Scala example source code file (TypersTracking.scala)

This example Scala source code file (TypersTracking.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

collection, compiler, context, list, mode, nil, nsc, reflection, string, t, tree, type, typetree, unit, utilities

The TypersTracking.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2005-2013 LAMP/EPFL
 * @author  Paul Phillips
 */

package scala.tools.nsc
package typechecker

import scala.collection.mutable
import scala.reflect.internal.util.{ BatchSourceFile, Statistics }
import mutable.ListBuffer
import Mode._

trait TypersTracking {
  self: Analyzer =>

  import global._
  import typeDebug._

  // To enable decent error messages when the typer crashes.
  // TODO - this only catches trees which go through def typed,
  // but there are all kinds of back ways - typedClassDef, etc. etc.
  // Funnel everything through one doorway.
  var lastTreeToTyper: Tree = EmptyTree

  def fullSiteString(context: Context): String = {
    def owner_long_s = (
      if (settings.debug.value) {
        def flags_s = context.owner.debugFlagString match {
          case "" => ""
          case s  => " with flags " + inLightMagenta(s)
        }
        s", a ${context.owner.shortSymbolClass}$flags_s"
      }
      else ""
    )
    def marker = if (context.bufferErrors) "silent" else "site"
    def undet_s = context.undetparams match {
      case Nil => ""
      case ps  => ps.mkString(" solving: ", ",", "")
    }
    def implicits_s = (
      if (context.enrichmentEnabled)
        if (context.implicitsEnabled) ""
        else inLightRed("enrichment only")
      else inLightRed("implicits disabled")
    )

    s"($marker$undet_s: ${context.siteString}$owner_long_s) $implicits_s"
  }

  object typingStack {
    val out = new java.io.PrintWriter(System.err, true)

    // TODO - account for colors so the color of a multiline string
    // doesn't infect the connector lines
    private def currentIndent = "|    " * depth

    private var trees: List[Frame] = Nil
    private var depth = 0
    private def atLowerIndent[T](body: => T): T = {
      depth -= 1
      try body finally depth += 1
    }
    private def resetIfEmpty(s: String) = if (trees.isEmpty) resetColor(s) else s

    private def truncAndOneLine(s: String): String = {
      val s1 = s.replaceAll("\\s+", " ")
      if (s1.length < 60 || settings.debug.value) s1 else s1.take(57) + "..."
    }

    private class Frame(val tree: Tree) { }
    private def greenType(tp: Type): String = tpe_s(tp, inGreen)
    private def greenType(tree: Tree): String = tree match {
      case null                              => "[exception]"
      case md: MemberDef if md.tpe == NoType => inBlue(s"[${md.keyword} ${md.name}]") + " " + greenType(md.symbol.tpe)
      case _ if tree.tpe.isComplete          => greenType(tree.tpe)
      case _                                 => "<?>"
    }
    def indented(s: String): String =
      if (s == "") "" else currentIndent + s.replaceAll("\n", "\n" + currentIndent)

    @inline final def runWith[T](t: Tree)(body: => T): T = {
      push(t)
      try body finally pop(t)
    }
    def push(t: Tree): Unit = {
      trees ::= new Frame(t)
      depth += 1
    }
    def pop(t: Tree): Unit = {
      val frame = trees.head
      assert(frame.tree eq t, ((frame.tree, t)))
      trees = trees.tail
      depth -= 1
    }
    def show(s: String)     { if (s != "") out.println(s) }

    def showPush(tree: Tree, context: Context) {
      showPush(tree, NOmode, WildcardType, context)
    }
    def showPush(tree: Tree, mode: Mode, pt: Type, context: Context) {
      def tree_s = truncAndOneLine(ptTree(tree))
      def pt_s = if (pt.isWildcard || context.inTypeConstructorAllowed) "" else s": pt=$pt"
      def all_s = List(tree_s, pt_s, mode, fullSiteString(context)) filterNot (_ == "") mkString " "

      atLowerIndent(show(indented("""|-- """ + all_s)))
    }
    def showPop(typedTree: Tree): Tree = {
      val s = greenType(typedTree)
      show(resetIfEmpty(indented("""\-> """ + s)))
      typedTree
    }
    def showAdapt(original: Tree, adapted: Tree, pt: Type, context: Context) {
      if (!noPrintAdapt(original, adapted)) {
        def tree_s1 = inLightCyan(truncAndOneLine(ptTree(original)))
        def pt_s = if (pt.isWildcard) "" else s" based on pt $pt"
        def tree_s2 = adapted match {
          case tt: TypeTree => "is now a TypeTree(" + tpe_s(tt.tpe, inCyan) + ")"
          case _            => "adapted to " + inCyan(truncAndOneLine(ptTree(adapted))) + pt_s
        }
        show(indented(s"[adapt] $tree_s1 $tree_s2"))
      }
    }
    def showTyped(tree: Tree) {
      def class_s = tree match {
        case _: RefTree => ""
        case _          => " " + tree.shortClass
      }
      if (!noPrintTyping(tree))
        show(indented(s"[typed$class_s] " + truncAndOneLine(ptTree(tree))))
    }

    def nextTyped(tree: Tree, mode: Mode, pt: Type, context: Context)(body: => Tree): Tree =
      nextTypedInternal(tree, showPush(tree, mode, pt, context))(body)

    def nextTypedInternal(tree: Tree, pushFn: => Unit)(body: => Tree): Tree = (
      if (noPrintTyping(tree))
        body
      else
        runWith(tree) { pushFn ; showPop(body) }
    )

    @inline final def printTyping(tree: Tree, s: => String) = {
      if (printTypings && !noPrintTyping(tree))
        show(indented(s))
    }
    @inline final def printTyping(s: => String) = {
      if (printTypings)
        show(indented(s))
    }
  }
  def tpe_s(tp: Type, colorize: String => String): String = tp match {
    case OverloadedType(pre, alts) => alts map (alt => tpe_s(pre memberType alt, colorize)) mkString " <and> "
    case _                         => colorize(tp.toLongString)
  }
  // def sym_s(s: Symbol) = if (s eq null) "" + s else s.getClass.getName split '.' last;

  // Some trees which are typed with mind-numbing frequency and
  // which add nothing by being printed. Did () type to Unit? Let's
  // gamble on yes.
  private def printingOk(t: Tree) = printTypings && (settings.debug.value || !noPrint(t))
  def noPrintTyping(t: Tree) = (t.tpe ne null) || !printingOk(t)
  def noPrintAdapt(tree1: Tree, tree2: Tree) = !printingOk(tree1) || (
       (tree1.tpe == tree2.tpe)
    && (tree1.symbol == tree2.symbol)
  )
}