Swap over to a new, concise `CrossModule[T](..cases)` macro syntax that automatically propagates the `ctx` for you

10 files changed, 90 insertions, 83 deletions

diff --git a/build.sc b/build.sc
index 924cc3dd..a73e3025 100755
--- a/build.sc
+++ b/build.sc
@@ -79,8 +79,8 @@ object core extends MillModule {
 
 val bridgeVersions = Seq("2.10.6", "2.11.8", "2.11.11", "2.12.3", "2.12.4")
 
-object bridges extends CrossModule(BridgeModule, bridgeVersions:_*)
-case class BridgeModule(crossVersion: String, ctx: mill.Module.Ctx) extends mill.Module()(ctx) with PublishModule {
+object bridges extends CrossModule[BridgeModule](bridgeVersions:_*)
+class BridgeModule(crossVersion: String) extends PublishModule {
   def publishName = "mill-bridge"
   def publishVersion = "0.1"
 
@@ -121,8 +121,8 @@ object scalalib extends MillModule {
     }
   }
 }
-object jsbridges extends CrossModule(JsBridgeModule, "0.6", "1.0")
-case class JsBridgeModule(scalajsBinary: String, ctx: mill.Module.Ctx) extends mill.Module()(ctx) with MillModule{
+object jsbridges extends CrossModule[JsBridgeModule]("0.6", "1.0")
+class JsBridgeModule(scalajsBinary: String) extends MillModule{
   def basePath = pwd / 'scalajslib / s"bridge_${scalajsBinary.replace('.', '_')}"
   val scalajsVersion = scalajsBinary match {
     case "0.6" => "0.6.21"
diff --git a/core/src/main/scala/mill/define/Cross.scala b/core/src/main/scala/mill/define/Cross.scala
index 4d68ee62..4b0e1b8f 100644
--- a/core/src/main/scala/mill/define/Cross.scala
+++ b/core/src/main/scala/mill/define/Cross.scala
@@ -1,4 +1,7 @@
 package mill.define
+import language.experimental.macros
+import scala.reflect.ClassTag
+import scala.reflect.macros.{Context, blackbox}
 
 case class Cross[+T](items: List[(List[Any], T)])(implicit val e: sourcecode.Enclosing, val l: sourcecode.Line){
   def flatMap[V](f: T => Cross[V]): Cross[V] = new Cross(
@@ -26,53 +29,62 @@ object Cross{
   def apply[T](t: T*) = new Cross(t.map(i => List(i) -> i).toList)
 }
 
-class CrossModule[T, V](constructor: (T, Module.Ctx) => V, cases: T*)
-                       (implicit ctx: Module.Ctx)
-extends Cross[V]({
-  cases.toList.map(x =>
-    (
-      List(x),
-      constructor(
-        x,
-        ctx.copy(
-          segments0 = Segments(ctx.segments0.value :+ ctx.segment),
-          segment = Segment.Cross(List(x))
-        )
-      )
-    )
-  )
-})
+object CrossModule{
+  def autoCast[A](x: Any): A = x.asInstanceOf[A]
+  abstract class Implicit[T]{
+    def make(v: Any, ctx: Module.Ctx): T
+    def crossValues(v: Any): List[Any]
+  }
+  object Implicit{
+    implicit def make[T]: Implicit[T] = macro makeImpl[T]
+    def makeImpl[T: c.WeakTypeTag](c: blackbox.Context): c.Expr[Implicit[T]] = {
+      import c.universe._
+      val tpe = weakTypeOf[T]
 
-class CrossModule2[T1, T2, V](constructor: (T1, T2, Module.Ctx) => V, cases: (T1, T2)*)
-                             (implicit ctx: Module.Ctx)
-extends Cross[V](
-  cases.toList.map(x =>
-    (
-      List(x._2, x._1),
-      constructor(
-        x._1, x._2,
-        ctx.copy(
-          segments0 = Segments(ctx.segments0.value :+ ctx.segment),
-          segment = Segment.Cross(List(x._2, x._1))
-        )
-      )
-    )
-  )
-)
+      val primaryConstructorArgs =
+        tpe.typeSymbol.asClass.primaryConstructor.typeSignature.paramLists.head
 
