1 files changed, 23 insertions, 1 deletions
diff --git a/src/mbgl/style/layout_property.hpp b/src/mbgl/style/layout_property.hpp
index 6ea06ce556..25cff4b92d 100644
--- a/src/mbgl/style/layout_property.hpp
+++ b/src/mbgl/style/layout_property.hpp
@@ -1,6 +1,9 @@
 #pragma once
 
+#include <mbgl/style/property_value.hpp>
+#include <mbgl/style/data_driven_property_value.hpp>
 #include <mbgl/style/property_evaluator.hpp>
+#include <mbgl/style/data_driven_property_evaluator.hpp>
 #include <mbgl/util/indexed_tuple.hpp>
 
 namespace mbgl {
@@ -11,9 +14,19 @@ class PropertyEvaluationParameters;
 template <class T>
 class LayoutProperty {
 public:
-    using EvaluatorType = PropertyEvaluator<T>;
     using UnevaluatedType = PropertyValue<T>;
+    using EvaluatorType = PropertyEvaluator<T>;
     using EvaluatedType = T;
+    using Type = T;
+};
+
+template <class T>
+class DataDrivenLayoutProperty {
+public:
+    using UnevaluatedType = DataDrivenPropertyValue<T>;
+    using EvaluatorType = DataDrivenPropertyEvaluator<T>;
+    using EvaluatedType = PossiblyEvaluatedPropertyValue<T>;
+    using Type = T;
 };
 
 template <class... Ps>
@@ -29,6 +42,15 @@ public:
     class Evaluated : public Tuple<EvaluatedTypes> {
     public:
         using Tuple<EvaluatedTypes>::Tuple;
+
+        template <class P>
+        typename P::Type evaluate(float z, const GeometryTileFeature& feature) const {
+            using T = typename P::Type;
+            return this->template get<P>().match(
+                [&] (const T& t) { return t; },
+                [&] (const SourceFunction<T>& t) { return t.evaluate(feature, P::defaultValue()); },
+                [&] (const CompositeFunction<T>& t) { return t.evaluate(z, feature, P::defaultValue()); });
+        }
     };
 
     class Unevaluated : public Tuple<UnevaluatedTypes> {