scala3 feature examples - macros - inline / published by https://github.com/dacr/code-examples-manager #7919a7e2-aafd-4f7f-9702-acd157ef9bfc/5fc690b8f59e434eac9b14f4c0f860e2837c49c7

scala3-feature-macro-0-simple.scala

// summary : scala3 feature examples - macros - inline
// keywords : scala3, tutorial, macros, inline, meta-programming, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 7919a7e2-aafd-4f7f-9702-acd157ef9bfc
// created-on : 2024-03-17T08:32:29+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// Inspired from https://docs.scala-lang.org/scala3/guides/macros/inline.html

//> using scala "3.4.0"

// fully inlined
inline def perimeter(inline radius: Double): Double = {
  2d * math.Pi * radius
}

// TAKE CARE inline parameters should be used only once
//   - to avoid side effect risks
//   - to avoid multiple evaluations : printPerimeter(longCompute())
inline def printPerimeter(inline radius: Double): Unit = {
  println(s"Perimeter(r=$radius)=${perimeter(radius)}")
}

@main def go() = {
  println(perimeter(42d)) // rewritten to : println(263.89378290154264)
  printPerimeter(42d) // rewritten to : Perimeter(r=42.0)=263.89378290154264
}