I'm trying to serialize a tree of expressions that...

# serialization

[Sam]

I'm trying to serialize a tree of expressions that must match a format that will be sent to an api. The expressions are a set of sealed classes that may or may not contain other expression classes. For instance the root is always an expression class that contains a list of other expression object as one of it's properties. Each node in the tree has it's own discriminator property called type. Right now I don't need to deserialize this json but I may need to in the future. The important part is that my output match the api. An example looks like:

{
  "type": "V",
  "expressions": [
    {
      "type": "M",
      "expr": "5+6"
    }
  ],
  "resultType": "success"
}

I started to go down the route of using the polymorphic serializer but I didn't know how to customize the type output. Should I write my own custom serializer for this type? If so is there a good example of how to do this?

[Dominaezzz]

You don't need a custom serializer.

[Dominaezzz]

Just annotate the parent class with @Serializer(PolymorphicSerializer::class).

[Dominaezzz]

Then the children with @SerialName("M") or @SerialName("V").

[Dominaezzz]

https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/polymorphism.md

[Sam]

That worked out perfectly. Thank you for the help.