A transpiler/module system polyfill for C++.
C++ does not have a real module system. One is in the works but in the
meanwhile, here is a future-compatible polyfill. Inspired by
this,
this, clang's
experimental module implementation
and the node.js module system.
Experimental. A work in progress.
A modue is a discrete unit of code, encapsulated in a file. It exposes at least one public value, function, class, etc. Let's use the following file strcture as an example...
index.cc
pizza.cc
cheese.cc
cc_modules/
serve/
index.cc
index.cc is the typical entry point for most programs.
//
// import the file "pizza.cc" as "pizza".
//
import pizza "./pizza.cc";
//
// import the module "serve" as "serve".
//
import serve "serve";
int main() {
serve.plate(pizza.make());
}To understand how the math module is imported, read
this.
The module imported by the code in index.cc.
#include <iostream>
#include <math.h>
//
// GLOBAL SCOPE
//
// Anything outside of export will be global, this will be
// accessible from ANY file. you should not put anything here
// unless you REALLY MEAN TO.
//
export {
//
// MODULE SCOPE
//
// Variables defined here are implicitly private, they are
// not exported, this applies to varibles imported from other
// modules.
//
const double pi = M_PI;
//
// import the file "./cheese.cc" as "chz"
//
import chz "./cheese.cc";
//
// Variables found after the "public:" label are exported!
//
public:
int make(int qty) {
return qty * pi + chz.add(secret_sauce);
}
//
// You can switch back and forth between public and private
// by using the "private:" label.
//
private:
int secret_sauce = 42;
}This file happens to be included by pizza.cc.
export {
public:
int add(int i) {
return i*i;
}
}export {
public:
void plate(int pizza) {
cout << pizza << endl;
}
}bale ./test/input/index.cc