Merge pull request #10571 from dotty-staging/use-recomended-code-in-docs

Use `unlift`/`unliftOrError` in code examples

Author: nicolasstucki

docs/docs/reference/changed-features/numeric-literals.md

@@ -207,8 +207,8 @@ method in the `FromDigits` given instance. That method is defined in terms of a
 implementation method `fromDigitsImpl`. Here is its definition:
 ```scala
   private def fromDigitsImpl(digits: Expr[String])(using ctx: Quotes): Expr[BigFloat] =
-    digits match {
-      case Const(ds) =>
+    digits.unlift match {
+      case Some(ds) =>
         try {
           val BigFloat(m, e) = apply(ds)
           '{BigFloat(${Expr(m)}, ${Expr(e)})}
@@ -218,7 +218,7 @@ implementation method `fromDigitsImpl`. Here is its definition:
             ctx.error(ex.getMessage)
             '{BigFloat(0, 0)}
         }
-      case digits =>
+      case None =>
         '{apply($digits)}
     }
 } // end BigFloat

docs/docs/reference/metaprogramming/macros.md

@@ -633,25 +633,20 @@ It is possible to deconstruct or extract values out of `Expr` using pattern matc
 
 `scala.quoted` contains objects that can help extracting values from `Expr`.
 
-* `scala.quoted.Const`/`scala.quoted.Consts`: matches an expression of a literal value (or list of values) and returns the value (or list of values).
 * `scala.quoted.Unlifted`: matches an expression of a value (or list of values) and returns the value (or list of values).
+* `scala.quoted.Const`/`scala.quoted.Consts`: Same as `Unlifted` but only works on primitive values.
 * `scala.quoted.Varargs`: matches an explicit sequence of expresions and returns them. These sequences are useful to get individual `Expr[T]` out of a varargs expression of type `Expr[Seq[T]]`.
 
+
 These could be used in the following way to optimize any call to `sum` that has statically known values.
 ```scala
 inline def sum(inline args: Int*): Int = ${ sumExpr('args) }
 private def sumExpr(argsExpr: Expr[Seq[Int]])(using Quotes): Expr[Int] = argsExpr match {
-  case Varargs(Consts(args)) => // args is of type Seq[Int]
+  case Varargs(Unlifted(args)) => // args is of type Seq[Int]
     Expr(args.sum) // precompute result of sum
   case Varargs(argExprs) => // argExprs is of type Seq[Expr[Int]]
-    val staticSum: Int = argExprs.map {
-      case Const(arg) => arg
-      case _ => 0
-    }.sum
-    val dynamicSum: Seq[Expr[Int]] = argExprs.filter {
-      case Const(_) => false
-      case arg => true
-    }
+    val staticSum: Int = argExprs.map(_.unlift.getOrElse(0))
+    val dynamicSum: Seq[Expr[Int]] = argExprs.filter(_.unlift.isEmpty)
     dynamicSum.foldLeft(Expr(staticSum))((acc, arg) => '{ $acc + $arg })
   case _ =>
     '{ $argsExpr.sum }
@@ -688,14 +683,8 @@ private def sumExpr(args1: Seq[Expr[Int]])(using Quotes): Expr[Int] = {
       case arg => Seq(arg)
     }
     val args2 = args1.flatMap(flatSumArgs)
-    val staticSum: Int = args2.map {
-      case Const(arg) => arg
-      case _ => 0
-    }.sum
-    val dynamicSum: Seq[Expr[Int]] = args2.filter {
-      case Const(_) => false
-      case arg => true
-    }
+    val staticSum: Int = args2.map(_.unlift.getOrElse(0)).sum
+    val dynamicSum: Seq[Expr[Int]] = args2.filter(_.unlift.isEmpty)
     dynamicSum.foldLeft(Expr(staticSum))((acc, arg) => '{ $acc + $arg })
 }
 ```
@@ -771,8 +760,8 @@ private def evalExpr(e: Expr[Int])(using Quotes): Expr[Int] = {
       // body: Expr[Int => Int] where the argument represents references to y
       evalExpr(Expr.betaReduce(body)(evalExpr(x)))
     case '{ ($x: Int) * ($y: Int) } =>
-      (x, y) match
-        case (Const(a), Const(b)) => Expr(a * b)
+      (x.unlift, y.unlift) match
+        case (Some(a), Some(b)) => Expr(a * b)
         case _ => e
     case _ => e
   }

tests/neg-macros/BigFloat/BigFloatFromDigitsImpl_1.scala

@@ -5,13 +5,13 @@ import scala.quoted._
 
