Working with native types

Accessing C++ types

C++ types are available under the cpp/ namespace, if you replace :: with .. For example, std::string becomes cpp/std.string. This also works for type aliases.

Complex literal types

If your C++ type is not representable using jank’s interop syntax, due to template arguments or other shenanigans, you can use cpp/type to provide the complete type using an inline C++ string. For example, here’s how we both grab the type and construct it (call the type), to get a value. In this example, we build a C++ ordered map from std::string to pointers to functions which take in an int and return an int.

(let [m ((cpp/type "std::map<std::string, int (*)(int)>"))]
  )

Defining new types

There isn’t yet a way to define new types using jank’s syntax, but you can always drop to cpp/raw to either include headers or define some C++ types inline. Improved support for extending jank’s object model with JIT (just in time) compiled types will be coming in 2026.