I need to be able to load files into a string a compile time with C++?

Question

I need a portable cross-platform way to load text files at compile time. My application is a virtual machine for a domain specific language that I have written so I need the core class files to be embedded. They should not be loaded at runtime. Is this possible with C/C++ without the need of a third party library or tool.

Assume some main.cpp file as follows.

// load some core script
static constexpr std::string coreScript = LOAD_FILE("/path/to/lib/com/example/Person.mylang");

// main()
int main()
{
    // some setup function that returns an instance of the FFI
    MyLangEnv *env = mlvm_setup(); // some setup function that returns an instance of the FFI

    // register native Person type
    env->native()->type("com/example/Person", &Person::construct)
    ->property("firstName", &Person::firstName)
    ->property("lastName", &Person::lastName)
    ->property("age", &Person::age)
    ->method("speak", &Person::speak);
    ;

    // run script so that the class is exposed to runtime
    env->run()->mylangScript(coreScript);

    // now person can be instantiated
    Person *person = env->make()->object("com/example/Person", "Jane", "Doe", 22);
    assert(person);

    // set global
    env->set()->global("person", person);

    // eval
    env->eval("print(person.firstName)"); // outputs "Jane"

    // call speak()
    env->call()->property(person, "speak");


    // run gc() and destroy environment
    env->kill();
    return 0;
}

I would like the script to work in this way. Is this possible in C++ in a way that also will work with Objective-C++?

Answer 1

I followed the advise of @TedLyngmo to solve this problem.

I ended up writing a Python script that traversed a directory to load all of the source files of my language and generated a large C++ file containing all of the data needed to use within the virtual machine at runtime. I found resources online to help me with the API and I had some familiarity with Python. I used the os module to get all files in a directory and the string method endswith to test if a file had the correct extension. Finally I generated the new file via open('path/to/generated.cpp', 'w+') if the file did not exist and open('path/to/generated.cpp', 'w') if it did exist.

I have not figured out how to get Xcode to run python script at build time but I did get it to run a bash. I'll have to make adjustments later. For now this works fine.