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object ToFromMap { | |
implicit def materialize[T]: ToFromMap[T] = macro impl[T] | |
def impl[T: c.WeakTypeTag](c: Context): c.Expr[ToFromMap[T]] = { | |
import c.universe._ | |
val wt = weakTypeOf[T] | |
// Gets the type parameters, eg Holder[T, J] => List(T, J) | |
val baseTypes = wt.baseClasses.head.asType.typeParams.map{ _.asType.toType } | |
// Gives a Map(T -> Int, J -> Double) if we are extracting Holder[Int, Double] | |
val myTypes = baseTypes zip wt.typeArgs toMap; | |
println(myTypes) | |
def replace(t: Type) = t.map{ | |
case t if myTypes.contains(t) => myTypes(t) | |
case t => t | |
} | |
val (getters, setters) = wt.decls.collect{ | |
case m: MethodSymbol if m.isCaseAccessor => | |
val name = m.name | |
val t = m.returnType | |
val encName = m.name.encodedName.toString | |
println("Orig: " + t.typeArgs) | |
val recursed = replace(t) | |
println("New: " + recursed) | |
q"$encName -> t.$m" -> q"$name = map($encName).asInstanceOf[$recursed]" | |
}.unzip | |
c.Expr[ToFromMap[T]]{ | |
q"""new ToFromMap[$wt] { | |
def toMap(t: $wt) = Map(..$getters) | |
def fromMap(map: Map[String, Any]) = new $wt(..$setters) | |
}""" | |
} | |
} | |
} |
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