Using the new higher-kinded collection magic in ScalaQuery

gistfile1.scala

// A simple table with keys and values
val T = new Table[(Int, String)]("T") {
  def k = column[Int]("KEY", O.PrimaryKey)
  def v = column[String]("VALUE")
  def * = k ~ v
}

// Create the table and insert some data
T.ddl.create
T.insertAll(1 -> "a", 2 -> "b", 3 -> "c", 4 -> "d", 5 -> "e")

// Define a QueryTemplate for reading all key/value pairs up to a given key.
val upTo = for {
  k <- Parameters[Int]
  t <- T if t.k <= k
  _ <- Query orderBy t.k
} yield t

// Print a list of k/v pairs up to 3 the way we had to do it in the dark
// ages before higher-kinds and collection builders, by using the special
// .list method whose only purpose is building Lists from query results
println(upTo.list(3))

// And here's the fancy new way with .to
println(upTo.to[List](3))

// It can build any kind of collection for which a CanBuildFrom object is
// defined. Let's try it with a Set, an IndexedSeq (which really builds a
// Vector as IndexedSeq's default implementation) and a mutable ArrayBuffer
println(upTo.to[Set](3))
println(upTo.to[IndexedSeq](3))
println(upTo.to[ArrayBuffer](3))

// Let's read all keys into a real unboxed Array[Int]
val allKeys = T.map(_.k)
println(allKeys.to[Array]())