React differently if second time user visits domain

I am working on building a Kynetx app that fires a different action on a domain if it is the second time a user has visited the page. I think I need to use a persistant trail to mark when a user visits a page but I'm not sure how to check the trail to see if a value is already there and matches the current domai开发者_如何学编程n.

Current code:

rule put_data_onto_trail {
  select when pageview ".*"
  pre {
    domain = page:url("domain");
  }
  {
    notify("Thanks for visiting #{domain}","You visit has been recorded") with sticky = true;
  }
  fired {
    mark ent:visitedDomains with domain;
  }
}

KRL provides the seen operator just for this purpose. It takes a regular expression as a string. So your if check could look something like this:

if seen ".*awesome.*" in ent:mytrail then {
    // take over the world
}