Need help decoding iRule

It appears to be a rule designed to create a persistence record based on values from the URI.

I've added syntax formatting and comments to the code below, roughly explaining the logic.

when HTTP_REQUEST {
      Search the URI for a slash (skipping the first character) and record it's index value into the value second.  If it doesn't find another slash, the value of second will be -1
    set second [string first "/" [HTTP::uri] 1]
      Add 1 to second
    incr second
      This if is true unless the search above did not find another slash, at which point the iRule exists without setting a persistence record
    if { $second > 0 } {
          Repeat above looking for a third slash.
        set third [string first "/" [HTTP::uri] $second] 
          Again skips the creation of a persistence record unless a third slash was found
        if { $third >= 0 } { 
              Create a universal persistence record based on the URI, but only the portion before the third slash
            set uniqueuri [string range [HTTP::uri] 0 $third]
            persist uie $uniqueuri 28800 
        }
    }
}