Add option.FromErr and option.Equal (#2186)

Author: eandre

pkg/option/option.go

@@ -77,6 +77,15 @@ func FromPointer[T any](v *T) Option[T] {
 	return Some[T](*v)
 }
 
+// FromErr returns an Option[string] where a nil error is considered None
+// and any other value is considered Some, with the error message as the value.
+func FromErr(err error) Option[string] {
+	if err == nil {
+		return None[string]()
+	}
+	return Some(err.Error())
+}
+
 // Some returns an Option with the given value and present set to true
 //
 // This means Some(nil) is a valid present Option

pkg/option/pkgfn.go

@@ -39,3 +39,14 @@ func FoldLeft[T, R any](option Option[T], zero R, f func(accum R, value T) R) R
 	}
 	return zero
 }
+
+// Equal returns true if both Options are equal.
+func Equal[T comparable](a, b Option[T]) bool {
+	if a.present != b.present {
+		return false
+	}
+	if !a.present {
+		return true
+	}
+	return a.value == b.value
+}