From 141e995806576364d185626176c1b993fc519291 Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Fri, 28 Oct 2016 16:39:50 -0700
Subject: [core] Add support for data-driven styling

---
 include/mbgl/util/feature.hpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'include/mbgl/util/feature.hpp')

diff --git a/include/mbgl/util/feature.hpp b/include/mbgl/util/feature.hpp
index b72aa15ddd..4eeceda944 100644
--- a/include/mbgl/util/feature.hpp
+++ b/include/mbgl/util/feature.hpp
@@ -12,4 +12,21 @@ using PropertyMap = mapbox::geometry::property_map;
 using FeatureIdentifier = mapbox::geometry::identifier;
 using Feature = mapbox::geometry::feature<double>;
 
+template <class T>
+optional<T> numericValue(const Value& value) {
+    return value.match(
+        [] (uint64_t t) {
+            return optional<T>(t);
+        },
+        [] (int64_t t) {
+            return optional<T>(t);
+        },
+        [] (double t) {
+            return optional<T>(t);
+        },
+        [] (auto) {
+            return optional<T>();
+        });
+}
+
 } // namespace mbgl
-- 
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