 object BigFloatFromDigitsImpl:
   def apply(digits: Expr[String])(using Quotes): Expr[BigFloat] =
-    digits match
-      case Const(ds) =>
+    digits.unlift match
+      case Some(ds) =>
         try
           val BigFloat(m, e) = BigFloat(ds)
           '{BigFloat(${Expr(m)}, ${Expr(e)})}
         catch case ex: FromDigits.FromDigitsException =>
           quotes.reflect.report.error(ex.getMessage)
           '{BigFloat(0, 0)}
-      case digits =>
+      case None =>
         '{BigFloat($digits)}

tests/neg-macros/GenericNumLits/EvenFromDigitsImpl_1.scala

@@ -4,8 +4,8 @@ import scala.quoted._
 import Even._
 
 object EvenFromDigitsImpl:
-  def apply(digits: Expr[String])(using Quotes): Expr[Even] = digits match {
-    case Const(ds) =>
+  def apply(digits: Expr[String])(using Quotes): Expr[Even] = digits.unlift match {
+    case Some(ds) =>
       val ev =
         try evenFromDigits(ds)
         catch {

tests/run-macros/BigFloat/BigFloatFromDigitsImpl_1.scala

@@ -5,14 +5,14 @@ import scala.quoted._
 
 object BigFloatFromDigitsImpl:
   def apply(digits: Expr[String])(using Quotes): Expr[BigFloat] =
-    digits match
-      case Const(ds) =>
+    digits.unlift match
+      case Some(ds) =>
         try
           val BigFloat(m, e) = BigFloat(ds)
           '{BigFloat(${Expr(m)}, ${Expr(e)})}
         catch case ex: FromDigits.FromDigitsException =>
           import quotes.reflect.report
           report.error(ex.getMessage)
           '{BigFloat(0, 0)}
-      case digits =>
+      case None =>
         '{BigFloat($digits)}

tests/run-macros/enum-nat-macro/Macros_2.scala

@@ -25,6 +25,6 @@ import Nat._
        case 0 => acc
        case n => inner[Succ[N]](n - 1, '{Succ($acc)})
 
-     val Const(i) = int
+     val i = int.unliftOrError
      require(i >= 0)
      inner[Zero.type](i, '{Zero})

tests/run-macros/flops-rewrite-2/Macro_1.scala

@@ -12,18 +12,18 @@ private def rewriteMacro[T: Type](x: Expr[T])(using Quotes): Expr[T] = {
     postTransform = List(
       Transformation[Int] {
         case '{ plus($x, $y) } =>
-          (x, y) match {
-            case (Const(0), _) => y
-            case (Const(a), Const(b)) => Expr(a + b)
-            case (_, Const(_)) =>  '{ $y + $x }
+          (x.unlift, y.unlift) match {
+            case (Some(0), _) => y
+            case (Some(a), Some(b)) => Expr(a + b)
+            case (_, Some(_)) =>  '{ $y + $x }
             case _ => '{ $x + $y }
           }
         case '{ times($x, $y) } =>
-          (x, y) match {
-            case (Const(0), _) => '{0}
-            case (Const(1), _) => y
-            case (Const(a), Const(b)) => Expr(a * b)
-            case (_, Const(_)) => '{ $y * $x }
+          (x.unlift, y.unlift) match {
+            case (Some(0), _) => '{0}
+            case (Some(1), _) => y
+            case (Some(a), Some(b)) => Expr(a * b)
+            case (_, Some(_)) => '{ $y * $x }
             case _ => '{ $x * $y }
           }
         case '{ power(${Const(x)}, ${Const(y)}) } =>

tests/run-macros/flops-rewrite-3/Macro_1.scala

@@ -11,18 +11,18 @@ private def rewriteMacro[T: Type](x: Expr[T])(using Quotes): Expr[T] = {
   val rewriter = Rewriter().withFixPoint.withPost(
     Transformation.safe[Int] {
       case '{ plus($x, $y) } =>
-        (x, y) match {
-          case (Const(0), _) => y
-          case (Const(a), Const(b)) => Expr(a + b)
-          case (_, Const(_)) =>  '{ $y + $x }
+        (x.unlift, y.unlift) match {
+          case (Some(0), _) => y
+          case (Some(a), Some(b)) => Expr(a + b)
+          case (_, Some(_)) =>  '{ $y + $x }
           case _ => '{ $x + $y }
         }
       case '{ times($x, $y) } =>
-        (x, y) match {
-          case (Const(0), _) => '{0}
-          case (Const(1), _) => y
-          case (Const(a), Const(b)) => Expr(a * b)
