!759

static class PerUser {
  S dialogID;
  S name;
}

static new Map<S, PerUser> perUserMap; // key = dialogID
static new ThreadLocal<PerUser> puCurrent;

p {
  load("perUserMap");
  makeBot("User Name Bot");
}

synchronized answer {
  if (!attn ()) null;
  
  // init per-user stuff
  
  S dialogID = getDialogID();
  if (dialogID == null) ret null; // need a dialog id to proceed
  PerUser pu = perUserMap.get(dialogID);
  if (pu == null) {
    pu = new PerUser;
    pu.dialogID = dialogID;
    printFormat("Created new dialog: *", dialogID);
    perUserMap.put(dialogID, pu);
  }
  puCurrent.set(pu);
  
  if (matchStart("my name is", s, m) || matchStart("i am", s, m) || matchStart("you can call me", s, m) || matchStart("call me", s, m) || matchStart("they call me", s, m) || matchStart("my friends call me", s, m)) {
    pu.name = unquote(m.rest().trim());
    save("perUserMap");
    ret "Hello " + pu.name + "!";
  }
  
  if (match("who am i?", s) || match("eleu what's my name", s)) {
    if (nempty(pu.name))
      ret "You are " + pu.name + ".";
    ret "I don't know, stranger. Who are you?";
  }
}

static synchronized S getUserName() {
  PerUser pu = perUserMap.get(getDialogID());
  ret pu == null ? null : pu.name;
}

Began life as a copy of #1002211