From 2c25bacd35149f2dae2b97ad6c078d1514241b0f Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Tue, 7 Feb 2017 09:32:20 -0800
Subject: [PATCH] Alias std::experimental::optional

---
 include/mapbox/geojsonvt/tile.hpp  | 10 +++++-----
 include/mapbox/geojsonvt/types.hpp |  7 +++++--
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/include/mapbox/geojsonvt/tile.hpp b/include/mapbox/geojsonvt/tile.hpp
index c94bb91..9acd3ff 100644
--- a/include/mapbox/geojsonvt/tile.hpp
+++ b/include/mapbox/geojsonvt/tile.hpp
@@ -95,23 +95,23 @@ class InternalTile {
         return true;
     }
 
-    void addFeature(const vt_point& point, const property_map& props, const std::experimental::optional<identifier>& id) {
+    void addFeature(const vt_point& point, const property_map& props, const optional<identifier>& id) {
         tile.features.push_back({ transform(point), props, id });
     }
 
-    void addFeature(const vt_line_string& line, const property_map& props, const std::experimental::optional<identifier>& id) {
+    void addFeature(const vt_line_string& line, const property_map& props, const optional<identifier>& id) {
         const auto new_line = transform(line);
         if (!new_line.empty())
             tile.features.push_back({ std::move(new_line), props, id });
     }
 
-    void addFeature(const vt_polygon& polygon, const property_map& props, const std::experimental::optional<identifier>& id) {
+    void addFeature(const vt_polygon& polygon, const property_map& props, const optional<identifier>& id) {
         const auto new_polygon = transform(polygon);
         if (!new_polygon.empty())
             tile.features.push_back({ std::move(new_polygon), props, id });
     }
 
-    void addFeature(const vt_geometry_collection& collection, const property_map& props, const std::experimental::optional<identifier>& id) {
+    void addFeature(const vt_geometry_collection& collection, const property_map& props, const optional<identifier>& id) {
         for (const auto& geom : collection) {
             vt_geometry::visit(geom, [&](const auto& g) {
                 // `this->` is a workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61636
@@ -121,7 +121,7 @@ class InternalTile {
     }
 
     template <class T>
-    void addFeature(const T& multi, const property_map& props, const std::experimental::optional<identifier>& id) {
+    void addFeature(const T& multi, const property_map& props, const optional<identifier>& id) {
         const auto new_multi = transform(multi);
 
         switch (new_multi.size()) {
diff --git a/include/mapbox/geojsonvt/types.hpp b/include/mapbox/geojsonvt/types.hpp
index fac89fb..b54357a 100644
--- a/include/mapbox/geojsonvt/types.hpp
+++ b/include/mapbox/geojsonvt/types.hpp
@@ -89,6 +89,9 @@ struct vt_geometry_collection : std::vector<vt_geometry> {};
 using property_map = mapbox::geometry::property_map;
 using identifier = mapbox::geometry::identifier;
 
+template <class T>
+using optional = std::experimental::optional<T>;
+
 template <class T>
 struct vt_geometry_type;
 
@@ -128,12 +131,12 @@ struct vt_geometry_type<geometry::geometry_collection<double>> {
 struct vt_feature {
     vt_geometry geometry;
     property_map properties;
-    std::experimental::optional<identifier> id;
+    optional<identifier> id;
 
     mapbox::geometry::box<double> bbox = { { 2, 1 }, { -1, 0 } };
     uint32_t num_points = 0;
 
-    vt_feature(const vt_geometry& geom, const property_map& props, const std::experimental::optional<identifier>& id_)
+    vt_feature(const vt_geometry& geom, const property_map& props, const optional<identifier>& id_)
         : geometry(geom), properties(props), id(id_) {
 
         mapbox::geometry::for_each_point(geom, [&](const vt_point& p) {