Scala macros is a facility for Scala—a general-purpose programming language—that permits compile-time metaprogramming against Scala syntax trees, from within the Scala language.
Questions tagged [scala-macros]
774 questions
0
votes
1 answer
Scala Macros: Method overloading
I have a converter function that creates a case class object from JSON, which is defined as follows:
object JSONConverter {
import language.experimental.macros
def modelFromJson[T <: Model](json: JsValue):T = macro modelFromJson_impl[T]
}
I'm…
Emre
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Macro access to members of object where macro is defined
Say I have a trait Foo that I instantiate with an initial value i
val foo = new Foo(6) // class Foo(i: Int)
and I later call a secondMethod that in turn calls myMacro
foo.secondMethod(7) // def secondMethod(j: Int) = macro myMacro
then, how can…
Marc Grue
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Scala macros and code generation
Given the simple example source I need to be able to create a copy constructor and implicit conversion method. Can somebody please advice how to achieve this with Scala 2.10 and new macros feature?
import java.util.UUID
object Sample {
case…
jdevelop
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1 answer
enhanced assert scala macro
I’ve come across some annoying problems when using asserts where there is either
no good information available: why did it fails, and what the assert was about
the assert information is buried under a sea of unneeded information like too many…
Eric Mariacher
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2 answers
Universal copy function as a Macro
I'd really like to use case classes' copy feature in my project, but unfortunately I also need inheritance, which doesn't work well with case classes. So, I'm wondering if it's possible to write a macro which will generate a method for creating…
Lukasz Gieron
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0 answers
How can I recursively call a function from with a Scala 3 macro Expr?
I have a macro impl in which I have a function I want to call recursively for nested behavior. I've simplified a trivial count-down example to show the desired effect:
import scala.quoted.*
import quoted.Quotes
// Desired recursive effect:
//
// …
Greg
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1 answer
Get sequence of types from HList in macro
Context: I'm trying to write a macro that is statically aware of an non-fixed number of types. I'm trying to pass these types as a single type parameter using an HList. It would be called as m[ConcreteType1 :: ConcreteType2 :: ... :: HNil](). The…
gandaliter
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2 answers
Macros support in tooling
https://www.reddit.com/r/Kotlin/comments/7hoytl/kotlin_team_ama_ask_us_anything/dqt56nv/
Traditional macros are very hard to support well in the tooling
In Java we already have Lombok @Data what generate methods, almost the same as…
Axel
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scala rename case class property dynamically
I have an object
object Helper{
val fieldName = "fooBar
}
which provides the name for a field.
And a case class
case class BarBaz(fieldOne:Int, fieldTwo:String)
But instead of fieldTwo, I would like to refer to Helper.fieldname for the parameter…
Georg Heiler
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