#ildl-example

This is an example of using data-centric metaprogramming in your sbt project.

To install:

$ git clone https://github.com/miniboxing/ildl-example.git
$ cd ildl-example

In the plugin we have an example transformation:

$ cat src/main/scala/Test.scala import ildl._
object Test {
/**
* Stores Long objects as Ints, losing precision. It's a
* rather dumb transformation, but it shows what's happening.
*/
object RangeReduction extends TransformationDescription {
def toRepr(v: Long): Int @high = v.toInt
def toHigh(v: Int @high): Long = v.toLong
// this method hijacks the + operation on transformed values:
def extension_+(o1: Int @high, o2: Int @high): Int @high = 42
// comment it out to get the right result :)
}
// original method:
def plus1(v1: Long, v2: Long) = v1 + v2
// transformed method:
adrt(RangeReduction) {
def plus2(v1: Long, v2: Long) = v1 + v2
}
def main(args: Array[String]): Unit = {
val v1 = 4
val v2 = 5
println(s"$v1 + $v2 = ${plus1(v1,v2)}")
println(s"$v1 + $v2 = ${plus2(v1,v2)}")
}
}

To run this code:

$ sbt
[info] Loading project definition from /mnt/data1/Work/Workspace/dev/ildl-example/project
[info] Set current project to ildl-example (in build file:/mnt/data1/Work/Workspace/dev/ildl-example/)
> run
[info] Running Test 4 + 5 = 9
4 + 5 = 42

The result will be unexpected. To read more about data-centric metaprogramming check out the scala-ildl.org website or the project wiki.