fix #57 implement eval function to evaluate multiple tasks via repl

4 files changed, 36 insertions, 1 deletions

diff --git a/core/src/main/scala/mill/Main.scala b/core/src/main/scala/mill/Main.scala
index 470d9cbc..9d0c328f 100644
--- a/core/src/main/scala/mill/Main.scala
+++ b/core/src/main/scala/mill/Main.scala
@@ -46,6 +46,7 @@ object Main {
             predefCode =
               """import $file.build, build._
                 |implicit val replApplyHandler = mill.main.ReplApplyHandler(build.mapping)
+                |import replApplyHandler.generatedEval._
                 |
               """.stripMargin,
             welcomeBanner = None
diff --git a/core/src/main/scala/mill/main/ReplApplyHandler.scala b/core/src/main/scala/mill/main/ReplApplyHandler.scala
index 3832da68..93e7add4 100644
--- a/core/src/main/scala/mill/main/ReplApplyHandler.scala
+++ b/core/src/main/scala/mill/main/ReplApplyHandler.scala
@@ -25,4 +25,6 @@ class ReplApplyHandler(evaluator: Evaluator[_]) extends ApplyHandler[Task] {
   override def apply[V](t: Task[V]) = {
     evaluator.evaluate(OSet(t)).values.head.asInstanceOf[V]
   }
+
+  val generatedEval = new EvalGenerated(evaluator)
 }
diff --git a/readme.md b/readme.md
index f4887122..aa3acbbc 100644
--- a/readme.md
+++ b/readme.md
@@ -116,6 +116,11 @@ Point(Dependency(com.lihaoyi:ammonite,1.0.3,,Set(),Attributes(,),false,true))
 Scala(Dependency(com.typesafe.play:play-json,2.6.6,,Set(),Attributes(,),false,true))
 Scala(Dependency(org.scala-sbt:zinc,1.0.5,,Set(),Attributes(,),false,true))
 Java(Dependency(org.scala-sbt:test-interface,1.0,,Set(),Attributes(,),false,true))
+
+// run multiple tasks with `eval` function.
+@ val (coreScala, bridge2106Scala) = eval(core.scalaVersion, bridges("2.10.6").scalaVersion)
+coreScala: String = "2.12.4"
+bridge2106Scala: String = "2.10.6"
 ```
 
 ### build.sc
diff --git a/shared.sc b/shared.sc
index 17b82595..579d6b20 100644
--- a/shared.sc
+++ b/shared.sc
@@ -56,6 +56,32 @@ def generateTarget(dir: Path) = {
   )
 }
 
+def generateEval(dir: Path) = {
+  def generate(n: Int) = {
+    val (lowercases, uppercases, typeArgs, zipArgs) = argNames(n)
+    val parameters = lowercases.zip(uppercases).map { case (lower, upper) => s"$lower: TT[$upper]" }.mkString(", ")
+    val extract    = uppercases.zipWithIndex.map { case (t, i) =>  s"result($i).asInstanceOf[$t]" }.mkString(", ")
+
+    s"""def eval[$typeArgs]($parameters):($typeArgs) = {
+       |  val result = evaluator.evaluate(OSet($zipArgs)).values
+       |  (${extract})
+       |}
+     """.stripMargin
+  }
+
+  write(
+    dir / "EvalGenerated.scala",
+    s"""package mill.main
+       |import mill.eval.Evaluator
+       |import mill.define.Task
+       |import mill.util.OSet
+       |class EvalGenerated(evaluator: Evaluator[_]) {
+       |  type TT[+X] = Task[X]
+       |  ${(1 to 22).map(generate).mkString("\n")}
+       |}""".stripMargin
+  )
+}
+
 def generateApplicativeTest(dir: Path) = {
   def generate(n: Int): String = {
     val (lowercases, uppercases, typeArgs, zipArgs) = argNames(n)
@@ -78,6 +104,7 @@ def generateApplicativeTest(dir: Path) = {
 def generateSources(p: Path) = {
   generateApplyer(p)
   generateTarget(p)
+  generateEval(p)
 }
 
 @main
@@ -122,4 +149,4 @@ def downloadBridgeSource(curlDest: Path, crossVersion: String) = {
 
 
   curlDest
-}
\ No newline at end of file
+}