// a, b are indices into the chat history
static Web chatLinesAsWeb2(int a, int b, O makeNode) {
  ret chatLinesAsWeb2(stefansChat_readHistory_fullMsgs(a, b), makeNode);
}

// makeNode: voidfunc(ChatMsg, WebNode)
static Web chatLinesAsWeb2(L<ChatMsg> msgs, O makeNode) {
  Web web = simpleWeb();
  new L<WebNode> nodes;
  for i over msgs: {
    ChatMsg msg = msgs.get(i);
    WebNode n = web.newNode();
    web_addRelation(last(nodes), n, 'then);
    web_setPosition(n, 0.5, 0.2+i*0.6/max(1, l(msgs)-1));
    nodes.add(n);
    pcallF(makeNode, msg, n);
  }
  ret web;
}