REPL: intp.global vs "global" available in :power mode (ClassInfoType problem)

[Eugene Yokota]

Hi guys,

Is there a difference in the way intp.global behave as opposed to global object

I can get hold of in :power mode of the REPL?

While working on [:kind command][1]. I'm getting stuck with the same point @folone got stuck:

- [Adding :kind command to scala repl][2]

- [Getting type information inside scala repl via IMain][3]

1. For several reasons, I would like to use global instead of the runtime.universe.

2. In this discussion, let's assume I have the full name of the type.

I was able to port Adriaan's inferKind to trait Kinds, and get it work in :power mode:

scala> :power

scala> global.inferKind(NoPrefix)(intp.global.rootMirror.staticClass("scala.Option"))

[+A]AnyRef

        with Product

        with Serializable {

  def <init>(): Option[A]

  def isEmpty: Boolean

  def isDefined: Boolean

  def get: A

  final def getOrElse[B >: A](default: => B): B

  final def orNull[A1 >: A](implicit ev: <:<[Null,A1]): A1

  final def map[B](f: A => B): Option[B]

  final def fold[B](ifEmpty: => B)(f: A => B): B

  final def flatMap[B](f: A => Option[B]): Option[B]

  def flatten[B](implicit ev: <:<[A,Option[B]]): Option[B]

  final def filter(p: A => Boolean): Option[A]

  final def filterNot(p: A => Boolean): Option[A]

  final def nonEmpty: Boolean

  final def withFilter(p: A => Boolean): Option.this.WithFilter

  class WithFilter extends AnyRef

  final def contains[A1 >: A](elem: A1): Boolean

  final def exists(p: A => Boolean): Boolean

  final def forall(p: A => Boolean): Boolean

  final def foreach[U](f: A => U): Unit

  final def collect[B](pf: PartialFunction[A,B]): Option[B]

  final def orElse[B >: A](alternative: => Option[B]): Option[B]

  def iterator: Iterator[A]

  def toList: List[A]

  final def toRight[X](left: => X): Product with Serializable with scala.util.Either[X,A]

  final def toLeft[X](right: => X): Product with Serializable with scala.util.Either[A,X]

}

class scala.reflect.internal.Types$PolyType

class scala.reflect.internal.Types$UniqueTypeBounds

res0: $r.global.Kind = F[+A]

I am doing some println of the Types to check what's going on. In the above I'm getting PolyType as expected.

:kind command does the same thing, but here's what I get.

scala> :kind scala.Option

typeFromFullName

Object

        with Product

        with Serializable {

  def <init>(): Option

  def isEmpty(): Boolean

  def isDefined(): Boolean

  def get(): Object

  final def getOrElse(default: Function0): Object

  final def orNull(ev: less:<): Object

  final def map(f: Function1): Option

  final def fold(ifEmpty: Function0,f: Function1): Object

  final def flatMap(f: Function1): Option

  def flatten(ev: less:<): Option

  final def filter(p: Function1): Option

  final def filterNot(p: Function1): Option

  final def nonEmpty(): Boolean

  final def withFilter(p: Function1): Option#Option$WithFilter

  final def contains(elem: Object): Boolean

  final def exists(p: Function1): Boolean

  final def forall(p: Function1): Boolean

  final def foreach(f: Function1): Unit

  final def collect(pf: PartialFunction): Option

  final def orElse(alternative: Function0): Option

  def iterator(): Iterator

  def toList(): List

  final def toRight(left: Function0): util.Either

  final def toLeft(right: Function0): util.Either

}

class scala.reflect.internal.Types$ClassInfoType

A

Instead of PolyType, I get ClassInfoType. What am I doing wrong here?

The code that's converting the type symbol to Type is this:

    abstract class InferKind {

      def apply(tpe: Type, owner: Symbol): Kind

      def apply(sym: Symbol): Kind = apply(sym.typeSignature, sym.owner)

    }

-eugene

  [1]: https://github.com/scala/scala/pull/2340

  [2]: https://groups.google.com/d/msg/scala-internals/DdSg-qxOvyo/-C7XrgAUgtwJ

  [3]: http://stackoverflow.com/a/15694003/3827

[Paul Phillips]

On Sun, Apr 7, 2013 at 12:31 PM, Eugene Yokota <eed3...@gmail.com> wrote:

Is there a difference in the way intp.global behave as opposed to global object

I can get hold of in :power mode of the REPL?