-          case (_, Const(_)) => '{ $y * $x }
+        (x.unlift, y.unlift) match {
+          case (Some(0), _) => '{0}
+          case (Some(1), _) => y
+          case (Some(a), Some(b)) => Expr(a * b)
+          case (_, Some(_)) => '{ $y * $x }
           case _ => '{ $x * $y }
         }
       case '{ power(${Const(x)}, ${Const(y)}) } =>

tests/run-macros/i8671/Macro_1.scala

@@ -13,8 +13,8 @@ object FileName {
 
   def createFileName(fileName: Expr[String])(using Quotes): Expr[FileName] =
     import quotes.reflect.report
-    fileName match {
-      case e@Const(s) =>
+    fileName.unlift match {
+      case Some(s) =>
         fileNameFromString(s) match {
             case Right(fn) =>
               '{FileName.unsafe(${Expr(fn.name)})} // Or `Expr(fn)` if there is a `Liftable[FileName]`

tests/run-macros/quote-matcher-string-interpolator-2/quoted_1.scala

@@ -9,8 +9,8 @@ object Macros {
   private def impl(self: Expr[StringContext], args: Expr[Seq[String]])(using Quotes): Expr[String] = {
     (self, args) match {
       case ('{ StringContext(${Varargs(parts)}: _*) }, Varargs(args1)) =>
-        val strParts = parts.map { case Const(str) => str.reverse }
-        val strArgs = args1.map { case Const(str) => str }
+        val strParts = parts.map(_.unliftOrError.reverse)
+        val strArgs = args1.map(_.unliftOrError)
         Expr(StringContext(strParts: _*).s(strArgs: _*))
       case _ => ???
     }

tests/run-macros/quoted-matching-docs-2/Macro_1.scala

@@ -25,13 +25,7 @@ private def sumExpr(args1: Seq[Expr[Int]])(using Quotes): Expr[Int] = {
       case arg => Seq(arg)
     }
     val args2 = args1.flatMap(flatSumArgs)
-    val staticSum: Int = args2.map {
-      case Const(arg) => arg
-      case _ => 0
-    }.sum
-    val dynamicSum: Seq[Expr[Int]] = args2.filter {
-      case Const(_) => false
-      case arg => true
-    }
+    val staticSum: Int = args2.map(_.unlift.getOrElse(0)).sum
+    val dynamicSum: Seq[Expr[Int]] = args2.filter(_.unlift.isEmpty)
     dynamicSum.foldLeft(Expr(staticSum))((acc, arg) => '{ $acc + $arg })
 }

tests/run-macros/quoted-matching-docs/Macro_1.scala

@@ -12,14 +12,8 @@ private def sumExpr(argsExpr: Expr[Seq[Int]])(using Quotes) : Expr[Int] = {
     case Varargs(Consts(args)) => // args is of type Seq[Int]
       Expr(args.sum) // precompute result of sum
     case Varargs(argExprs) => // argExprs is of type Seq[Expr[Int]]
-      val staticSum: Int = argExprs.map {
-        case Const(arg) => arg
-        case _ => 0
-      }.sum
-      val dynamicSum: Seq[Expr[Int]] = argExprs.filter {
-        case Const(_) => false
-        case arg => true
-      }
+      val staticSum: Int = argExprs.map(_.unlift.getOrElse(0)).sum
+      val dynamicSum: Seq[Expr[Int]] = argExprs.filter(_.unlift.isEmpty)
       dynamicSum.foldLeft(Expr(staticSum))((acc, arg) => '{ $acc + $arg })
     case _ =>
       '{ $argsExpr.sum }

tests/run-macros/quoted-pattern-open-expr-simple-eval/Macro_1.scala

@@ -7,8 +7,8 @@ private def evalExpr(using Quotes)(e: Expr[Int]): Expr[Int] = {
     case '{ val y: Int = $x; $body(y): Int } =>
       evalExpr(Expr.betaReduce('{$body(${evalExpr(x)})}))
     case '{ ($x: Int) * ($y: Int) } =>
-      (x, y) match
-        case (Const(a), Const(b)) => Expr(a * b)
+      (x.unlift, y.unlift) match
+        case (Some(a), Some(b)) => Expr(a * b)
         case _ => e
     case _ => e
   }

tests/run-macros/tasty-string-interpolation-reporter-test/Macros_1.scala

@@ -52,7 +52,7 @@ object Macro {
 
   private def fooCore(parts: Seq[Expr[String]], args: Seq[Expr[Any]], reporter: Reporter)(using Quotes): Expr[String] = {
     for ((part, idx) <- parts.zipWithIndex) {
-      val Const(v: String) = part
+      val v = part.unliftOrError
       if (v.contains("#"))
         reporter.errorOnPart("Cannot use #", idx)
     }