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#pragma once
#include <mbgl/util/variant.hpp>
#include <mbgl/style/function.hpp>
namespace mbgl {
namespace style {
class Undefined {};
inline bool operator==(const Undefined&, const Undefined&) { return true; }
inline bool operator!=(const Undefined&, const Undefined&) { return false; }
template <class T>
class PropertyValue {
private:
using Value = variant<Undefined, T, Function<T>>;
Value value;
friend bool operator==(const PropertyValue& lhs, const PropertyValue& rhs) {
return lhs.value == rhs.value;
}
friend bool operator!=(const PropertyValue& lhs, const PropertyValue& rhs) {
return !(lhs == rhs);
}
public:
PropertyValue() : value() {}
PropertyValue( T constant) : value(constant) {}
PropertyValue(Function<T> function) : value(function) {}
bool isUndefined() const { return value.which() == 0; }
bool isConstant() const { return value.which() == 1; }
bool isFunction() const { return value.which() == 2; }
const T & asConstant() const { return value.template get< T >(); }
const Function<T>& asFunction() const { return value.template get<Function<T>>(); }
explicit operator bool() const { return !isUndefined(); };
template <typename Evaluator>
auto evaluate(const Evaluator& evaluator) const {
return Value::visit(value, evaluator);
}
};
} // namespace style
} // namespace mbgl
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