[WIP] support operator interception for non-literal types

[erikerlandson]

goal is to support the ability for OpMacro to attempt a call to implicitly[OpIntercept[op, arg, arg...]] when it cannot resolve an operator with its arguments. See discussion on #140.

[erikerlandson]

Example run of current code:

scala> import singleton.ops.impl._, singleton.ops.impl.Rig._
import singleton.ops.impl._
import singleton.ops.impl.Rig._

scala> implicitly[Add[Rig[2], Rig[3]]]
usingFuncName: opTpe= singleton.ops.impl.OpMacro[singleton.ops.impl.OpId.+,2,3,singleton.ops.NP]
  funcType= trait +
  opResult= CalcLit(Int,5)
res0: singleton.ops.impl.Rig.Add[singleton.ops.impl.Rig[2],singleton.ops.impl.Rig[3]] = singleton.ops.impl.Rig$Add$$anon$3@6fc0a38a

scala> res0.value
res1: res0.Out = Rig(5)

scala> implicitly[OpIntercept[OpId.+, Rig[2], Rig[3], 0]]
usingFuncName: opTpe= singleton.ops.impl.OpMacro[singleton.ops.impl.OpId.+,2,3,singleton.ops.NP]
  funcType= trait +
  opResult= CalcLit(Int,5)
res2: singleton.ops.impl.OpIntercept[singleton.ops.impl.OpId.+,singleton.ops.impl.Rig[2],singleton.ops.impl.Rig[3],0] = singleton.ops.impl.Rig$$anon$2@3320bafa

scala> res2.value
res3: res2.Out = Rig(5)

scala> implicitly[Rig[2] + Rig[3]]
usingFuncName: opTpe= singleton.ops.impl.OpMacro[singleton.ops.impl.OpId.+,2,3,singleton.ops.NP]
  funcType= trait +
  opResult= CalcLit(Int,5)


itree= singleton.ops.impl.OpIntercept[singleton.ops.impl.OpId.+,singleton.ops.impl.Rig[2],singleton.ops.impl.Rig[3],Int(0)]


usingFuncName: opTpe= singleton.ops.impl.OpMacro[singleton.ops.impl.OpId.+,singleton.ops.impl.Rig[2],singleton.ops.impl.Rig[3],singleton.ops.NP]
  funcType= trait +
  opResult= CalcUnknown(singleton.ops.impl.OpIntercept[singleton.ops.impl.OpId.+,singleton.ops.impl.Rig[2],singleton.ops.impl.Rig[3],Int(0)],Some(scala.Predef.implicitly[singleton.ops.impl.OpIntercept[singleton.ops.impl.OpId.+,singleton.ops.impl.Rig[2],singleton.ops.impl.Rig[3],Int(0)]](singleton.ops.impl.Rig.rigAddition[singleton.ops.impl.Rig[2], singleton.ops.impl.Rig[3], singleton.ops.impl.Rig[this.Out]](Rig.this.Add.addRig[2, 3, this.Out](impl.this.OpInt.impl[2 + 3]({
  final class $anon extends AnyRef with singleton.ops.impl.OpMacro[singleton.ops.impl.OpId.+,2,3,singleton.ops.NP] {
    def <init>(): <$anon: singleton.ops.impl.OpMacro[singleton.ops.impl.OpId.+,2,3,singleton.ops.NP]> = {
      $anon.super.<init>();
      ()
    };
    type OutWide = Int;
    type Out = Int(5);
    type OutInt = Int(5);
    final private[this] val value: Int(5) = 5;
    final <stable> <accessor> def value: Int(5) = $anon.this.value;
    final private[this] val isLiteral: Boolean(true) = true;
    final <stable> <accessor> def isLiteral: Boolean(true) = $anon.this.isLiteral;
    final private[this] val valueWide: Int = 5;
    final <stable> <accessor> def valueWide: Int = $anon.this.valueWide
  };
  new $anon()
}))))))


stack trace:
  singleton.ops.impl.GeneralMacros.abort(GeneralMacros.scala:658)
  singleton.ops.impl.GeneralMacros.abort$(GeneralMacros.scala:657)
  singleton.ops.impl.OpMacro$Macro.abort(OpMacros.scala:92)
  singleton.ops.impl.GeneralMacros.extractionFailed(GeneralMacros.scala:757)
  singleton.ops.impl.GeneralMacros.extractionFailed$(GeneralMacros.scala:755)
  singleton.ops.impl.OpMacro$Macro.extractionFailed(OpMacros.scala:92)
  singleton.ops.impl.GeneralMacros$MaterializeOpAuxGen.usingFuncName(GeneralMacros.scala:1405)
  singleton.ops.impl.OpMacro$Macro.impl(OpMacros.scala:99)


