Relax type checking for "length"

1 files changed, 32 insertions, 0 deletions

diff --git a/include/mbgl/style/expression/length.hpp b/include/mbgl/style/expression/length.hpp
new file mode 100644
index 0000000000..1d754f1932
--- /dev/null
+++ b/include/mbgl/style/expression/length.hpp
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <mbgl/style/expression/expression.hpp>
+#include <mbgl/style/conversion.hpp>
+#include <mbgl/style/expression/parsing_context.hpp>
+
+#include <memory>
+#include <vector>
+
+namespace mbgl {
+namespace style {
+namespace expression {
+
+class Length : public Expression {
+public:
+    Length(std::unique_ptr<Expression> input);
+
+    static ParseResult parse(const mbgl::style::conversion::Convertible& value, ParsingContext& ctx);
+
+    EvaluationResult evaluate(const EvaluationContext& params) const override;
+    void eachChild(const std::function<void(const Expression&)>& visit) const override;
+    bool operator==(const Expression& e) const override;
+    std::vector<optional<Value>> possibleOutputs() const override;
+    std::string getOperator() const override { return "length"; }
+
+private:
+    std::unique_ptr<Expression> input;
+};
+
+} // namespace expression
+} // namespace style
+} // namespace mbgl