I also have this posted here (no reflection librar...

# reflect

[Alan B]

I also have this posted here (no reflection libraries over there, but it’s there for easier readability): https://pl.kotl.in/AP_pbezIA

/*
 I'm working on a function to copy values from one instance to another.  
 At the moment I don't care about nullability, or type mismatches for field values. 

 Two data classes. Copy Public's matching properties from Private into Public. 
*/

data class Private(val a: String, val b: String)
data class Public(val a: String)

// This next function works "fine" but it's obviously typed to the receiver and has zero reuse.
// Note: I have no idea what or why this receiver is what it is with the this@toPublic
 
fun Private.toPublic(): Public  {
  val constructor = Public::class.primaryConstructor ?: error("No primary constructor found")
  val propertiesByName = Private::class.memberProperties.associateBy { it.name }
  return constructor.callBy(constructor.parameters.associateWith { parameter ->
    when (parameter.name) {
      // Eventually plan on adding a map to the function
      // so properties can be mapped to unmatched names, or coerced to other types
	  // Note: I have no idea what or why this receiver is what it is with the this@toPublic
      else -> propertiesByName[parameter.name]?.get(this@toPublic) // <-- so confused with the receiver
    }
  })
}

val privateOne = Private(a = "A", b = "B")
val publicOne = privateOne.toPublic()

// publicOne now has its 'a' value copied from privateOne

/*
 Now imagine that function above but make it a reusable. This is now more pseudocode as it will not compile, 
 and it's just wrong because I'm dumb in this area. What is the receiver to be in such a case on that else line?
*/
inline fun <reified R> toPublic(input: Any, output: R & Any): R {
  val constructor = output::class.primaryConstructor ?: error("No primary constructor found?")
  val propertiesByName = input::class.memberProperties.associateBy { it.name }
   val result: R = constructor.callBy(constructor.parameters.associateWith { parameter ->
     when (parameter.name) {
      // I have absolutely no clue as to what the receiver is here 
      else -> propertiesByName[parameter.name]?.get(input) // <-- so confused with the receiver
    }
  })

  return result
}

// what I would like to do
fun Private.toPublic2() = toPublic(this, Public::class)

/*
 Again, my confusion is on the receivers.
 Thanks for your time.
*/

[Alan B]

This channel don’t receive any love. I’ll post a link in a different one. 🙂