Replace AsFunction implicit class with Expr.reduce

docs/docs/reference/metaprogramming/macros.md

@@ -135,24 +135,20 @@ expressiveness.
 
 ### From `Expr`s to Functions and Back
 
-The `Expr` companion object contains an implicit `AsFunction` conversion that turns a tree
+The `Expr` companion object contains a `reduce` conversion that turns a tree
 describing a function into a function mapping trees to trees.
 ```scala
 object Expr {
   ...
-  implicit class AsFunction[...](...) { ... }
+  def reduce[...](...)(...): ... =
 }
 ```
-This decorator gives `Expr` the `apply` operation of an applicative functor, where `Expr`s
-over function types can be applied to `Expr` arguments. The definition
-of `AsFunction(f).apply(x)` is assumed to be functionally the same as
+The definition of `Expr.reduce(f)(x)` is assumed to be functionally the same as
 `'{($f)($x)}`, however it should optimize this call by returning the
 result of beta-reducing `f(x)` if `f` is a known lambda expression.
-
-The `AsFunction` decorator distributes applications of `Expr` over function
-arrows:
+`Expr.reduce` distributes applications of `Expr` over function arrows:
 ```scala
-AsFunction(_).apply: Expr[S => T] => (Expr[S] => Expr[T])
+Expr.reduce(_).apply: Expr[(T1, ..., Tn) => R] => ((Expr[T1], ..., Expr[Tn]) => Expr[R])
 ```
 Its dual, let’s call it `reflect`, can be defined as follows:
 ```scala

library/src/scala/quoted/Expr.scala

@@ -28,20 +28,16 @@ package quoted {
     /** Converts a tuple `(T1, ..., Tn)` to `(Expr[T1], ..., Expr[Tn])` */
     type TupleOfExpr[Tup <: Tuple] = Tuple.Map[Tup, [X] =>> (given QuoteContext) => Expr[X]]
 
-    implicit class AsFunction[F, Args <: Tuple, R](f: Expr[F])(given tf: TupledFunction[F, Args => R], qctx: QuoteContext) {
-      /** Beta-reduces the function appication. Generates the an expression only containing the body of the function */
-      def apply[G](given tg: TupledFunction[G, TupleOfExpr[Args] => Expr[R]]): G = {
-        import qctx.tasty._
-        tg.untupled(args => qctx.tasty.internal.betaReduce(f.unseal, args.toArray.toList.map(_.asInstanceOf[QuoteContext => Expr[_]](qctx).unseal)).seal.asInstanceOf[Expr[R]])
-      }
+    /** Beta-reduces the function appication. Generates the an expression only containing the body of the function */
+    def reduce[F, Args <: Tuple, R, G](f: Expr[F])(given tf: TupledFunction[F, Args => R], tg: TupledFunction[G, TupleOfExpr[Args] => Expr[R]], qctx: QuoteContext): G = {
+      import qctx.tasty._
+      tg.untupled(args => qctx.tasty.internal.betaReduce(f.unseal, args.toArray.toList.map(_.asInstanceOf[QuoteContext => Expr[_]](qctx).unseal)).seal.asInstanceOf[Expr[R]])
     }
 
-    implicit class AsContextualFunction[F, Args <: Tuple, R](f: Expr[F])(given tf: TupledFunction[F, (given Args) => R], qctx: QuoteContext) {
-      /** Beta-reduces the function appication. Generates the an expression only containing the body of the function */
-      def apply[G](given tg: TupledFunction[G, TupleOfExpr[Args] => Expr[R]]): G = {
-        import qctx.tasty._
-        tg.untupled(args => qctx.tasty.internal.betaReduce(f.unseal, args.toArray.toList.map(_.asInstanceOf[QuoteContext => Expr[_]](qctx).unseal)).seal.asInstanceOf[Expr[R]])
-      }
