Question

I’ve seen BASIC and Apache Camel DSLs in Scala, and they’re just fantastic. Any more examples of such DSLs?

Answer 1

You have a good source in the MEAP (Early Access) book

DSL in action from Debasish Ghosh (blog: “Ruminations of a programmer)

Testing frameworks like scalatest are classic examples of DSL:

  test("pop is invoked on an empty stack") {     
    val emptyStack = new Stack[String]
    evaluating { emptyStack.pop() } should produce [NoSuchElementException]
    emptyStack should be ('empty)
  }

There are many others DSL-based frameworks out there:

• specs: “Behaviour-Driven-Design framework”

• internal DSLs

• Squeryl: “A Scala ORM and DSL for talking with Databases with minimum verbosity and maximum type safety”

    def songCountByArtistId: Query[GroupWithMeasures[Long,Long]] =
      from(artists, songs)((a,s) =>
        where(a.id === s.artistId)
        groupBy(a.id)
        compute(count)
      )