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#include <mruby.h>
#include <stdio.h>
// defining the function to be later bound to a ruby method
static mrb_value
multiply_numbers(mrb_state *mrb, mrb_value self)
{
// the number of keyword arguments we expect
uint32_t kw_num = 2;
const mrb_sym kw_names[] = { // the array where we specify what we expect the keyword arguments to be named
mrb_intern_lit(mrb, "x"), // we will expect an 'x' keyword
mrb_intern_lit(mrb, "y"), // we will expect a 'y' keyword
};
// initialize the array where the values of they kwargs will be temporarily stored
mrb_value kw_values[kw_num];
// When getting arguments, the function expects all the data we
// created above to be formatted into a specific struct. So we
// create this struct here.
const mrb_kwargs kwargs = {
kw_num, // number of kwargs
0, // number of required kwargs
kw_names, // names of kwargs
kw_values, // values of kwargs(will be filled out)
NULL // remaining kwargs(NULL specifies to error if other kwargs or args are given)
};
mrb_get_args(mrb, "|:", &kwargs); // get the arguments
if (mrb_undef_p(kw_values[0])){ // check if we actually recieved the first kwarg
kw_values[0] = mrb_fixnum_value(5); // set a default value if we didnt
// notice that because kw_values only holds ruby objects
// we must convert the number "5" into a ruby object by
// using the 'mrb_fixnum_value' function
}
if (mrb_undef_p(kw_values[1])){ // ditto with second kwarg
kw_values[1] = mrb_fixnum_value(5);
}
// we convert the ruby objects back into C
// ints, mutiply them and then return the
// value as a ruby object
return mrb_fixnum_value(mrb_as_int(mrb,kw_values[0]) * mrb_as_int(mrb,kw_values[1]));
}
// gem initializer
void
mrb_keyword_arguments_example_gem_init(mrb_state* mrb) {
struct RClass *keyword_arguments_example_class = mrb_define_module(mrb, "KeywordArgumentsExample");
mrb_define_class_method(
mrb, // Mruby VM state
keyword_arguments_example_class, // Class we bind method to
"multiply_numbers", // Name of method
multiply_numbers, // Function we are binding as a method
MRB_ARGS_ANY() // How many arguments are optional/required
);
}
// gem finalizer
void
mrb_keyword_arguments_example_gem_final(mrb_state* mrb) {
}
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