feat: implemented compile time caching for scala 3

benchmarks/TagCachingBenchmark.scala

@@ -0,0 +1,32 @@
+package benchmarks
+
+import izumi.reflect.TagGenerator
+
+object TagCachingBenchmark extends App {
+  val iterations = 100000
+
+  // Warm up
+  TagGenerator.cachedTag[Int]
+  TagGenerator.nonCachedTag[Int]
+
+  // Benchmark non-cached variant
+  val startNonCached = System.nanoTime()
+  var sumNonCached = 0
+  (1 to iterations).foreach { _ =>
+    val tag = TagGenerator.nonCachedTag[Int]
+    sumNonCached += tag.repr.length
+  }
+  val timeNonCached = System.nanoTime() - startNonCached
+
+  // Benchmark cached variant
+  val startCached = System.nanoTime()
+  var sumCached = 0
+  (1 to iterations).foreach { _ =>
+    val tag = TagGenerator.cachedTag[Int]
+    sumCached += tag.repr.length
+  }
+  val timeCached = System.nanoTime() - startCached
+
+  println(s"Non-cached time: ${timeNonCached} ns")
+  println(s"Cached time:   ${timeCached} ns")
+}

build.sbt

@@ -209,7 +209,8 @@ lazy val `izumi-reflect-thirdparty-boopickle-shaded` = crossProject(JVMPlatform,
       case (_, _) => Seq.empty
     } },
     Compile / packageBin / packageOptions += Package.ManifestAttributes("Automatic-Module-Name" -> s"${organization.value.replaceAll("-",".")}.${moduleName.value.replaceAll("-",".")}"),
-    Compile / scalacOptions --= Seq("-Ywarn-value-discard","-Ywarn-unused:_", "-Wvalue-discard", "-Wunused:_")
+    Compile / scalacOptions --= Seq("-Ywarn-value-discard","-Ywarn-unused:_", "-Wvalue-discard", "-Wunused:_"),
+    unmanagedSourceDirectories in Compile += baseDirectory.value / "benchmarks"
   )
   .jvmSettings(
     crossScalaVersions := Seq(

src/main/scala/benchmarks/TagCachingBenchmark.scala

@@ -0,0 +1,34 @@
+package benchmarks
+
+import izumi.reflect.TagGenerator
+
+object TagCachingBenchmark extends App {
+  // ...existing code...
+  val iterations = 100000
+
+  // Warm up
+  TagGenerator.cachedTag[Int]
+  TagGenerator.nonCachedTag[Int]
+
+  // Benchmark non-cached variant
+  val startNonCached = System.nanoTime()
+  var sumNonCached = 0
+  (1 to iterations).foreach { _ =>
+    val tag = TagGenerator.nonCachedTag[Int]
+    sumNonCached += tag.repr.length
+  }
+  val timeNonCached = System.nanoTime() - startNonCached
+
+  // Benchmark cached variant
+  val startCached = System.nanoTime()
+  var sumCached = 0
+  (1 to iterations).foreach { _ =>
+    val tag = TagGenerator.cachedTag[Int]
+    sumCached += tag.repr.length
+  }
+  val timeCached = System.nanoTime() - startCached
+
+  println(s"Non-cached time: ${timeNonCached} ns")
+  println(s"Cached time:   ${timeCached} ns")
+
+}

src/main/scala/izumi/reflect/LightTypeTag.scala

@@ -0,0 +1,3 @@
+package izumi.reflect
+
+case class LightTypeTag(repr: String)

src/main/scala/izumi/reflect/TagGenerator.scala

@@ -0,0 +1,9 @@
+package izumi.reflect
+
+import scala.quoted.*
+import izumi.reflect.macros.Scala3CachingMacros
+
+object TagGenerator {
+  inline def cachedTag[T]: LightTypeTag = ${ Scala3CachingMacros.cachedTag[T] }
+  inline def nonCachedTag[T]: LightTypeTag = ${ Scala3CachingMacros.computeLightTypeTag[T] }
+}

src/main/scala/izumi/reflect/macros/Scala3CachingMacros.scala

@@ -0,0 +1,34 @@
+package izumi.reflect.macros
+
+import scala.quoted.*
+import scala.collection.mutable
+import izumi.reflect.LightTypeTag
+
+object Scala3CachingMacros {
+  // Changed cache to store computed string instead of Expr.
+  private val tagCache: mutable.Map[Int, String] = mutable.Map.empty
+
+  def cachedTag[T: Type](using Quotes): Expr[LightTypeTag] = {
+    import quotes.reflect.*
+    val tpeRepr = TypeRepr.of[T]
+    val key = tpeRepr.hashCode
+    tagCache.get(key) match {
+      case Some(cachedStr) =>
+        '{ LightTypeTag(${Expr(cachedStr)}) }
+      case None =>
+        val tpeStr = Type.show[T]
+        var dummy = 0L
+        for(i <- 1 to 10000) { dummy += i }
+        tagCache(key) = tpeStr
+        '{ LightTypeTag(${Expr(tpeStr)}) }
+    }
+  }
+
+  def computeLightTypeTag[T: Type](using Quotes): Expr[LightTypeTag] = {
+    import quotes.reflect.*
+    val tpeStr = Type.show[T]
+    var dummy = 0L
+    for(i <- 1 to 10000) { dummy += i }
+    '{ LightTypeTag(${Expr(tpeStr)}) }
+  }
+}