Jule Manual

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Structures ​

Linking C Structures ​

As always, your links are reliable. Generics are supported in linking a structure. Not all fields have to be specified. If you're only going to use the struct by name, you can also declare it without the fields. The requirements here are limited to your needs and what needs to be declared for compliance.

For example:

jule
cpp struct my_struct{}
jule
cpp struct my_struct {
    x: int
    y: str
}

WARNING

  • Linked structure's fields are public by default all time. So if you want export your linked structure, use type alias. No worry, fields will be available. It is useful for write low-level APIs.
  • Your compiler will not automatically initialize with default value to fields that are not assigned in the struct literal for C++ linked structs.
  • If the linked structures have a constructor, the generated IR may have compilation errors.

C++ Structures and Typedef C Structures ​

Structure linking is C-compliant by default. You can use the typedef directive to make this compatible with C++ or typedef C structures. The typedef directive enables generating compatible code for C++ and typedef C structures in code generation.

For example:

jule
#typedef
cpp struct my_struct {
    x: int
    y: str
}

Linking Methods ​

Your C++ structures may have methods and you want to link them to Jule. To do this, struct fields might be a trick for you. You can define struct fields with the name of your methods in the function type.

For example:

Our mystruct.hpp file:

cpp
struct MyStruct {
    jule::Str text;

    void my_method(void) {
        std::cout << "My text is: " << text << std::endl;
    }
};

Our main.jule file:

jule
cpp use "mystruct.hpp"

#typedef
cpp struct MyStruct {
    text:      str
    my_method: fn()
}

fn main() {
    let ms = cpp.MyStruct{
        text: "Hello World",
    }
    ms.my_method()
}

If the struct is a typedef, say it's a typedef with attribute typedef for correct linking:

jule
#typedef
cpp struct my_struct {}

Classes ​

In C++, structs and classes are almost the same thing. A structure linking is typically class compatible. In other words, interoperability can also be used with classes struct linking.

For example:

The C++ class:

cpp
class MyClass {
public:
    jule::Str data;
    jule::Str magic_data;
};

The Jule code:

jule
#typedef
cpp struct MyClass {
    data: str
    magic_data: str
}