Getting type information inside scala repl via IMain

Question

Intent I am trying to add support for `:kind` command to scala repl. Thanks to Eugene Burmako, I was able to get a working prototype. Though it only works with fully qualified names and fails to resolve imported names. I am now trying to use `IMain.exprTyper` to do the job, as it is aware of types, imported into the repl. But there is a problem. Everything I've tried returns a `ClassInfoType` like the following (displayed with `showRaw`): ``` ClassInfoType(List(TypeRef(TypeRef(TypeRef(TypeRef(NoPrefix(), package , List()), package java, List()), package lang, List()), class Object, List()), TypeRef(TypeRef(TypeRef(NoPrefix(), package , List()), package scala, List()), trait Serializable, List())), Scope{ def (): Option.type; implicit def option2Iterable(xo: Option): Iterable; def apply(x: Object): Option; def empty(): Option; private def readResolve(): Object }, object Option) ``` While the working implementation returns specific `Type`: ``` PolyType(List(TypeName("A…

Accepted Answer

How about this? I'm using power mode which gives you access to the global from the currently running REPL, which is a shade more convenient than creating a new `IMain`. ``` scala> :power Already in power mode. scala> val g = global g: $r.intp.global.type = scala> val context = g.analyzer.rootContext(NoCompilationUnit) context: g.analyzer.Context = Context(@EmptyTree unit=NoCompilationUnit scope=997093283 errors=false, reportErrors=true, throwErrors=false) // aware imports of scala._, etc. scala> val sym = context.lookupSymbol("Option": TypeName, _ => true).symbol sym: g.analyzer.global.Symbol = class Option scala> sym.tpeHK.typeParams res21: List[g.analyzer.global.Symbol] = List(type A) ``` See also: ``` scala> intp.symbolOfType("Foo") res26: $r.intp.global.Symbol = class Foo ``` But I'm not sure how to get at previously imported symbols: ``` scala> object Bar { class Bop } defined object Bar scala> import Bar.Bop import Bar.Bop scala> intp.symbolOfType("Bop") res27: $r.intp.global.Symbol = ``` Edit: The reason OP's getting `ClassInfoType` instead of `PolyType` is due to phase. To get the same result as the power mode's `global`, one must set the phase to `typer`. To quote @retronym's explanation from REPL: intp.global vs "global" available in :power mode: ``` scala> :power ** Power User mode enabled - BEEP WHIR GYVE ** ** :phase has been set to 'typer'. ** ^ `---- this part is relevant ``` Symbols have an list of types (aka `info`-s), indexed by compiler phase. (aka TypeHistory). Many compiler phases install `InfoTransformer`s to morph the type. See src/compiler/scala/tools/nsc/transform/InfoTransform.scala for some documentation. To inspect the type as-at particular phase, you can use methods like 'exitingTyper`. ``` scala> exitingPostErasure($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 ```

Getting type information inside scala repl via IMain

Solution

Problem