mruby proc call example

example.rb

class Bar
  def initialize(name)
    @name = name
    @x = 0
    @y = 0
  end

  def name
    @name
  end

  def x
    @x
  end

  def y
    @y
  end

  def move_bar
    @x += 10
    @y += 10
  end
    
  def execute_with(b)
    b.call(@x, @y)
  end
end

test.c

#include "mruby.h"
#include "mruby/proc.h"
#include "mruby/array.h"
#include "mruby/string.h"
#include "mruby/compile.h"
#include "mruby/dump.h"
#include <stdio.h>
#include <string.h>

static mrb_value bar_execute_with(mrb_state *mrb, mrb_value obj)
{
  fprintf(stderr, "Inside execute_with block\n");
  
  mrb_value x, y;
  mrb_get_args(mrb, "oo", &x, &y);
  
  fprintf(stderr, "Values: x=%d, y=%d\n", x.value.i, y.value.i);
  
  mrb_value count_value;
  count_value.tt = MRB_TT_FIXNUM;
  count_value.value.i = x.value.i + y.value.i;

  // If raise gets called here no segfault
  // mrb_raise(mrb, E_TYPE_ERROR, "Testing...");

  return mrb_Integer(mrb, count_value);
}

int main(int argc, char **argv)
{
  FILE *fp = fopen("example.mrb", "rb");

  mrb_state *mrb = mrb_open();
  int n = mrb_load_irep(mrb, fp);

  mrb_run(mrb, mrb_proc_new(mrb, mrb->irep[n]), mrb_top_self(mrb));

  mrb_value args[1];
  args[0] = mrb_str_new2(mrb, "Bar1");
  mrb_value barInstance = mrb_class_new_instance(mrb, 1, args, mrb_class_get(mrb, "Bar"));

  mrb_value bar_name = mrb_funcall_argv(mrb, barInstance, mrb_intern(mrb, "name"), 0, NULL);
  mrb_value bar_x = mrb_funcall_argv(mrb, barInstance, mrb_intern(mrb, "x"), 0, NULL); 
  mrb_value bar_y = mrb_funcall_argv(mrb, barInstance, mrb_intern(mrb, "y"), 0, NULL);
  
  fprintf(stderr, "Bar update location before => %s, %d, %d\n", mrb_str_ptr(bar_name)->ptr, bar_x.value.i, bar_x.value.i);
  
  mrb_funcall_argv(mrb, barInstance, mrb_intern(mrb, "move_bar"), 0, NULL);
  
  bar_x = mrb_funcall_argv(mrb, barInstance, mrb_intern(mrb, "x"), 0, NULL); 
  bar_y = mrb_funcall_argv(mrb, barInstance, mrb_intern(mrb, "y"), 0, NULL);
  
  fprintf(stderr, "Bar update location after => %s, %d, %d\n", mrb_str_ptr(bar_name)->ptr, bar_x.value.i, bar_x.value.i);

  struct RProc *b = mrb_proc_new_cfunc(mrb, bar_execute_with);
  mrb_value proc = mrb_obj_value(b);
    
  mrb_value ewret = mrb_funcall_argv(mrb, barInstance, mrb_intern(mrb, "execute_with"), 1, &proc);
  fprintf(stderr, "Output: %d\n", ewret.value.i);

  fclose(fp);
}