build menu list of avatars on region

integer iMax;
integer iHandle;
integer iChannel;

key kToucher;
key kChosenUUID;
list lNames;
list lUUIDs;
list lTemp;
list lDialogLabels;
list lMenuChoices;

list lMenuButtons( integer vIntPag )
{
    integer vIdxBeg = 10 * (~-vIntPag);          //-- 10 * (vIntPag - 1), enclose "~-X" in parens to avoid LSL bug
    integer vIdxMax = -~(~([] != lMenuChoices) / 10); //-- (llGetListLength( lMenuChoices ) - 1) / 10 + 1
    list vLstRtn =
      llListInsertList(
        llList2List( lMenuChoices, vIdxBeg, vIdxBeg + 9 ), //-- grab 10 dialog buttons
        (list)("  <<---(" + (string)(vIntPag + (-(vIntPag > 1) | vIdxMax - vIntPag)) + ")"), //-- back button
        -1 ) + //-- inserts back button at index 9, pushing the last menu item to index 10
      (list)("  (" + (string)(-~((vIntPag < vIdxMax) * vIntPag)) + ")--->>"); //-- add fwd button at index 11

    return //-- fix the order to L2R/T2B
      llList2List( vLstRtn, -3, -1 ) + llList2List( vLstRtn, -6, -4 ) +
      llList2List( vLstRtn, -9, -7 ) + llList2List( vLstRtn, -12, -10 );
}

string strCaption = "Please choose someone:";
string strChoice;
default {
  state_entry() {
    iChannel = -((integer)(10000 + llFrand(9999999)));
  }

  attach(key id) {
    if(id){
      llRequestPermissions(id, PERMISSION_TAKE_CONTROLS);//needed to run in no script areas
    }
  }

  run_time_permissions(integer perm) {
    if(perm & PERMISSION_TAKE_CONTROLS){
      llTakeControls(CONTROL_ML_LBUTTON, FALSE, TRUE);
    }
  }

  touch_end(integer num_detected) {

    kToucher = llDetectedKey(0);
    lTemp = llGetAgentList(AGENT_LIST_REGION, []);//build list of avatars on the region

    lNames =[];//clear the lists of existing contents
    lUUIDs= [];
    lDialogLabels=[];
    lMenuChoices=[];

    iMax = -llGetListLength(lTemp);
    do{ //loop through lTemp and populate the lists
      key k = llList2Key(lTemp,iMax);
      lNames +=[llGetDisplayName(k)];
      lUUIDs +=[k];
    }
    while(++iMax);

    integer counter = 0 ;
    iMax = llGetListLength(lNames);
    do{
        lDialogLabels += [(string)(counter + 1)+": "+llList2String(lNames, counter)+"\n"];
        lMenuChoices +=[(string)(counter + 1)];
    }
    while(++counter < iMax);
    llOwnerSay("lMenuChoices is "+llList2CSV(lMenuChoices));

    llListenRemove(iHandle); // close
    iHandle = llListen(iChannel, "", "", "");

      string str = "";
      integer i;
      //Display the first 10 sites in dialog
      for (i=0;i<10;++i)
      {
          str += llList2String(lDialogLabels,i);
      }

      llDialog(kToucher, strCaption+"\n"+str, lMenuButtons(1), iChannel);

  }

  listen(integer channel, string name, key id, string message) {

    if(!llSubStringIndex(message, "  ")){//if the first two characters of the message are leading spaces, then it's the forward or back button
      string str  = "";
      integer menu =  (integer)llGetSubString( message, -~llSubStringIndex( message, "(" ), -1 );
      integer i;
      for (i=(10*(menu - 1));i<(10*menu);++i){
          str += llList2String(lDialogLabels,i);
      }
      llDialog(kToucher, strCaption+"\n"+str, lMenuButtons(menu), iChannel);
    }
    else{
        integer n = (integer)message -1;
        llRegionSayTo(kToucher, 0, "You chose: " + strChoice = llList2String(lNames,n)+", uuid "+(string)(kChosenUUID = llList2Key(lUUIDs, n)));
    }
  }
}