                 ^
       error: Cannot extract value from singleton.ops.impl.OpMacro[singleton.ops.impl.OpId.+,singleton.ops.impl.Rig[2],singleton.ops.impl.Rig[3],singleton.ops.NP]
       showRaw==> TypeRef(ThisType(singleton.ops.impl), singleton.ops.impl.OpMacro, List(TypeRef(SingleType(ThisType(singleton.ops.impl), singleton.ops.impl.OpId), singleton.ops.impl.OpId.$plus, List()), TypeRef(ThisType(singleton.ops.impl), singleton.ops.impl.Rig, List(LiteralType(Constant(2)))), TypeRef(ThisType(singleton.ops.impl), singleton.ops.impl.Rig, List(LiteralType(Constant(3)))), TypeRef(SingleType(SingleType(SingleType(ThisType(<root>), singleton), singleton.ops), singleton.ops.package), TypeName("NP"), List())))

[soronpo]

OK, I know the reason. Indeed, as you suspected the usingFuncName is failing since it's receiving a CalcUnknown and in not of a special case it's designed to handle. I propose that you:

1. Add a CalcOpIntercept here:
   

   singleton-ops/src/main/scala/singleton/ops/impl/GeneralMacros.scala

   Line 264 in 21f939a

   case class CalcUnknown(tpe : Type, treeOption : Option[Tree]) extends Calc {

  case class CalcOpIntercept(tpe : Type, tree : Tree) extends Calc {
    override val primitive: Primitive = Primitive.Unknown(tpe, "OpIntercept")
  }

2. In your change under unsupported, return CalcOpIntercept instead of CalcUnkown.
3. Add another special case handling in usingFuncName.
4. You should comb the code for where CalcUnknown is currently used and see if another case for CalcOpIntercept should be added (or maybe they should have common ancestry to be handled together).

[erikerlandson]

Thanks, I'll look into that. I think I may also be loading CalcUnknown with the wrong type and tree from the call to implicitly

[erikerlandson]

I think I may also be loading CalcUnknown with the wrong type and tree from the call to implicitly

Yeah, IIUC, I think I should be loading something more like the implicitly[...].Out into the type and possibly None for the value tree.

On a related note, subclassing OpIntercept under OpMacro forces me to compute a value for my custom types (e.g. Fraction), which feels dubious to me because (1) there may not be a corresponding value for the desired type output in the case of non-literal types, and (2) even if I do augment implicit details to create such a value, actually accessing that value inside of GeneralMacros is edging back into c.eval instead of just c.typecheck

[soronpo]

Yeah, IIUC, I think I should be loading something more like the implicitly[...].Out into the type and possibly None for the value tree.

Add support for OpIntercept symbol here:

singleton-ops/src/main/scala/singleton/ops/impl/GeneralMacros.scala

Line 458 in 21f939a

case TypeRef(_, sym, ft :: tp :: _) if sym == opMacroSym && ft.typeSymbol == funcTypes.GetType =>

This will allow to get the Out.
I think it's possible to generalize it properly by checking if its a subtype/subclass.

On a related note, subclassing OpIntercept under OpMacro forces me to compute a value for my custom types (e.g. Fraction), which feels dubious to me because (1) there may not be a corresponding value for the desired type output in the case of non-literal types, and (2) even if I do augment implicit details to create such a value, actually accessing that value inside of GeneralMacros is edging back into c.eval instead of just c.typecheck

I don't see how is this related to c.eval.

[soronpo]

You know what, leave it to me, I'll try to do this over the weekend, and you can finish the fraction on top.

[erikerlandson]

I'll try to do this over the weekend, and you can finish the fraction on top.

OK, thanks!

[erikerlandson]

@soronpo did you have a chance to play with this at all?

[soronpo]

@soronpo did you have a chance to play with this at all?

Sorry, still have too much on my plate. I'll get there soon though.

[soronpo]

Starting to work on it

[erikerlandson]

closing this in favor of #149