/*
 *  call-seq:
 *    Enumerable::Enumerator.new(obj, method = :each, *args)
 *
 *  Creates a new Enumerable::Enumerator object, which is to be
 *  used as an Enumerable object using the given object's given
 *  method with the given arguments.
 *
 *  e.g.:
 *      str = "xyz"
 *
 *      enum = Enumerable::Enumerator.new(str, :each_byte)
 *      a = enum.map {|b| '%02x' % b } #=> ["78", "79", "7a"]
 *
 */
static VALUE
enumerator_initialize(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    VALUE enum_obj, enum_method, enum_args;

    rb_scan_args(argc, argv, "11*", &enum_obj, &enum_method, &enum_args);

    if (enum_method == Qnil)
        enum_method = sym_each;

    rb_ivar_set(obj, id_enum_obj, enum_obj);
    rb_ivar_set(obj, id_enum_method, enum_method);
    rb_ivar_set(obj, id_enum_args, enum_args);

    return Qnil;
}

/*
 *  call-seq:
 *    enum.each {...}
 *
 *  Iterates the given block using the object and the method specified
 *  in the first place.
 *
 */
static VALUE
enumerator_each(obj)
    VALUE obj;
{
    VALUE val;

    obj = (VALUE)rb_node_newnode(NODE_MEMO,
                                 rb_ivar_get(obj, id_enum_obj),
                                 rb_to_id(rb_ivar_get(obj, id_enum_method)),
                                 rb_ivar_get(obj, id_enum_args));
    val = rb_iterate((VALUE (*)_((VALUE)))enumerator_iter, obj, rb_yield, 0);
    return val;
}