srecord IndexedWikiPage(S title, long start, int len) {}

please include function iteratorFromFunction.
  
static IterableIterator<IndexedWikiPage> indexSimpleWikipedia() {
  File f = unpackSimpleWikipedia();
  final ByteCountingLineReader reader = new(bufferedFileInputStream(f, 1024*1024));
  
  ret main.<IndexedWikiPage> iteratorFromFunction(new O {
    int lines = 0, pages = 0;

    IndexedWikiPage get() ctex {
      long pageStart = 0;
      StringBuilder pageBuf = null;
      
      while licensed {
        long offset = reader.byteCount();
        S line = reader.readLine();
        if (line == null) break;
        line = trim(line);
        if (eq(line, "<page>")) {
          pageStart = offset;
          pageBuf = new StringBuilder;
        }
        if (pageBuf != null)
          pageBuf.append(line).append("\n");
        if (eq(line, "</page>")) {
          L<S> tok = htmlTok(str(pageBuf));
          S title = trim(htmldecode(join(contentsOfContainerTag(tok, "title"))));
          if ((++pages % 1000) == 0) {
            fractionDone(pages/228400.0);
            print("Pages: " + pages + " (" + title + ")");
            sleep(1);
          }
          ret new IndexedWikiPage(title, pageStart, toInt(reader.byteCount()-pageStart));
        }
      }
      fractionDone(1);
      reader.close();
      null;
    }
  });
}

Began life as a copy of #1008067