+    /** Beta-reduces the function appication. Generates the an expression only containing the body of the function */
+    def reduceGiven[F, Args <: Tuple, R, G](f: Expr[F])(given tf: TupledFunction[F, (given Args) => R], tg: TupledFunction[G, TupleOfExpr[Args] => Expr[R]], qctx: QuoteContext): G = {
+      import qctx.tasty._
+      tg.untupled(args => qctx.tasty.internal.betaReduce(f.unseal, args.toArray.toList.map(_.asInstanceOf[QuoteContext => Expr[_]](qctx).unseal)).seal.asInstanceOf[Expr[R]])
     }
 
     /** Returns a null expresssion equivalent to `'{null}` */

tests/pos/i6783.scala

@@ -1,6 +1,6 @@
 import scala.quoted._
 
-def testImpl(f: Expr[(Int, Int) => Int])(given QuoteContext): Expr[Int] = f('{1}, '{2})
+def testImpl(f: Expr[(Int, Int) => Int])(given QuoteContext): Expr[Int] = Expr.reduce(f)('{1}, '{2})
 
 inline def test(f: (Int, Int) => Int) = ${
   testImpl('f)

tests/run-macros/gestalt-optional-staging/Macro_1.scala

@@ -24,7 +24,7 @@ object Optional {
   // FIXME fix issue #5097 and enable private
   /*private*/ def mapImpl[A >: Null : Type, B >: Null : Type](opt: Expr[Optional[A]], f: Expr[A => B])(given QuoteContext): Expr[Optional[B]] = '{
     if ($opt.isEmpty) new Optional(null)
-    else new Optional(${f('{$opt.value})})
+    else new Optional(${Expr.reduce(f)('{$opt.value})})
   }
 
 }

tests/run-macros/i4734/Macro_1.scala

@@ -13,9 +13,9 @@ object Macros {
     while (i < size) {
       ${
         for (j <- new UnrolledRange(0, unrollSize)) '{
-          val index = i + ${j}
+          val index = i + $j
           val element = ($seq)(index)
-          ${ f('element) } // or `($f)(element)` if `f` should not be inlined
+          ${ Expr.reduce(f)('element) } // or `($f)(element)` if `f` should not be inlined
         }
       }
       i += ${unrollSize}

tests/run-macros/i4735/Macro_1.scala

@@ -17,7 +17,7 @@ object Macro {
       ${
         for (j <- new UnrolledRange(0, unrollSize)) '{
           val element = ($seq)(i + ${j})
-          ${f('element)} // or `($f)(element)` if `f` should not be inlined
+          ${Expr.reduce(f)('element)} // or `($f)(element)` if `f` should not be inlined
         }
       }
       i += ${unrollSize}

tests/run-macros/i7008/macro_1.scala

@@ -15,5 +15,5 @@ def mcrProxy(expr: Expr[Boolean])(given QuoteContext): Expr[Unit] = {
 def mcrImpl[T](func: Expr[Seq[Box[T]] => Unit], expr: Expr[T])(given ctx: QuoteContext, tt: Type[T]): Expr[Unit] = {
   import ctx.tasty._
   val arg = Expr.ofSeq(Seq('{(Box($expr))}))
-  func(arg)
+  Expr.reduce(func)(arg)
 }

tests/run-macros/quote-inline-function/quoted_1.scala

@@ -12,11 +12,11 @@ object Macros {
       var i = $start
       val j = $end
       while (i < j) {
-        ${f.apply('i)}
+        ${Expr.reduce(f)('i)}
         i += 1
       }
       while {
-        ${f.apply('i)}
+        ${Expr.reduce(f)('i)}
         i += 1
         i < j
       } do ()

tests/run-macros/quote-matcher-symantics-2/quoted_1.scala

@@ -72,7 +72,7 @@ object StringNum extends Symantics[String] {
   def value(x: Int)(given QuoteContext): Expr[String] = Expr(x.toString)
   def plus(x: Expr[String], y: Expr[String])(given QuoteContext): Expr[String] = '{ s"${$x} + ${$y}" } // '{ x + " + " + y }
   def times(x: Expr[String], y: Expr[String])(given QuoteContext): Expr[String] = '{ s"${$x} * ${$y}" }
