, Min(Some(5), None[int]()), Some(5))
+	AssertEqual(t, Min(None[int](), Some(5)), Some(5))
+
+	AssertEqual(t, Min(Some(5), Some(23)), Some(5))
+	AssertEqual(t, Min(None[int](), Some(5), Some(23)), Some(5))
+	AssertEqual(t, Min(Some(5), None[int](), Some(23)), Some(5))
+	AssertEqual(t, Min(Some(5), Some(23), None[int]()), Some(5))
+
+	AssertEqual(t, Min(Some(23), Some(5)), Some(5))
+	AssertEqual(t, Min(None[int](), Some(23), Some(5)), Some(5))
+	AssertEqual(t, Min(Some(23), None[int](), Some(5)), Some(5))
+	AssertEqual(t, Min(Some(23), Some(5), None[int]()), Some(5))
+}