Working with native types

Accessing C++ types

C++ types are available within the cpp namespace, but you must replace :: with .. For example, std::string becomes cpp/std.string. This also works for type aliases. Given a type, a value can be constructed by calling the type. This supports both constructor overload resolution and aggregate initialization. C++ initializer lists are not currently supported.

(let [i (cpp/int)] ; Stack-allocates an int.
  )

Complex literal types

For complex types like template instantiations, pointers to members, and so on, jank supports a C++ domain-specific language (DSL). This is available implicitly when in type position, but it can be explicitly requested by using the special #cpp tag. The documentation for this DSL is here.

(let [i (#cpp (:* void))] ; Stack-allocates a void*.
  )

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 soon.

(cpp/raw "struct person
          {
            std::string name;
          };")