Enumerator::Chain#rewind

static VALUE
enum_chain_rewind(VALUE obj)
{
    struct enum_chain *objptr = enum_chain_ptr(obj);
    VALUE enums = objptr->enums;
    long i;

    for (i = objptr->pos; 0 <= i && i < RARRAY_LEN(enums); objptr->pos = --i) {
        rb_check_funcall(RARRAY_AREF(enums, i), id_rewind, 0, 0);
    }

    return obj;
}