How to load mruby code from external file in C program?

Question

I'm getting started with mruby. I'm also pretty new to programming in C, so I may not be familiar with many of the basics. I was able to compile the example mruby program which loads the ruby code from a string. Now I would like to load it from an external file. Here's the example code that I'm using:

#include <stdlib.h>
#include <stdio.h>
#include <mruby.h>

static mrb_value my_c_method(mrb_state *mrb, mrb_value value)
{
  puts("Called my C method");
  return value;
}

int main(void)
{
  mrb_state *mrb = mrb_open();

  struct RClass *mymodule = mrb_define_module(mrb, "MyModule");
  mrb_define_class_method(mrb, mymodule, "my_c_method", my_c_method, MRB_ARGS_NONE());

  mrb_load_string(mrb, "MyModule.my_c_method"); // move this to an external file
  return 0;
}

As you can see in the example above, I would like to move the ruby code to an external file. I'm a little confused as to whether or not I can simply "include" the ruby file, or if I need to precompile it into an .mrb file. Even then I'm not sure how to include that .mrb file when compiling.

What do I need to change to be able to load the ruby code from an external file?

Answer 1

In the mruby/compile.h there is a method called mrb_load_file which allows you to load a ruby file and execute it with mruby:

#include <stdlib.h>
#include <stdio.h>

#include <mruby.h>
#include <mruby/compile.h>

static mrb_value my_c_method(mrb_state *mrb, mrb_value value)
{
  puts("Called my C method");
  return value;
}

int main(void)
{
  mrb_state *mrb = mrb_open();

  struct RClass *mymodule = mrb_define_module(mrb, "MyModule");
  mrb_define_class_method(mrb, mymodule, "my_c_method", my_c_method, MRB_ARGS_NONE());

  FILE *f = fopen("example.rb", "r");
  mrb_load_file(mrb, f);

  return 0;
}