miniboxing/ildl-example

Name: ildl-example

Owner: Scala Miniboxing

Description: Example of using the data-centric metaprogramming plugin.

Created: 2015-08-06 01:55:59.0

Updated: 2015-08-09 17:39:49.0

Pushed: 2015-08-06 02:24:44.0

Homepage: null

Size: 123

Language: Scala

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README

ildl-example

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

To install:

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

In the plugin we have an example transformation:

t src/main/scala/Test.scala 
rt ildl._

ct Test {

*
 Stores Long objects as Ints, losing precision. It's a
 rather dumb transformation, but it shows what's happening.
/
ject 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:
f plus1(v1: Long, v2: Long) = v1 + v2

 transformed method:
rt(RangeReduction) {
def plus2(v1: Long, v2: Long) = v1 + v2


f 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:

t
o] Loading project definition from /mnt/data1/Work/Workspace/dev/ildl-example/project
o] Set current project to ildl-example (in build file:/mnt/data1/Work/Workspace/dev/ildl-example/)

n
o] Running Test 
5 = 9
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.