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Switchable matches with string-typed scrutinee survive the pattern matcher in the same way as those on integer types do: as a series of `CaseDef`s with empty guard and literal pattern. Cleanup collates them by hash code and emits a switch on that. No sooner, so scala.js can emit a more JS-friendly implementation. Labels were used to avoid a proliferation of `throw new MatchError`. Works with nulls. Works with Unit. Enclosed "pos" test stands for positions, not positivity. Fixes scala/bug#11740
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,7 @@ | ||
| import annotation.switch | ||
| class Switches { | ||
| val cond = true | ||
| def two = ("foo" : @switch) match { case "foo" => case "bar" => } | ||
| def guard = ("foo" : @switch) match { case "z" => case "y" => case x if cond => } | ||
| def colli = ("foo" : @switch) match { case "DB" => case "Ca" => } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,16 @@ | ||
| import scala.tools.partest.BytecodeTest | ||
| import scala.tools.asm | ||
| import scala.collection.JavaConverters._ | ||
| import scala.PartialFunction.cond | ||
|
|
||
| object Test extends BytecodeTest { | ||
| def show: Unit = { | ||
| val clasz = loadClassNode("Switches") | ||
| List("two", "guard", "colli") foreach { meth => | ||
| val mn = getMethod(clasz, meth) | ||
| assert(mn.instructions.iterator.asScala.exists(isSwitchInsn), meth) | ||
| } | ||
| } | ||
| def isSwitchInsn(insn: asm.tree.AbstractInsnNode) = | ||
| cond(insn.getOpcode) { case asm.Opcodes.LOOKUPSWITCH | asm.Opcodes.TABLESWITCH => true } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,2 @@ | ||
| 2 | ||
| -1 |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,16 @@ | ||
| import annotation.switch | ||
|
|
||
| object Test { | ||
| def test(s: String): Int = { | ||
| (s : @switch) match { | ||
| case "1" => 0 | ||
| case null => -1 | ||
| case _ => s.toInt | ||
| } | ||
| } | ||
|
|
||
| def main(args: Array[String]): Unit = { | ||
| println(test("2")) | ||
| println(test(null)) | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,64 @@ | ||
| [[syntax trees at end of patmat]] // newSource1.scala | ||
| [6]package [6]<empty> { | ||
| [6]class Switch extends [13][187]scala.AnyRef { | ||
| [187]def <init>(): [13]Switch = [187]{ | ||
| [187][187][187]Switch.super.<init>(); | ||
| [13]() | ||
| }; | ||
| [21]def switch([28]s: [31]<type: [31]scala.Predef.String>, [39]cond: [45]<type: [45]scala.Boolean>): [21]Int = [56]{ | ||
| [56]case <synthetic> val x1: [56]String = [56]s; | ||
| [56][56]x1 match { | ||
| [56]case [75]"AaAa" => [93]1 | ||
| [56]case [104]"asdf" => [122]2 | ||
| [133]case [133]"BbBb" => [133]if ([143]cond) | ||
| [151]3 | ||
| else | ||
| [180]4 | ||
| [56]case [56]_ => [56]throw [56][56][56]new [56]MatchError([56]x1) | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| [[syntax trees at end of cleanup]] // newSource1.scala | ||
| [6]package [6]<empty> { | ||
| [6]class Switch extends [13][13]Object { | ||
| [21]def switch([28]s: [31]<type: [31]scala.Predef.String>, [39]cond: [45]<type: [45]scala.Boolean>): [21]Int = [56]{ | ||
| [56]case <synthetic> val x1: [56]String = [56]s; | ||
| [56]{ | ||
| [56][56]matchEnd1([56][56]if ([56][56]x1.eq([56]null)) | ||
| [56]0 | ||
| else | ||
| [56][56]x1.hashCode() match { | ||
| [56]case [56]2031744 => [75]if ([75][75][75]"AaAa".equals([75]x1)) | ||
| [93]1 | ||
| else | ||
| [56][56]matchEnd2() | ||
| [56]case [56]2062528 => [133]if ([133][133][133]"BbBb".equals([133]x1)) | ||
| [133]if ([143]cond) | ||
| [151]3 | ||
| else | ||
| [180]4 | ||
