4. Supported types #
4.1. List of supported types and conversion #
This is a list of supported types and how they are converted between C++ and Wren. Not everything can be mapped exactly (for example, integers are casted into doubles), so there are some compromises.
| C++ type | Wren type | Return value from Any |
|---|---|---|
| signed char (int8_t) | number (64-bit float) | .as<int8_t>() |
| unsigned char (uint8_t) | number (64-bit float) | .as<uint8_t>() |
| signed short (int16_t) | number (64-bit float) | .as<int16_t>() |
| unsigned short (uint16_t) | number (64-bit float) | .as<uint16_t>() |
| signed int (int32_t) | number (64-bit float) | .as<int32_t>() |
| unsigned int (uint32_t) | number (64-bit float) | .as<uint32_t>() |
| signed long long (int64_t) | number (64-bit float) | .as<int64_t>() |
| unsigned long long (uint64_t) | number (64-bit float) | .as<uint64_t>() |
| float | number (64-bit float) | .as<float>() |
| double | number (64-bit float) | .as<double>() |
| char | number (64-bit float) | .as<char>() |
| char[N] | string | Not possible to get raw char array from Wren, use std::string |
| char* | string | Not possible to get raw char pointer from Wren, use std::string |
| std::string | string | .as<std::string>() |
| std::shared_ptr<T> | T or null | .as<T>() or .as<T*>() or .shared<T>() |
| T (custom types) | foregin class of T | .as<T>() (if copy is supported) or .as<T*>() or .as<T&>() or .shared<T>() |
4.2. Unsupported types #
| C++ type | Reason |
|---|---|
| std::unique_ptr<T> | How would it work if you want to get std::unique_ptr<T>& ? Not possible to implement. |
| std::queue<T> | Can’t iterate over the elements without modifying the queue itself. |
4.3. STL Containers #
The following std containers are supported and will be converted to a Wren type. Read the 11. STL containers section to understand more about STL containers and how to use them.
Warning
By default the following STL containers below will be converted to a native type. If you add/bind any of these containers (except optional or variant) as a foregin class via
vm.module(...).klass<std::vector<int>>("VectorInt")then that type will no longer be treated as a native type. Only the type you have registered, for examplestd::vector<int>will be treated as such, other types of the same container, for examplestd::vector<float>will still be treated as a native list.Whether the STD container is converted a Wren native list/map or into a Wren foreign class is checked at runtime.
Read the 11. STL containers section to understand how it works.
| C++ type | Wren type | Return value from Any |
|---|---|---|
| std::variant<A, B, C> | A or B or C | .as<A or B or C>() or .as<std::variant<A, B, C>>() |
| std::optional<T> | T or null | .as<T>() (only if not null) or .as<std::optional<T>>() |
| std::vector<T> | native list of T | .as<std::vector<T>>() |
| std::list<T> | native list of T | .as<std::list<T>>() |
| std::deque<T> | native list of T | .as<std::deque<T>>() |
| std::set<T> | native list of T | .as<std::set<T>>() |
| std::unordered_set<T> | native list of T | .as<std::unordered_set<T>>() |
| std::map<std::string, T> | native map of T | .as<std::map<std::string, T>>() |
| std::unordered_map <std::string, T> | native map of T | .as<std::unordered_map <std::string, T>>() |