From 56ee329d79d076742e60c10974c471cc8119ed05 Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Thu, 3 Jan 2019 22:49:40 +1100
Subject: [PATCH] Add Optional::value_or_compute for lazy computation of
 default value

---
 src/optional.hh | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/optional.hh b/src/optional.hh
index dfa84694..aef1a751 100644
--- a/src/optional.hh
+++ b/src/optional.hh
@@ -84,6 +84,9 @@ public:
     template<typename U>
     T value_or(U&& fallback) const { return m_valid ? m_value : T{std::forward<U>(fallback)}; }
 
+    template<typename U>
+    T value_or_compute(U&& compute_func) const { return m_valid ? m_value : compute_func(); }
+
     void reset() { destruct_ifn(); m_valid = false; }
 
 private: