scala3 feature examples - macros - inline sizeOf / published by https://github.com/dacr/code-examples-manager #ec61ceb3-1593-4112-9aa9-6ba76fac74cf/c4cfabd54486af8dfc21303e78010db7614f623a

scala3-feature-macro-1-sizeof.scala

// summary : scala3 feature examples - macros - inline sizeOf
// 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 : ec61ceb3-1593-4112-9aa9-6ba76fac74cf
// created-on : 2021-06-20T12:33:40+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// Inspired from https://www.youtube.com/watch?v=OPBuCQRgyV4&t=1283s from Josh Suereth

//> using scala "3.4.0"

import scala.compiletime.erasedValue

inline def sizeOf[T]: Int =
  inline erasedValue[T] match
    case _:Byte   => 1
    case _:Short  => 2
    case _:Int    => 4
    case _:Long   => 8
    case _:Float  => 4
    case _:Double => 8

@main def go() =
  println(s"sizeOf[Int] = ${sizeOf[Int]}")