Merge pull request #71 from eed3si9n/wip/eventlogging

event logging

internal/util-collection/src/main/scala/sbt/internal/util/INode.scala

@@ -95,7 +95,7 @@ abstract class EvaluateSettings[Scope] {
       keyString
 
     private[this] def keyString =
-      (static.toSeq.flatMap { case (key, value) => if (value eq this) init.showFullKey(key) :: Nil else Nil }).headOption getOrElse "non-static"
+      (static.toSeq.flatMap { case (key, value) => if (value eq this) init.showFullKey.show(key) :: Nil else Nil }).headOption getOrElse "non-static"
 
     final def get: T = synchronized {
       assert(value != null, toString + " not evaluated")

internal/util-collection/src/main/scala/sbt/internal/util/Settings.scala

@@ -6,6 +6,7 @@ package sbt.internal.util
 import scala.language.existentials
 
 import Types._
+import sbt.util.Show
 
 sealed trait Settings[Scope] {
   def data: Map[Scope, AttributeMap]
@@ -119,7 +120,7 @@ trait Init[Scope] {
   def mapScope(f: Scope => Scope): MapScoped = new MapScoped {
     def apply[T](k: ScopedKey[T]): ScopedKey[T] = k.copy(scope = f(k.scope))
   }
-  private final class InvalidReference(val key: ScopedKey[_]) extends RuntimeException("Internal settings error: invalid reference to " + showFullKey(key))
+  private final class InvalidReference(val key: ScopedKey[_]) extends RuntimeException("Internal settings error: invalid reference to " + showFullKey.show(key))
 
   private[this] def applyDefaults(ss: Seq[Setting[_]]): Seq[Setting[_]] =
     {
@@ -215,11 +216,11 @@ trait Init[Scope] {
     {
       val guessed = guessIntendedScope(validKeys, delegates, u.referencedKey)
       val derived = u.defining.isDerived
-      val refString = display(u.defining.key)
+      val refString = display.show(u.defining.key)
       val sourceString = if (derived) "" else parenPosString(u.defining)
-      val guessedString = if (derived) "" else guessed.map(g => "\n     Did you mean " + display(g) + " ?").toList.mkString
+      val guessedString = if (derived) "" else guessed.map(g => "\n     Did you mean " + display.show(g) + " ?").toList.mkString
       val derivedString = if (derived) ", which is a derived setting that needs this key to be defined in this scope." else ""
-      display(u.referencedKey) + " from " + refString + sourceString + derivedString + guessedString
+      display.show(u.referencedKey) + " from " + refString + sourceString + derivedString + guessedString
     }
   private[this] def parenPosString(s: Setting[_]): String =
     s.positionString match { case None => ""; case Some(s) => " (" + s + ")" }
@@ -255,7 +256,7 @@ trait Init[Scope] {
       new Uninitialized(keys, prefix + suffix + " to undefined setting" + suffix + ": " + keysString + "\n ")
     }
   final class Compiled[T](val key: ScopedKey[T], val dependencies: Iterable[ScopedKey[_]], val settings: Seq[Setting[T]]) {
-    override def toString = showFullKey(key)
+    override def toString = showFullKey.show(key)
   }
   final class Flattened(val key: ScopedKey[_], val dependencies: Iterable[ScopedKey[_]])
 

internal/util-collection/src/main/scala/sbt/internal/util/Show.scala

@@ -1,8 +0,0 @@
-package sbt.internal.util
-
-trait Show[T] {
-  def apply(t: T): String
-}
-object Show {
-  def apply[T](f: T => String): Show[T] = new Show[T] { def apply(t: T): String = f(t) }
-}

internal/util-collection/src/main/scala/sbt/util/Show.scala

@@ -0,0 +1,12 @@
+package sbt.util
+
+trait Show[A] {
+  def show(a: A): String
+}
+object Show {
+  def apply[A](f: A => String): Show[A] = new Show[A] { def show(a: A): String = f(a) }
+
+  def fromToString[A]: Show[A] = new Show[A] {
+    def show(a: A): String = a.toString
+  }
+}

internal/util-collection/src/main/scala/sbt/util/ShowLines.scala

@@ -1,4 +1,4 @@
-package sbt.internal.util
+package sbt.util
 
 trait ShowLines[A] {
   def showLines(a: A): Seq[String]

internal/util-collection/src/test/scala/SettingsExample.scala

@@ -1,5 +1,7 @@
 package sbt.internal.util
 
+import sbt.util.Show
+
 /** Define our settings system */
 
 // A basic scope indexed by an integer.
@@ -12,9 +14,10 @@ final case class Scope(nestIndex: Int, idAtIndex: Int = 0)
 //  That would be a general pain.)
 case class SettingsExample() extends Init[Scope] {
   // Provides a way of showing a Scope+AttributeKey[_]
-  val showFullKey: Show[ScopedKey[_]] = new Show[ScopedKey[_]] {
-    def apply(key: ScopedKey[_]) = s"${key.scope.nestIndex}(${key.scope.idAtIndex})/${key.key.label}"
-  }
+  val showFullKey: Show[ScopedKey[_]] = Show[ScopedKey[_]]((key: ScopedKey[_]) =>
+    {
+      s"${key.scope.nestIndex}(${key.scope.idAtIndex})/${key.key.label}"
+    })
 
   // A sample delegation function that delegates to a Scope with a lower index.
   val delegates: Scope => Seq[Scope] = {