Tag: scala-3

In this post, we will see how to resolve Int Refined Positive doesn’t compile Question: The followfing code doesn’t compile: The error is: I used Scala 3.2.2 and latest Refined eu.timepit::refined:0.10.2 According to documentation https://github.com/fthomas/refined it shoud compile. Best Answer: ...

In this post, we will see how to resolve Is there a simple Scala 3 example of how to use quoted.Type as replacement for TypeTag? Question: Martin Odersky said Scala 3 has the quoted package, with quoted.Expr as a representation ...

In this post, we will see how to resolve How to do type-level addition in Scala 3? Question: How can I impletement type-level operations (addition in this case) in Scala 3 ? Here is what I would like to do ...

In this post, we will see how to resolve Type negation in Scala 3 Question: Is it possible to implement fail proof Not[A] type in Scala 3? Here is a question asked some years ago: how-can-i-have-a-negation-type-in-scala. Unfortunately, a solution based ...

In this post, we will see how to resolve Spark: DF.as[Type] fails to compile Question: I’m trying to run an example from the Spark book Spark: The Definitive Guide build.sbt main.scala Getting an error with the line val flights = ...

In this post, we will see how to resolve scala3: Methods on enum case, possible? Question: I’m trying to define an ADT (tagged union type, actually). But the compiler complains… Is it possible to add methods specific cases of a ...

Question: I’d like to use Mirrors or some other technology to serialize ADTs. My concrete use case is that I’m serializing messages over a channel. I can model the messages with case classes; that’s easy enough. That gives me the ...

Question: I’m reading the MEAP of the second edition of “Functional Programming in Scala” and I ran across the following in a listing: In Parsers.scala: In Reference.scala we have: In JSON.scala (an implemetation of a JSON parser using the Parsers ...

Question: I am learning scala from docs.scala-lang.org. There is an example After compiling with scalac I run scala HelloYou Al and get java.lang.NullPointerException followed by at java.lang.reflect.Array.getLength(Native Method) at scala.collection.ArrayOps$.size$extension(ArrayOps.scala:197) at HelloYou$.<clinit>(HelloYou.scala:2) at HelloYou.main(HelloYou.scala) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) What’s wrong? It’s ...