Interesting DSLs, Implemented in Scala? [closed]
I've seen BASIC and Apache Camel DSLs in Scala, and they're just fantastic. Any more examples of such DSLs?
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) )
lift-json provides a DSL to generate JSON. For example the following DSL:
("person" ->
("name" -> "Joe") ~
("age" -> 35) ~
("spouse" ->
("person" ->
("name" -> "Marilyn") ~
("age" -> 33)
)
)
)
creates the following JSON:
{
"person": {
"name": "Joe",
"age": 35,
"spouse": {
"person": {
"name": "Marilyn",
"age": 33
}
}
}
}
ScalaModules is a DSL for working with OSGi.
Another one is available with Apache Camel a platform for enterprise integration.
Scala-Query and Squeryl also provide DSLs for querying databases among other things.
ScalaTest is also an awesome example of what is possible.
Two good examples are the built-in DSLs for Parser Combinators and Actors. There is a SQL wrapper called DBC (not yet ready), here you can see how it looks like: http://scala.sygneca.com/libs/dbc
XML in Scala is another example.
The ScalaQL paper (PDF) describes the implementation of an interesting DSL for language integrated database queries.
And then there's Foursquare's Rogue http://engineering.foursquare.com/2011/01/21/rogue-a-type-safe-scala-dsl-for-querying-mongodb/
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