Hi! :wave:
Does anyone want to review this PR I opened to fix the CI (it wasn't running the tests): com-lihaoyi/upickle#359 ?
Thanks!
Then we can trigger a release @htmldoug @objektwerks
upickle to extract my case classs schema. The visitor that uPickle provide is great. I would like to have a visitor on the type if you know what I mean:- I have user defined
case class Foo(..) - I want a JSON deserializer for that class. That's easy, I can just use
macroRW - I also want to codegen Foo into a Python class. For that, it would be nice if I could re-use any of uPickle's machinery to have a Visitor on the schema of Foo. That way I'll be able to generate the Python code string easily
@lihaoyi I've been going through your wonderful tutorial on Visitor pattern yet again. I want to modify it slightly to include a cache based early stop for recursive Data structure. Think of an ADT which is self referencing. With the pattern in the tutorial, there is no way for visitor to communicate back to dispatcher to stop going further.
So I came up with this approach, could you please comment on what you think about it:
trait Visitor[T] {
def visitPrimitive(tpe: Type): T
def visitOption(innerVisited: T): T
def visitArrayType(innerVisited: T): T
def visitMapType(keyVisited: T, valueVisited: T): T
def visitStructType(tpe: Type): StructVisitor[T]
def stopValue: Option[T] = None // If defined, we stop visiting and simply return this value
}
trait StructVisitor[T] {
def visitFieldKey(name: String): Visitor[T]
def visitFiledType(name: String, visitedValue: T): Unit
def done: T
def stopValue: Option[T] = None // If defined, we stop visiting and simply return this value
}This is a visitor to visit Type from scala.reflect
java.lang.IncompatibleClassChangeError: class ilsop.models.RiskDecompositionSearchResult$$anon$10$$anon$11 has interface upickle.core.Types$CaseR$CaseObjectContext as super class
1 reply
I was looking at one of the open bugs for com-lihaoyi/upickle#356 and think I'm struggling a bit to figure out exactly where my understanding is breaking down. I've never used macros before, so that might be part of it.
The way it appears to me that things are happening right now is that the Sum types for the enumeration are being derived correctly when we go to write the values, but the implicit classtag that is carried through is the classtag for the enumeration supertype.
package upickle
import scala.language.implicitConversions
import utest._
import upickle.default._
object EnumTests extends TestSuite {
enum SimpleEnum derives ReadWriter:
case A, B
val tests = Tests {
test("simple") {
test("enum write") {
val parsed = write(SimpleEnum.B)
val expected = """{"$type":"upickle.EnumTests.SimpleEnum.B"}"""
assert(parsed == expected)
}
}
}
}I added some printlns to the code temporarily, but see the line beggining with Instance Check
----------------------- Running Tests upickle.EnumTests -----------------------
>>>>> SUM READER TRAVERSING [upickle.EnumTests$SimpleEnum$@1b73be9f]
>>>>> PRODUCT READER []
>>>>> PRODUCT READER []
>>>>> SUM WRITER TRAVERSING [upickle.EnumTests$SimpleEnum$@1b73be9f]
CASE CLASS WRITER defaults[]
>>>>> PRODUCT WRITER FULL CLASS NAME: upickle.EnumTests.SimpleEnum.A
CASE CLASS WRITER defaults[]
>>>>> PRODUCT WRITER FULL CLASS NAME: upickle.EnumTests.SimpleEnum.B
Instance Check upickle.EnumTests.SimpleEnum.A [B <: upickle.EnumTests$SimpleEnum]: true
RETURNING (upickle.EnumTests.SimpleEnum.A,upickle.implicits.CaseClassWriterPiece$CaseClassWriter@42721fe) for input B
>>>>> PRODUCT WRITER []
>>>>> PRODUCT WRITER []
X upickle.EnumTests.simple.enum write 30ms
utest.AssertionError: parsed == expected
parsed: String = {"$type":"upickle.EnumTests.SimpleEnum.A"}
expected: String = {"$type":"upickle.EnumTests.SimpleEnum.B"}
utest.asserts.Asserts$.assertImpl(Asserts.scala:30)
upickle.EnumTests$.$init$$$anonfun$3$$anonfun$2$$anonfun$2(EnumTests.scala:13)
1 targets failed
upickle.jvm[3.0.2].test.test 1 tests failed:
upickle.EnumTests upickle.EnumTests.simple.enum writeInstance Check line comes from TaggedReader.Leaf.findWriter, which I've modified like this (just enough to get some debugging information):class Leaf[T](c: ClassTag[_], tag: String, r: CaseW[T]) extends TaggedWriter[T]{
def findWriter(v: Any) = {
val isInstance = c.runtimeClass.isInstance(v)
println(s"Instance Check $tag [$v <: ${c.runtimeClass.getName}]: ${isInstance}")
if (isInstance) (tag -> r)
else null
}
}Ah, a simpler answer. The macros are more specific than the classtag. So even though the macro is giving the correct type, the classtag that is implicitly carried is not specific to the enum instance
CLASS NAME: upickle.EnumTests.SimpleEnum.B Classtag: upickle.EnumTests$SimpleEnum
