Collection of Scala Macro goodies (BSD-licensed)

• Streams (MIGRATED TO ITS OWN REPO) provide a macro and a compiler plugin that optimize streamed collection operations / for comprehensions by rewriting them to equivalent while loops (Scala 2.11.x):

  for (i <- 0 to n;
       ii = i * i;
       j <- i to n;
       jj = j * j;
       if (ii - jj) % 2 == 0;
       k <- (i + j) to n)
    yield { (ii, jj, k) }

• Loops provide a macro that optimizes simple foreach loops on Ranges by rewriting them to equivalent while loops (Scala 2.10.x):

  import scalaxy.loops._
  
  for (i <- 0 until 100000000 optimized) { ... }

  (special case of / superseeded by Streams below)

• JSON (ScalaDoc) provides macro-based json string interpolation with smart error reporting, compile-time renormalization, deconstruction and more.

• Parano (MIGRATED TO ITS OWN REPO) provides compile-time checks to avoid common naming mistakes (ambiguous or swapped case class field extractor names, ambiguous unnamed param names with same type...)

• Privacy changes the default member visibily from public to private (unless the @public annotation is used)

• Beans (ScalaDoc) are a nifty combination of Dynamics and macros that provide a type-safe eye-candy syntax to set fields of regular Java Beans in a Scala way (without any runtime dependency at all!):

  import scalaxy.beans._
  
  new MyBean().set(foo = 10, bar = 12)

• Fx (ScalaDoc) contains an experimental JavaFX DSL (with no runtime dependency) that makes it easy to build objects and define event handlers:

  new Button().set(
    text = bind {
      s"Hello, ${textField.getText}"
    },
    onAction = {
      println("Hello World!")
    }
  )

• Reified (MIGRATED TO ITS OWN REPO) provides a powerful reified values mechanism that deals well with composition and captures of runtime values, allowing for complex ASTs to be generated during runtime for re-compilation or transformation purposes. It preserves the original value that was reified, allowing for flexible mixed usage of runtime value and compile-time AST.

  import scalaxy.reified._
  
  def comp(capture1: Int): ReifiedFunction1[Int, Int] = {
    val capture2 = Seq(10, 20, 30)
    val f = reified((x: Int) => capture1 + capture2(x))
    val g = reified((x: Int) => x * x)
    
    g.compose(f)
  }
  
  println("AST: " + comp(10).expr.tree)

• Obsolete experiments (mostly because of quasiquotes):

  • MacroExtensions provides an extremely simple (and experimental) syntax to define extensions methods as macros:

    @scalaxy.extension[Any] 
    def quoted(quote: String): String = 
      quote + self + quote
      
    @scalaxy.extension[Int] 
    def copiesOf[T : ClassTag](generator: => T): Array[T] = 
      Array.fill[T](self)(generator)
    
    ...
    println(10.quoted("'"))
    // macro-expanded to `"'" + 10 + "'"`
    
    println(3 copiesOf new Entity)
    // macro-expanded to `Array.fill(3)(new Entity)`

  • Compilets provide an easy way to express AST rewrites, backed by a compiler plugin and an sbt plugin.

  • Debug (ScalaDoc) provides assert, require and assume macros that automatically add a useful message to the regular Predef calls. Please prefer Assertions and DiagrammedAssertions from ScalaTest.

Discuss

If you have suggestions / questions:

• @ochafik on Twitter
• NativeLibs4Java mailing-list

You can also file bugs and enhancement requests here.

Any help (testing, patches, bug reports) will be greatly appreciated!

Hacking

• Pushing the site with each sub-project's Scaladoc at http://ochafik.github.io/Scalaxy/:

  sbt clean
  sbt "project scalaxy-doc" ghpages-push-site
  

  (you can preview the site with sbt "project scalaxy-doc" preview-site)

• Publishing projects on Sonatype OSS Repository + advertise on ls.implicit.ly (assuming correct credentials in ~/.sbt/0.13/sonatype.sbt):

  sbt "+ assembly" "+ publish"
  sbt "project scalaxy" ls-write-version lsync