sakex

struct Point {
    x: f64,
    y: f64,
    z: f64,
}

impl Point {
    pub fn mid_point(&self, other: &Point) -> Point {
        Point {
            x: (self.x + other.x) / 2.0,

sakex

// AbstractButton.hpp (in GUI library)

#ifndef MEDIUM_ABSTRACT_BUTTON_H
#define MEDIUM_ABSTRACT_BUTTON_H

#include <string>

class AbstractButton {
    virtual void click() = 0;
    virtual std::string innerText() = 0;

sakex

// CounterButton.hpp
#ifndef MEDIUM_COUNTERBUTTON_HPP
#define MEDIUM_COUNTERBUTTON_HPP

#include <GUI/AbstractButton.hpp>

class CounterButton: public AbstractButton {
public:
    CounterButton(): count(0) {
    }

sakex

// main.cpp
#include <GUI/engine.hpp>
#include "CounterButton.hpp"
int main() {
    // Instantiate the hypothetical engine
    Engine engine(); 
    // Instantiate the button
    auto * counter = new CounterButton();
    // Adds button to the view
    engine.addButton(counter);

sakex

pub trait Button {
    fn click(&mut self);
    fn inner_text(&mut self) -> String;
}

pub struct CounterButton {
    count: i32
}

impl Button for CounterButton {

sakex

// src/main.rs
mod button;
mod engine;
mod bindings;

use button::Button;

pub struct CounterButton {
    count: i32
}

sakex

// src/engine.rs
use std::ffi::c_void;
use std::os::raw::c_char;
use crate::bindings::{engine_factory, register_button, AbstractButtonBinding};
use crate::Button;

pub struct Engine {
    ptr: *mut c_void
}

sakex

// src/bindings.rs
#[link(name = "gui", kind = "static")]
extern "C" {
    pub fn register_button(engine: *mut c_void, button: *mut c_void);
}

sakex

// bindings.hpp
extern "C" {
GUI::Engine *engine_factory() {
    return new GUI::Engine();
}
}

sakex

// src/bindings.rs
use std::ffi::c_void;
#[link(name = "gui", kind = "static")]
extern "C" {
/// Return a void pointer from the heap, the alternative would have been to write recursively
/// all the fields in a #[repr(C)] struct Engine ...
pub fn engine_factory() -> *mut c_void;
}