From 66acf364ae3003dd1abb4eeb8759afc6e12aa1a1 Mon Sep 17 00:00:00 2001 From: Eugene Burmako Date: Mon, 7 Jan 2013 07:42:38 +0300 Subject: SI-5903 extractor macros do work Apparently it is already possible to use macros to customize pattern matching as described in the comments to the aforementioned JIRA issue. What's even better - with the incoming addition of c.introduceTopLevel it becomes possible to generate arbitrarily complex unappliers, even with heterogeneous types of arguments varying from expansion to expansion --- test/files/run/macro-expand-unapply-a.check | 2 ++ test/files/run/macro-expand-unapply-a.flags | 1 + .../macro-expand-unapply-a/Impls_Macros_1.scala | 15 +++++++++ test/files/run/macro-expand-unapply-a/Test_2.scala | 6 ++++ test/files/run/macro-expand-unapply-b.check | 2 ++ test/files/run/macro-expand-unapply-b.flags | 1 + .../macro-expand-unapply-b/Impls_Macros_1.scala | 37 ++++++++++++++++++++++ test/files/run/macro-expand-unapply-b/Test_2.scala | 8 +++++ 8 files changed, 72 insertions(+) create mode 100644 test/files/run/macro-expand-unapply-a.check create mode 100644 test/files/run/macro-expand-unapply-a.flags create mode 100644 test/files/run/macro-expand-unapply-a/Impls_Macros_1.scala create mode 100644 test/files/run/macro-expand-unapply-a/Test_2.scala create mode 100644 test/files/run/macro-expand-unapply-b.check create mode 100644 test/files/run/macro-expand-unapply-b.flags create mode 100644 test/files/run/macro-expand-unapply-b/Impls_Macros_1.scala create mode 100644 test/files/run/macro-expand-unapply-b/Test_2.scala (limited to 'test') diff --git a/test/files/run/macro-expand-unapply-a.check b/test/files/run/macro-expand-unapply-a.check new file mode 100644 index 0000000000..7c2976e51e --- /dev/null +++ b/test/files/run/macro-expand-unapply-a.check @@ -0,0 +1,2 @@ +(1,2) +(1,2,3) diff --git a/test/files/run/macro-expand-unapply-a.flags b/test/files/run/macro-expand-unapply-a.flags new file mode 100644 index 0000000000..cd66464f2f --- /dev/null +++ b/test/files/run/macro-expand-unapply-a.flags @@ -0,0 +1 @@ +-language:experimental.macros \ No newline at end of file diff --git a/test/files/run/macro-expand-unapply-a/Impls_Macros_1.scala b/test/files/run/macro-expand-unapply-a/Impls_Macros_1.scala new file mode 100644 index 0000000000..61d6345f16 --- /dev/null +++ b/test/files/run/macro-expand-unapply-a/Impls_Macros_1.scala @@ -0,0 +1,15 @@ +import scala.reflect.macros.Context + +object Helper { + def unapplySeq[T](x: List[T]): Option[Seq[T]] = List.unapplySeq[T](x) +} + +object Macros { + def impl[T: c.WeakTypeTag](c: Context)(x: c.Expr[List[T]]) = { + c.universe.reify(Helper.unapplySeq(x.splice)) + } + + object UnapplyMacro { + def unapplySeq[T](x: List[T]): Option[Seq[T]] = macro impl[T] + } +} \ No newline at end of file diff --git a/test/files/run/macro-expand-unapply-a/Test_2.scala b/test/files/run/macro-expand-unapply-a/Test_2.scala new file mode 100644 index 0000000000..6169d86b19 --- /dev/null +++ b/test/files/run/macro-expand-unapply-a/Test_2.scala @@ -0,0 +1,6 @@ +import Macros._ + +object Test extends App { + List(1, 2) match { case UnapplyMacro(x, y) => println((x, y)) } + List(1, 2, 3) match { case UnapplyMacro(x, y, z) => println((x, y, z)) } +} \ No newline at end of file diff --git a/test/files/run/macro-expand-unapply-b.check b/test/files/run/macro-expand-unapply-b.check new file mode 100644 index 0000000000..5272f0d00a --- /dev/null +++ b/test/files/run/macro-expand-unapply-b.check @@ -0,0 +1,2 @@ +(1,List(2)) +List(1) diff --git a/test/files/run/macro-expand-unapply-b.flags b/test/files/run/macro-expand-unapply-b.flags new file mode 100644 index 0000000000..cd66464f2f --- /dev/null +++ b/test/files/run/macro-expand-unapply-b.flags @@ -0,0 +1 @@ +-language:experimental.macros \ No newline at end of file diff --git a/test/files/run/macro-expand-unapply-b/Impls_Macros_1.scala b/test/files/run/macro-expand-unapply-b/Impls_Macros_1.scala new file mode 100644 index 0000000000..d0300bdf7e --- /dev/null +++ b/test/files/run/macro-expand-unapply-b/Impls_Macros_1.scala @@ -0,0 +1,37 @@ +import language.experimental.macros +import scala.reflect.macros.Context + +object Macros { + implicit class ContextExtensions(c: StringContext) { + object q { + def unapply(x: Any): Option[Any] = macro impl + } + } + + def impl(c: Context)(x: c.Expr[Any]): c.Expr[Option[Any]] = { + import c.universe._ + import Flag._ + + // parts here will be string literals - static parts of the string interpolation + // e.g. for q"$x, $y" parts will be Literal(Constant("")), Literal(Constant(", ")) and Literal(Constant("")) + val Apply(Select(Select(Apply(_, List(Apply(_, parts))), _), _), _) = c.macroApplication + val nresults = parts.length - 1 + + def results() = + ((1 to (nresults - 1)).toList map (i => Literal(Constant(i)))) :+ // (n - 1) results of type Int + Apply(Ident(TermName("List")), List(Literal(Constant(nresults)))) // and also one result of a different type + def extractorBody() = + if (nresults == 0) Literal(Constant(true)) + else if (nresults == 1) Apply(Ident(TermName("Some")), results()) + else Apply(Ident(TermName("Some")), List(Apply(Ident(TermName("Tuple" + nresults)), results()))) + + val name = TermName(java.util.UUID.randomUUID().toString.replace("-", "")) + val mdef = ModuleDef(NoMods, name, Template(List(Select(Ident(TermName("scala")), TypeName("AnyRef"))), emptyValDef, List( + DefDef(Modifiers(), nme.CONSTRUCTOR, List(), List(List()), TypeTree(), + Block(List(pendingSuperCall), Literal(Constant(())))), + DefDef(Modifiers(), TermName("unapply"), List(), List(List(ValDef(Modifiers(PARAM), TermName("x"), Ident(TypeName("Any")), EmptyTree))), TypeTree(), + extractorBody())))) + c.introduceTopLevel(nme.EMPTY_PACKAGE_NAME.toString, mdef) + c.Expr[Option[Any]](Apply(Select(Ident(name), TermName("unapply")), List(x.tree))) + } +} \ No newline at end of file diff --git a/test/files/run/macro-expand-unapply-b/Test_2.scala b/test/files/run/macro-expand-unapply-b/Test_2.scala new file mode 100644 index 0000000000..5352160dfe --- /dev/null +++ b/test/files/run/macro-expand-unapply-b/Test_2.scala @@ -0,0 +1,8 @@ +object Test extends App { + import Macros._ + def whatever() = null + val q"$x1, $y1" = whatever() + println(x1, y1) + val q"$x2" = whatever() + println(x2) +} -- cgit v1.2.3