-class CrossModule3[T1, T2, T3, V](constructor: (T1, T2, T3, Module.Ctx) => V, cases: (T1, T2, T3)*)
-                                 (implicit ctx: Module.Ctx)
-extends Cross[V](
-  cases.toList.map(x =>
-    (
-      List(x._3, x._2, x._1),
-      constructor(
-        x._1, x._2, x._3,
-        ctx.copy(
-          segments0 = Segments(ctx.segments0.value :+ ctx.segment),
-          segment = Segment.Cross(List(x._3, x._2, x._1))
-        )
+      val tree = primaryConstructorArgs match{
+        case List(arg) =>
+          q"""
+            new mill.define.CrossModule.Implicit[$tpe]{
+              def make(v: Any, ctx0: mill.define.Module.Ctx) = new $tpe(v.asInstanceOf[${arg.info}]){
+                override def ctx = ctx0
+              }
+              def crossValues(v: Any) = List(v)
+            }
+          """
+        case args =>
+          val argTupleValues = for((a, n) <- args.zipWithIndex) yield{
+            q"v.asInstanceOf[scala.Product].productElement($n).asInstanceOf[${a.info}]"
+          }
+          q"""
+            new mill.define.CrossModule.Implicit[$tpe]{
+              def make(v: Any, ctx0: mill.define.Module.Ctx) = new $tpe(..$argTupleValues){
+                override def ctx = ctx0
+              }
+              def crossValues(v: Any) = List(..$argTupleValues)
+            }
+          """
+
+      }
+      c.Expr[Implicit[T]](tree)
+    }
+  }
+}
+class CrossModule[T](cases: Any*)
+                    (implicit ci: CrossModule.Implicit[T],
+                     ctx: Module.Ctx)
+extends Cross[T]({
+  for(c <- cases.toList) yield{
+    val crossValues = ci.crossValues(c)
+    val sub = ci.make(
+      c,
+      ctx.copy(
+        segments0 = Segments(ctx.segments0.value :+ ctx.segment),
+        segment = Segment.Cross(crossValues.reverse)
       )
     )
-  )
-)
\ No newline at end of file
+    (crossValues.reverse, sub)
+  }
+})
\ No newline at end of file
diff --git a/core/src/main/scala/mill/define/Module.scala b/core/src/main/scala/mill/define/Module.scala
index c5837278..9c830c1a 100644
--- a/core/src/main/scala/mill/define/Module.scala
+++ b/core/src/main/scala/mill/define/Module.scala
@@ -20,7 +20,7 @@ case class Segments(value: Seq[Segment])
   * the concrete instance.
   */
 class Module(implicit ctx0: Module.Ctx) extends mill.moduledefs.Cacher{
-  val ctx = ctx0
+  def ctx = ctx0
   // Ensure we do not propagate the implicit parameters as implicits within
   // the body of any inheriting class/trait/objects, as it would screw up any
   // one else trying to use sourcecode.{Enclosing,Line} to capture debug info
diff --git a/core/src/main/scala/mill/package.scala b/core/src/main/scala/mill/package.scala
index b5ab6429..b578ed3b 100644
--- a/core/src/main/scala/mill/package.scala
+++ b/core/src/main/scala/mill/package.scala
@@ -7,7 +7,5 @@ package object mill extends JsonFormatters{
   type PathRef = mill.eval.PathRef
   type Module = define.Module
   val Module = define.Module
-  type CrossModule[T, V] = define.CrossModule[T, V]
-  type CrossModule2[T1, T2, V] = define.CrossModule2[T1, T2, V]
-  type CrossModule3[T1, T2, T3, V] = define.CrossModule3[T1, T2, T3, V]
+  type CrossModule[T] = define.CrossModule[T]
 }
diff --git a/core/src/test/scala/mill/discover/CrossModuleTests.scala b/core/src/test/scala/mill/discover/CrossModuleTests.scala
index 7f5cb89c..ff3b52b1 100644
--- a/core/src/test/scala/mill/discover/CrossModuleTests.scala
+++ b/core/src/test/scala/mill/discover/CrossModuleTests.scala
@@ -14,8 +14,8 @@ object CrossModuleTests extends TestSuite{
 
