/*
 *  call-seq:
 *     fis.create_index(dir) -> self
 *     
 *  Create a new index in the directory specified. The directory +dir+ can
 *  either be a string path representing a directory on the file-system or an
 *  actual directory object. Care should be taken when using this method. Any
 *  existing index (or other files for that matter) will be deleted from the
 *  directory and overwritten by the new index.
 */
static VALUE
frt_fis_create_index(VALUE self, VALUE rdir)
{
    FieldInfos *fis = (FieldInfos *)DATA_PTR(self);
    Store *store = NULL;
    if (TYPE(rdir) == T_DATA) {
        store = DATA_PTR(rdir);
        REF(store);
    } else {
        StringValue(rdir);
        frt_create_dir(rdir);
        store = open_fs_store(rs2s(rdir));
    }
    index_create(store, fis);
    store_deref(store);
    return self;
}