static Map<S, WikiPage> indexedSimpleWikipedia_fast() {
  File f = unpackSimpleWikipedia();
  File cacheFile = getProgramFile(#1008009, "simplewiki-" + fileSize(f) + ".index.gz");
  if (fileSize(cacheFile) == 0)
    saveGZStructureToFile(cacheFile, indexedSimpleWikipedia());
  ret (Map) unstructureGZFile(cacheFile);
}