gistfile1.scala

// I think this is possible, if we just ignore the names.
//
// year = :year, month = :month, day = :day
get("/date/:year/:month/:day") { (year, month, day) =>
    <ul>
      <li>Year: { year }</li>
      <li>Month: { month }</li>
      <li>Day: { day }</li>
    </ul>
}

// But if we ignore the names, bad things happen:
//
// year = :monht, month = :day, day = :year
get("/date/:month/:day/:year") { (year, month, day) =>
    <ul>
      <li>Year: { year }</li>
      <li>Month: { month }</li>
      <li>Day: { day }</li>
    </ul>
}

// Something like this might be able to put the parameters, 
// in any order, but it's not nearly as nice as what you proposed.
// 
// year = :1, month = :2, day = :3
get("/date/:2/:3/:1") { (year, month, day) =>
    <ul>
      <li>Year: { year }</li>
      <li>Month: { month }</li>
      <li>Day: { day }</li>
    </ul>
}

// Or, if it's just based on convention...
// 
// year = first :?, month = second :?, day = third :?
get("/date/:?/:?/:?") { (year, month, day) =>
    <ul>
      <li>Year: { year }</li>
      <li>Month: { month }</li>
      <li>Day: { day }</li>
    </ul>
}

Perfect!
:? Does not blur the closure parameter names with request path parameters.
Of course, this way one cannot use params("?") at the same time of passing params to the closure. Nice.
Hope the idea to be useful.

Yes, this is definitely a feature that we would like to add. Thanks for the idea!