| else | ||
| [56][56]matchEnd2() | ||
| [56]case [56]3003444 => [104]if ([104][104][104]"asdf".equals([104]x1)) | ||
| [122]2 | ||
| else | ||
| [56][56]matchEnd2() | ||
| [56]case [56]_ => [56][56]matchEnd2() | ||
| }); | ||
| [56]matchEnd2(){ | ||
| [56]throw [56][56][56]new [56]MatchError([56]x1) | ||
| }; | ||
| [56]matchEnd1(x$1: [NoPosition]Int){ | ||
| [56]x$1 | ||
| } | ||
| } | ||
| }; | ||
| [187]def <init>(): [13]Switch = [187]{ | ||
| [187][187][187]Switch.super.<init>(); | ||
| [13]() | ||
| } | ||
| } | ||
| } | ||
|
|
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,18 @@ | ||
| import scala.tools.partest._ | ||
|
|
||
| object Test extends DirectTest { | ||
| override def extraSettings: String = "-usejavacp -stop:cleanup -Vprint:patmat,cleanup -Vprint-pos" | ||
|
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| override def code = | ||
| """class Switch { | ||
| | def switch(s: String, cond: Boolean) = s match { | ||
| | case "AaAa" => 1 | ||
| | case "asdf" => 2 | ||
| | case "BbBb" if cond => 3 | ||
| | case "BbBb" => 4 | ||
| | } | ||
| |} | ||
| """.stripMargin.trim | ||
|
|
||
| override def show(): Unit = Console.withErr(Console.out) { super.compile() } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,20 @@ | ||
| fido Success(dog) | ||
| garfield Success(cat) | ||
| wanda Success(fish) | ||
| henry Success(horse) | ||
| felix Failure(scala.MatchError: felix (of class java.lang.String)) | ||
| deuteronomy Success(cat) | ||
| ===== | ||
| AaAa 2031744 Success(1) | ||
| BBBB 2031744 Success(2) | ||
| BBAa 2031744 Failure(scala.MatchError: BBAa (of class java.lang.String)) | ||
| cCCc 3015872 Success(3) | ||
| ddDd 3077408 Success(4) | ||
| EEee 2125120 Failure(scala.MatchError: EEee (of class java.lang.String)) | ||
| ===== | ||
| A Success(()) | ||
| X Failure(scala.MatchError: X (of class java.lang.String)) | ||
| ===== | ||
| Success(3) | ||
| null Failure(scala.MatchError: null) | ||
| 7 Failure(scala.MatchError: 7 (of class java.lang.String)) |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,46 @@ | ||
| // scalac: -Werror | ||
| import annotation.switch | ||
| import util.Try | ||
|
|
||
| object Test extends App { | ||
|
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| def species(name: String) = (name.toLowerCase : @switch) match { | ||
| case "fido" => "dog" | ||
| case "garfield" | "deuteronomy" => "cat" | ||
| case "wanda" => "fish" | ||
| case "henry" => "horse" | ||
| } | ||
| List("fido", "garfield", "wanda", "henry", "felix", "deuteronomy").foreach { n => println(s"$n ${Try(species(n))}") } | ||
|
|
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| println("=====") | ||
|
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| def collide(in: String) = (in : @switch) match { | ||
| case "AaAa" => 1 | ||
| case "BBBB" => 2 | ||
| case "cCCc" => 3 | ||
| case x if x == "ddDd" => 4 | ||
| } | ||
| List("AaAa", "BBBB", "BBAa", "cCCc", "ddDd", "EEee").foreach { s => | ||
| println(s"$s ${s.##} ${Try(collide(s))}") | ||
| } | ||
|
|
||
| println("=====") | ||
|
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| def unitary(in: String) = (in : @switch) match { | ||
| case "A" => | ||
| } | ||
| List("A","X").foreach { s => | ||
| println(s"$s ${Try(unitary(s))}") | ||
| } | ||
|
|
||
| println("=====") | ||
|
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| def nullFun(in: String) = (in : @switch) match { | ||
| case "1" => 1 | ||
| case null => 2 | ||
| case "" => 3 | ||
| } | ||
| List("", null, "7").foreach { s => | ||
| println(s"$s ${Try(nullFun(s))}") | ||
| } | ||
| } |