-  def app(f: Expr[String => String], x: Expr[String])(given QuoteContext): Expr[String] = f(x) // functions are beta reduced
+  def app(f: Expr[String => String], x: Expr[String])(given QuoteContext): Expr[String] = Expr.reduce(f)(x)
   def lam(body: Expr[String] => Expr[String])(given QuoteContext): Expr[String => String] = '{ (x: String) => ${body('x)} }
 }
 

tests/run-macros/quote-matching-optimize-1/Macro_1.scala

@@ -9,13 +9,13 @@ object Macro {
 
     def optimize(x: Expr[Any]): Expr[Any] = x match {
       case '{ type $t; ($ls: List[`$t`]).filter($f).filter($g) } =>
-        optimize('{ $ls.filter(x => ${f('x)} && ${g('x)}) })
+        optimize('{ $ls.filter(x => ${Expr.reduce(f)('x)} && ${Expr.reduce(g)('x)}) })
 
       case '{ type $t; type $u; type $v; ($ls: List[`$t`]).map[`$u`]($f).map[`$v`]($g) } =>
-        optimize('{ $ls.map(x => ${g(f('x))}) })
+        optimize('{ $ls.map(x => ${Expr.reduce(g)(Expr.reduce(f)('x))}) })
 
       case '{ type $t; ($ls: List[`$t`]).filter($f).foreach[Unit]($g) } =>
-        optimize('{ $ls.foreach(x => if (${f('x)}) ${g('x)} else ()) })
+        optimize('{ $ls.foreach(x => if (${Expr.reduce(f)('x)}) ${Expr.reduce(g)('x)} else ()) })
 
       case _ => x
     }

tests/run-macros/quote-matching-optimize-2/Macro_1.scala

@@ -11,13 +11,13 @@ object Macro {
 
     def optimize(x: Expr[Any]): Expr[Any] = x match {
       case '{ ($ls: List[$t]).filter($f).filter($g) } =>
-        optimize('{ $ls.filter(x => ${f('x)} && ${g('x)}) })
+        optimize('{ $ls.filter(x => ${Expr.reduce(f)('x)} && ${Expr.reduce(g)('x)}) })
 
       case '{ type $u; type $v; ($ls: List[$t]).map[`$u`]($f).map[`$v`]($g) } =>
-        optimize('{ $ls.map(x => ${g(f('x))}) })
+        optimize('{ $ls.map(x => ${Expr.reduce(g)(Expr.reduce(f)('x))}) })
 
       case '{ ($ls: List[$t]).filter($f).foreach[$u]($g) } =>
-        optimize('{ $ls.foreach[Any](x => if (${f('x)}) ${g('x)} else ()) })
+        optimize('{ $ls.foreach[Any](x => if (${Expr.reduce(f)('x)}) ${Expr.reduce(g)('x)} else ()) })
 
       case _ => x
     }

tests/run-macros/quote-unrolled-foreach/quoted_1.scala

@@ -15,7 +15,7 @@ object Macro {
       println("<log> start loop")
       ${
         @tailrec def loop(j: Int, acc: Expr[Unit]): Expr[Unit] =
-        if (j >= 0) loop(j - 1, '{ ${f('{$seq(i + ${j})})}; $acc })
+        if (j >= 0) loop(j - 1, '{ ${Expr.reduce(f)('{$seq(i + ${j})})}; $acc })
         else acc
         loop(unrollSize - 1, '{})
       }

tests/run-macros/tasty-seal-method/quoted_1.scala

@@ -14,10 +14,10 @@ object Asserts {
         fn.tpe.widen match {
           case Type.IsMethodType(_) =>
             args.size match {
-              case 0 => fn.seal.cast[() => Int].apply()
-              case 1 => fn.seal.cast[Int => Int].apply('{0})
-              case 2 => fn.seal.cast[(Int, Int) => Int].apply('{0}, '{0})
-              case 3 => fn.seal.cast[(Int, Int, Int) => Int].apply('{0}, '{0}, '{0})
+              case 0 => Expr.reduce(fn.seal.cast[() => Int])()
+              case 1 => Expr.reduce(fn.seal.cast[Int => Int])('{0})
+              case 2 => Expr.reduce(fn.seal.cast[(Int, Int) => Int])('{0}, '{0})
+              case 3 => Expr.reduce(fn.seal.cast[(Int, Int, Int) => Int])('{0}, '{0}, '{0})
             }
         }
       case _ => x
