1 files changed, 45 insertions, 0 deletions
diff --git a/include/mbgl/style/expression/step.hpp b/include/mbgl/style/expression/step.hpp
new file mode 100644
index 0000000000..e3c49bc609
--- /dev/null
+++ b/include/mbgl/style/expression/step.hpp
@@ -0,0 +1,45 @@
+
+#pragma once
+
+#include <mbgl/style/expression/expression.hpp>
+#include <mbgl/style/expression/parsing_context.hpp>
+#include <mbgl/style/conversion.hpp>
+
+#include <mbgl/util/range.hpp>
+
+#include <memory>
+#include <map>
+
+
+namespace mbgl {
+namespace style {
+namespace expression {
+
+class Step : public Expression {
+public:
+    Step(const type::Type& type_,
+          std::unique_ptr<Expression> input_,
+          std::map<double, std::unique_ptr<Expression>> stops_
+    ) : Expression(type_),
+        input(std::move(input_)),
+        stops(std::move(stops_))
+    {}
+
+    EvaluationResult evaluate(const EvaluationContext& params) const override;
+    void eachChild(const std::function<void(const Expression&)>& visit) const override;
+
+    const std::unique_ptr<Expression>& getInput() const { return input; }
+    Range<float> getCoveringStops(const double lower, const double upper) const;
+
+    bool operator==(const Expression& e) const override;
+
+    static ParseResult parse(const mbgl::style::conversion::Convertible& value, ParsingContext& ctx);
+
+private:
+    const std::unique_ptr<Expression> input;
+    const std::map<double, std::unique_ptr<Expression>> stops;
+};
+
+} // namespace expression
+} // namespace style
+} // namespace mbgl