     'cross - {
       object outer extends TestUtil.BaseModule {
-        object crossed extends mill.CrossModule(CrossedModule, "2.10.6", "2.11.8", "2.12.4")
-        case class CrossedModule(n: String, ctx0: Module.Ctx) extends Module()(ctx0){
+        object crossed extends mill.CrossModule[CrossedModule]("2.10.6", "2.11.8", "2.12.4")
+        class CrossedModule(n: String) extends mill.Module{
           def scalaVersion = n
         }
       }
@@ -42,8 +42,8 @@ object CrossModuleTests extends TestSuite{
           scalaVersion <- Seq("2.10.6", "2.11.8", "2.12.4")
           if !(platform == "native0.3" && scalaVersion == "2.10.6")
         } yield (platform, scalaVersion)
-        object crossed extends mill.CrossModule2(CrossModule, crossMatrix:_*)
-        case class CrossModule(platform: String, scalaVersion: String, ctx0: Module.Ctx) extends mill.Module()(ctx0){
+        object crossed extends mill.CrossModule[CrossModule](crossMatrix:_*)
+        case class CrossModule(platform: String, scalaVersion: String) extends mill.Module{
           def suffix = Seq(scalaVersion, platform).filter(_.nonEmpty).map("_"+_).mkString
         }
       }
diff --git a/core/src/test/scala/mill/util/TestGraphs.scala b/core/src/test/scala/mill/util/TestGraphs.scala
index 95ed8bf0..3ddae02d 100644
--- a/core/src/test/scala/mill/util/TestGraphs.scala
+++ b/core/src/test/scala/mill/util/TestGraphs.scala
@@ -192,8 +192,8 @@ object TestGraphs{
 
 
   object singleCross extends TestUtil.BaseModule {
-    object cross extends mill.CrossModule(CrossModule, "210", "211", "212")
-    case class CrossModule(scalaVersion: String, ctx0: Module.Ctx) extends Module()(ctx0){
+    object cross extends mill.CrossModule[CrossModule]("210", "211", "212")
+    class CrossModule(scalaVersion: String) extends Module{
       def suffix = T{ scalaVersion }
     }
   }
@@ -203,27 +203,27 @@ object TestGraphs{
       platform <- Seq("jvm", "js", "native")
       if !(platform == "native" && scalaVersion != "212")
     } yield (scalaVersion, platform)
-    object cross extends mill.CrossModule2(CrossModule, crossMatrix:_*)
-    case class CrossModule(scalaVersion: String, platform: String, ctx0: Module.Ctx) extends Module()(ctx0){
+    object cross extends mill.CrossModule[CrossModule](crossMatrix:_*)
+    class CrossModule(scalaVersion: String, platform: String) extends Module{
       def suffix = T{ scalaVersion + "_" + platform }
     }
   }
 
   object indirectNestedCrosses extends TestUtil.BaseModule {
-    object cross extends mill.CrossModule(CrossModule, "210", "211", "212")
-    case class CrossModule(scalaVersion: String, ctx0: Module.Ctx) extends mill.Module()(ctx0){
-      object cross2 extends mill.CrossModule(CrossModule, "jvm", "js", "native")
-      case class CrossModule(platform: String, ctx0: Module.Ctx) extends mill.Module{
+    object cross extends mill.CrossModule[CrossModule]("210", "211", "212")
+    class CrossModule(scalaVersion: String) extends mill.Module{
+      object cross2 extends mill.CrossModule[CrossModule]("jvm", "js", "native")
+      class CrossModule(platform: String) extends mill.Module{
         def suffix = T{ scalaVersion + "_" + platform }
       }
     }
   }
 
   object nestedCrosses extends TestUtil.BaseModule {
-    object cross extends mill.CrossModule(CrossModule, "210", "211", "212")
-    case class CrossModule(scalaVersion: String, ctx0: Module.Ctx) extends mill.Module()(ctx0){
-      object cross2 extends mill.CrossModule(CrossModule, "jvm", "js", "native")
-      case class CrossModule(platform: String, ctx0: Module.Ctx) extends mill.Module()(ctx0){
+    object cross extends mill.CrossModule[CrossModule]("210", "211", "212")
+    class CrossModule(scalaVersion: String) extends mill.Module{
+      object cross2 extends mill.CrossModule[CrossModule]("jvm", "js", "native")
+      class CrossModule(platform: String) extends mill.Module{
         def suffix = T{ scalaVersion + "_" + platform }
       }
     }
diff --git a/integration/src/test/resources/acyclic/build.sc b/integration/src/test/resources/acyclic/build.sc
index 91468ad8..942a7c10 100644
--- a/integration/src/test/resources/acyclic/build.sc
+++ b/integration/src/test/resources/acyclic/build.sc
@@ -3,8 +3,8 @@ import mill.CrossModule
 import mill.scalalib.{SbtModule, PublishModule, Dep}
 import mill.scalalib.publish.{PomSettings, License, Developer, SCM}
 