@@ -35,10 +35,10 @@ object Asserts {
       case Apply(fn, args) =>
         val pre = rec(fn)
         args.size match {
-          case 0 => pre.seal.cast[() => Any].apply().unseal
-          case 1 => pre.seal.cast[Int => Any].apply('{0}).unseal
-          case 2 => pre.seal.cast[(Int, Int) => Any].apply('{0}, '{0}).unseal
-          case 3 => pre.seal.cast[(Int, Int, Int) => Any].apply('{0}, '{0}, '{0}).unseal
+          case 0 => Expr.reduce(pre.seal.cast[() => Any])().unseal
+          case 1 => Expr.reduce(pre.seal.cast[Int => Any])('{0}).unseal
+          case 2 => Expr.reduce(pre.seal.cast[(Int, Int) => Any])('{0}, '{0}).unseal
+          case 3 => Expr.reduce(pre.seal.cast[(Int, Int, Int) => Any])('{0}, '{0}, '{0}).unseal
         }
       case _ => term
     }

tests/run-macros/tasty-unsafe-let/quoted_1.scala

@@ -12,7 +12,7 @@ object Macros {
 
     import qctx.tasty.{let => letTerm}
     letTerm(rhsTerm) { rhsId =>
-      body(rhsId.seal.asInstanceOf[Expr[T]]).unseal // Dangerous uncheked cast!
+      Expr.reduce(body)(rhsId.seal.asInstanceOf[Expr[T]]).unseal // Dangerous uncheked cast!
     }.seal.cast[Unit]
   }
 

tests/run-staging/i3876-b.scala

@@ -11,7 +11,7 @@ object Test {
       f
     }
 
-    println(run(f2(x)))
-    println(withQuoteContext(f2(x).show))
+    println(run(Expr.reduce(f2)(x)))
+    println(withQuoteContext(Expr.reduce(f2)(x).show))
   }
 }

tests/run-staging/i3876-c.scala

@@ -11,7 +11,7 @@ object Test {
       f
     }
 
-    println(run(f3(x)))
-    println(withQuoteContext(f3(x).show)) // TODO improve printer
+    println(run(Expr.reduce(f3)(x)))
+    println(withQuoteContext(Expr.reduce(f3)(x).show)) // TODO improve printer
   }
 }

tests/run-staging/i3876-d.scala

@@ -9,8 +9,8 @@ object Test {
     def f4(given QuoteContext): Expr[Int => Int] = '{
       inlineLambda
     }
-    println(run(f4(x)))
-    println(withQuoteContext(f4(x).show))
+    println(run(Expr.reduce(f4)(x)))
+    println(withQuoteContext(Expr.reduce(f4)(x).show))
   }
 
   inline def inlineLambda <: Int => Int = x => x + x

tests/run-staging/i3876-e.scala

@@ -9,8 +9,8 @@ object Test {
     def f4(given QuoteContext): Expr[Int => Int] = '{
       inlineLambda
     }
-    println(run(f4(x)))
-    println(withQuoteContext(f4(x).show))
+    println(run(Expr.reduce(f4)(x)))
+    println(withQuoteContext(Expr.reduce(f4)(x).show))
   }
 
   inline def inlineLambda <: Int => Int = x => x + x

tests/run-staging/i3876.scala

@@ -8,7 +8,7 @@ object Test {
 
     def f(given QuoteContext): Expr[Int => Int] = '{ (x: Int) => x + x }
 
-    println(run(f(x)))
-    println(withQuoteContext(f(x).show))
+    println(run(Expr.reduce(f)(x)))
+    println(withQuoteContext(Expr.reduce(f)(x).show))
   }
 }

tests/run-staging/i5144b.scala

@@ -3,7 +3,7 @@ import scala.quoted.staging._
 
 object Test {
   given Toolbox = Toolbox.make(getClass.getClassLoader)
-  def eval1(ff: Expr[Int => Int])(given QuoteContext): Expr[Int] = ff('{42})
+  def eval1(ff: Expr[Int => Int])(given QuoteContext): Expr[Int] = Expr.reduce(ff)('{42})
 
   def peval1()(given QuoteContext): Expr[Unit] = '{
     def f(x: Int): Int = ${eval1('f)}

tests/run-staging/i6281.scala

@@ -27,8 +27,8 @@ object Test extends App {
   }
   // for reify, we need type tags for E and also strangely for L.
