tasty-files-scala-3 (#1457)

* tasty-files-scala-3 * formatting * a feigning hope --------- Co-authored-by: baovitt <[email protected]>
Baeldung · Aug 5, 2024 · aab620a · aab620a
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diff --git a/scala-core-modules/scala-core-9/README.md b/scala-core-modules/scala-core-9/README.md
@@ -6,4 +6,4 @@
 - [Find Two’s Complement of a Number in Scala](https://www.baeldung.com/scala/compute-twos-complement)
 - [Convert Option to Either in Scala](https://www.baeldung.com/scala/option-either-conversion)
 - [Meaning of _root_ In Scala Import Clause](https://www.baeldung.com/scala/root-import-clause)
-- [Check if All Characters in a Scala String Are Either Upper or Lower Case](https://www.baeldung.com/scala/string-check-all-characters-upper-lower-case)
+- [Check if All Characters in a Scala String Are Either Upper or Lower Case](https://www.baeldung.com/scala/string-check-all-characters-upper-lower-case
diff --git a/...a-core-modules/scala-core-9/src/main/scala/com/baeldung/scala/tastyfiles/PowerMacro.scala b/...a-core-modules/scala-core-9/src/main/scala/com/baeldung/scala/tastyfiles/PowerMacro.scala
@@ -0,0 +1,30 @@
+package com.baeldung.scala.tastyfiles
+
+import scala.quoted.*
+
+object PowerMacro:
+  // The macro that unrolls the computation of powers and then generates the expression
+  inline def showAsPowerTerm(inline x: Double, n: Int): String = ${
+    showAsTermImpl('x, 'n)
+  }
+
+  // The actual implementation of the macro
+  private def showAsTermImpl(x: Expr[Double], n: Expr[Int])(using
+    Quotes
+  ): Expr[String] =
+    import quotes.reflect.*
+
+    n.value match
+      case Some(num) =>
+        val powerExpr = unrolledPowerCode(x, num)
+        Expr(
+          powerExpr.asTerm.toString
+        ) // Ensures that the asTerm method call is evaluated at compile-time
+      case None =>
+        '{ "Error: 'n' must be a known constant at compile time." }
+
+  // Helper method to unroll the power computation
+  def unrolledPowerCode(x: Expr[Double], n: Int)(using Quotes): Expr[Double] =
+    if n == 0 then '{ 1.0 }
+    else if n == 1 then x
+    else '{ $x * ${ unrolledPowerCode(x, n - 1) } }
diff --git a/...re-modules/scala-core-9/src/test/scala/com/baeldung/scala/tastyfiles/PowerMacroTest.scala b/...re-modules/scala-core-9/src/test/scala/com/baeldung/scala/tastyfiles/PowerMacroTest.scala
@@ -0,0 +1,15 @@
+package com.baeldung.scala.tastyfiles
+
+import com.baeldung.scala.tastyfiles.*
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class PowerMacroUnitTest extends AnyFlatSpec with Matchers:
+
+  "PowerMacro.showAsPowerTerm" should "generate compile-time term structure" in:
+    val expr: String = PowerMacro.showAsPowerTerm(2.0, 3)
+
+    expr == """
+      Inlined(Ident(PowerMacro$),List(),Apply(Select(Inlined(EmptyTree,List(),Inlined(EmptyTree,List(),Literal(Constant(2.0)))),*),List(Inlined(EmptyTree,List(),Inlined(Ident(PowerMacro$),List(),Apply(Select(Inlined(EmptyTree,List(),Inlined(EmptyTree,List(),Literal(Constant(2.0)))),*),List(Inlined(EmptyTree,List(),Inlined(EmptyTree,List(),Literal(Constant(2.0)))))))))))
+    """.trim