-object acyclic extends CrossModule(AcyclicModule, "2.10.6", "2.11.8", "2.12.3", "2.12.4")
-case class AcyclicModule(crossVersion: String, ctx0: Module.Ctx) extends Module()(ctx0) with SbtModule with PublishModule {
+object acyclic extends CrossModule[AcyclicModule]("2.10.6", "2.11.8", "2.12.3", "2.12.4")
+class AcyclicModule(crossVersion: String) extends SbtModule with PublishModule {
   def basePath = super.basePath / ammonite.ops.up
   def artifactName = "acyclic"
   def publishVersion = "0.1.7"
diff --git a/integration/src/test/resources/jawn/build.sc b/integration/src/test/resources/jawn/build.sc
index c306196c..67b60f05 100644
--- a/integration/src/test/resources/jawn/build.sc
+++ b/integration/src/test/resources/jawn/build.sc
@@ -2,8 +2,8 @@ import mill.scalalib
 import mill.CrossModule
 import mill.scalalib.{Dep, TestModule, Module}
 
-object jawn extends CrossModule(JawnModule, "2.10.6", "2.11.11", "2.12.3")
-case class JawnModule(crossVersion: String, ctx0: mill.Module.Ctx) extends mill.Module()(ctx0) {
+object jawn extends CrossModule[JawnModule]("2.10.6", "2.11.11", "2.12.3")
+class JawnModule(crossVersion: String) extends mill.Module{
   override def basePath = super.basePath / ammonite.ops.up
 
   trait JawnModule extends scalalib.SbtModule{
diff --git a/scalajslib/src/test/scala/mill/scalajslib/HelloJSWorldTests.scala b/scalajslib/src/test/scala/mill/scalajslib/HelloJSWorldTests.scala
index 5c341ebc..5c77efc2 100644
--- a/scalajslib/src/test/scala/mill/scalajslib/HelloJSWorldTests.scala
+++ b/scalajslib/src/test/scala/mill/scalajslib/HelloJSWorldTests.scala
@@ -26,13 +26,11 @@ object HelloJSWorld extends TestUtil.BaseModule {
     scala <- Seq("2.11.8", "2.12.3", "2.12.4")
   } yield (scalaJS, scala)
 
-  object build extends CrossModule2(BuildModule, matrix:_*)
+  object build extends CrossModule[BuildModule](matrix:_*)
 
-  case class BuildModule(scalaJS: String,
-                         scala: String,
-                         ctx0: Module.Ctx) extends Module()(ctx0) with HelloJSWorldModule {
-      def scalaVersion = scala
-      def scalaJSVersion = scalaJS
+  class BuildModule(sjsVersion0: String, scalaVersion0: String) extends HelloJSWorldModule {
+      def scalaVersion = scalaVersion0
+      def scalaJSVersion = sjsVersion0
       def pomSettings = PomSettings(
         organization = "com.lihaoyi",
         description = "hello js world ready for real world publishing",
diff --git a/scalalib/src/test/scala/mill/scalalib/HelloWorldTests.scala b/scalalib/src/test/scala/mill/scalalib/HelloWorldTests.scala
index aaeb96c1..64b5cd42 100644
--- a/scalalib/src/test/scala/mill/scalalib/HelloWorldTests.scala
+++ b/scalalib/src/test/scala/mill/scalalib/HelloWorldTests.scala
@@ -22,9 +22,8 @@ trait HelloWorldModule extends scalalib.Module {
 
 object HelloWorld extends TestUtil.BaseModule with HelloWorldModule
 object CrossHelloWorld extends TestUtil.BaseModule {
-  object cross extends CrossModule(HelloWorldCrossModule, "2.10.6", "2.11.11", "2.12.3", "2.12.4")
-  case class HelloWorldCrossModule(v: String, ctx0: Module.Ctx)
-  extends mill.Module()(ctx0) with HelloWorldModule {
+  object cross extends CrossModule[HelloWorldCrossModule]("2.10.6", "2.11.11", "2.12.3", "2.12.4")
+  class HelloWorldCrossModule(v: String) extends HelloWorldModule {
     def scalaVersion = v
   }
 }