   implicit def cons [E, L <: HList](given Effects[L])(given Type[E])(given Type[L])(given QuoteContext): Effects[E :: L] =  new Effects[E :: L] {
-    def reify[A](given Type[A])   = m => '{ k => ${ Effects[L].reify[E] {   m(   a =>    Effects[L].reflect[E]('k(a))) } }}
-    def reflect[A](given Type[A]) = m =>    k =>    Effects[L].reflect[E] { m('{ a => ${ Effects[L].reify[E](   k('a)) } })}
+    def reify[A](given Type[A])   = m => '{ k => ${ Effects[L].reify[E] {   m(   a =>    Effects[L].reflect[E](Expr.reduce('k)(a))) } }}
+    def reflect[A](given Type[A]) = m =>    k =>    Effects[L].reflect[E] { Expr.reduce(m)('{ a => ${ Effects[L].reify[E](   k('a)) } })}
   }
   def Effects[L <: HList](given Effects[L]): Effects[L] = summon[Effects[L]]
 
@@ -45,7 +45,7 @@ object Test extends App {
      val effects = cons[Boolean, RS2](given cons[Int, String :: HNil](given cons[String, HNil](given empty)))
      println(effects.reify[Int] { m }.show)
 
-     val res : Expr[Stm[Int, RS]] = '{ k => ${ Effects[RS2].reify[Boolean] { m(a => Effects[RS2].reflect[Boolean]('k(a))) }}}
+     val res : Expr[Stm[Int, RS]] = '{ k => ${ Effects[RS2].reify[Boolean] { m(a => Effects[RS2].reflect[Boolean](Expr.reduce('k)(a))) }}}
      println(res.show)
   }
 

tests/run-staging/quote-ackermann-1.scala

@@ -15,7 +15,7 @@ object Test {
   def ackermann(m: Int)(given QuoteContext): Expr[Int => Int] = {
     if (m == 0) '{ n => n + 1 }
     else '{ n =>
-      def `ackermann(m-1)`(n: Int): Int = ${ackermann(m - 1)('n)} // Expr[Int => Int] applied to Expr[Int]
+      def `ackermann(m-1)`(n: Int): Int = ${Expr.reduce(ackermann(m - 1))('n)} // Expr[Int => Int] applied to Expr[Int]
       def `ackermann(m)`(n: Int): Int =
         if (n == 0) `ackermann(m-1)`(1) else `ackermann(m-1)`(`ackermann(m)`(n - 1))
       `ackermann(m)`(n)

tests/run-staging/quote-fun-app-1.scala

@@ -12,8 +12,8 @@ object Test {
     println(f(43))
   }
 
-  def f1(given QuoteContext): Expr[Int => Int] = '{ n => ${f2('n)} }
-  def f2(given QuoteContext): Expr[Int => Int] = '{ n => ${f3('n)} }
-  def f3(given QuoteContext): Expr[Int => Int] = '{ n => ${f4('n)} }
+  def f1(given QuoteContext): Expr[Int => Int] = '{ n => ${Expr.reduce(f2)('n)} }
+  def f2(given QuoteContext): Expr[Int => Int] = '{ n => ${Expr.reduce(f3)('n)} }
+  def f3(given QuoteContext): Expr[Int => Int] = '{ n => ${Expr.reduce(f4)('n)} }
   def f4(given QuoteContext): Expr[Int => Int] = '{ n => n }
 }