They're the same object.

scala> $intp.global

res0: scala.tools.nsc.Global = <global>

scala> :power

** Power User mode enabled - BEEP WHIR GYVE **

** :phase has been set to 'typer'.          **

** scala.tools.nsc._ has been imported      **

** global._, definitions._ also imported    **

** Try  :help, :vals, power.<tab>           **

scala> global

res1: $r.intp.global.type = <global>

scala> res0 eq res1

res2: Boolean = true

[eugene yokota]

On Sun, Apr 7, 2013 at 5:09 PM, Paul Phillips <pa...@improving.org> wrote:

They're the same object.

Here's a simple repro. Am I missing some implicits?

scala> $intp.global.rootMirror.staticClass("scala.Option").typeSignature.getClass

res0: Class[_ <: $intp.global.Type] = class scala.reflect.internal.Types$ClassInfoType

scala> :power

** Power User mode enabled - BEEP WHIR GYVE **

** :phase has been set to 'typer'.          **

** scala.tools.nsc._ has been imported      **

** global._, definitions._ also imported    **

** Try  :help, :vals, power.<tab>           **

scala> global.rootMirror.staticClass("scala.Option").typeSignature.getClass

res1: Class[_ <: $r.global.Type] = class scala.reflect.internal.Types$PolyType

scala> $intp.global eq global

res2: Boolean = true

-eugene

[Jason Zaugg]

On Sun, Apr 7, 2013 at 11:42 PM, eugene yokota <eed3...@gmail.com> wrote:

On Sun, Apr 7, 2013 at 5:09 PM, Paul Phillips <pa...@improving.org> wrote:

They're the same object.

Here's a simple repro. Am I missing some implicits?

scala> $intp.global.rootMirror.staticClass("scala.Option").typeSignature.getClass

res0: Class[_ <: $intp.global.Type] = class scala.reflect.internal.Types$ClassInfoType

scala> :power

** Power User mode enabled - BEEP WHIR GYVE **

** :phase has been set to 'typer'.          **

     ^

     `----  this part is relevant

Symbols have an list of types (aka 'info'-s), indexed by compiler phase. (aka TypeHistory). Many compiler phases install 'InfoTransformers' to morph the type. See src/compiler/scala/tools/nsc/transform/InfoTransform.scala for some documentation.

To inspect the type as-at particular phase, you can use methods like 'exitingTyper`.

scala> exitingPostErasure($intp.global.rootMirror.staticClass("scala.Option").typeSignature).getClass

res6: Class[_ <: $intp.global.Type] = class scala.reflect.internal.Types$ClassInfoType

scala> exitingTyper($intp.global.rootMirror.staticClass("scala.Option").typeSignature).getClass

res7: Class[_ <: $intp.global.Type] = class scala.reflect.internal.Types$PolyType

Or, a little more conveniently in :power mode:

scala> :phase typer

Active phase is now: Typer

scala> global.rootMirror.staticClass("scala.Option").typeSignature.getClass

res16: Class[_ <: $r.global.Type] = class scala.reflect.internal.Types$PolyType

scala> :phase cleanup

Active phase is now: Cleanup

scala> global.rootMirror.staticClass("scala.Option").typeSignature.getClass

res17: Class[_ <: $r.global.Type] = class scala.reflect.internal.Types$ClassInfoType

-jason          

[eugene yokota]

The phase! That makes sense now. Thanks!

-eugene

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[Eugene Burmako]

Wow!!! That's very helpful. I remember stumbling upon this problem
some time ago. Didn't figure it out back then.

On Apr 8, 1:10 am, eugene yokota <eed3s...@gmail.com> wrote:
> The phase! That makes sense now. Thanks!
>
> -eugene
>
>
>
>
>
>
>
> On Sun, Apr 7, 2013 at 6:02 PM, Jason Zaugg <jza...@gmail.com> wrote:

> >https://groups.google.com/d/topic/scala-internals/fBLwvcjNGTc/unsubsc...
> > .