Psych::Emitter#alias

static VALUE alias(VALUE self, VALUE anchor)
{
    yaml_emitter_t * emitter;
    yaml_event_t event;
    TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

    if(!NIL_P(anchor)) {
        Check_Type(anchor, T_STRING);
        anchor = rb_str_export_to_enc(anchor, rb_utf8_encoding());
    }

    yaml_alias_event_initialize(
            &event,
            (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor))
            );

    emit(emitter, &event);

    return self;
}