[core] Add feature state support to expression

2 files changed, 27 insertions, 0 deletions

diff --git a/src/mbgl/renderer/possibly_evaluated_property_value.hpp b/src/mbgl/renderer/possibly_evaluated_property_value.hpp
index 625235011c..2e47e6c854 100644
--- a/src/mbgl/renderer/possibly_evaluated_property_value.hpp
+++ b/src/mbgl/renderer/possibly_evaluated_property_value.hpp
@@ -49,6 +49,16 @@ public:
             }
         );
     }
+
+    template <class Feature>
+    T evaluate(const Feature& feature, float zoom, const FeatureState& featureState, T defaultValue) const {
+        return this->match(
+            [&] (const T& constant_) { return constant_; },
+            [&] (const style::PropertyExpression<T>& expression) {
+                return expression.evaluate(zoom, feature, featureState, defaultValue);
+            }
+        );
+    }
 };
 
 template <class T>
diff --git a/src/mbgl/style/properties.hpp b/src/mbgl/style/properties.hpp
index 9d66f850de..b07456a96d 100644
--- a/src/mbgl/style/properties.hpp
+++ b/src/mbgl/style/properties.hpp
@@ -180,11 +180,28 @@ public:
                 });
         }
 
+        template <class T>
+        static T evaluate(float z, const GeometryTileFeature& feature, const FeatureState& state,
+                          const PossiblyEvaluatedPropertyValue<T>& v, const T& defaultValue) {
+            return v.match(
+                [&] (const T& t) {
+                    return t;
+                },
+                [&] (const PropertyExpression<T>& t) {
+                    return t.evaluate(z, feature, state, defaultValue);
+                });
+        }
+
         template <class P>
         auto evaluate(float z, const GeometryTileFeature& feature) const {
             return evaluate(z, feature, this->template get<P>(), P::defaultValue());
         }
 
+        template <class P>
+        auto evaluate(float z, const GeometryTileFeature& feature, const FeatureState& state) const {
+            return evaluate(z, feature, state, this->template get<P>(), P::defaultValue());
+        }
+
         Evaluated evaluate(float z, const GeometryTileFeature& feature) const {
             return Evaluated {
                 evaluate<Ps>(z, feature)...