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Diffstat (limited to 'include/mbgl/style/expression/coercion.hpp')
-rw-r--r-- | include/mbgl/style/expression/coercion.hpp | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/include/mbgl/style/expression/coercion.hpp b/include/mbgl/style/expression/coercion.hpp new file mode 100644 index 0000000000..665bb7ce7c --- /dev/null +++ b/include/mbgl/style/expression/coercion.hpp @@ -0,0 +1,34 @@ +#pragma once +#include <mbgl/style/expression/expression.hpp> +#include <mbgl/style/conversion.hpp> +#include <memory> +#include <vector> + +namespace mbgl { +namespace style { +namespace expression { + +/** + * Special form for error-coalescing coercion expressions "to-number", + * "to-color". Since these coercions can fail at runtime, they accept multiple + * arguments, only evaluating one at a time until one succeeds. + */ +class Coercion : public Expression { +public: + Coercion(type::Type type_, std::vector<std::unique_ptr<Expression>> inputs_); + + 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; +private: + EvaluationResult (*coerceSingleValue) (const Value& v); + std::vector<std::unique_ptr<Expression>> inputs; +}; + +} // namespace expression +} // namespace style +} // namespace mbgl + |