convertTo

convertTo<Schema>(excessiveColumns = ExcessiveColumns.Keep)

class MyType(val value: Int)

@DataSchema
class MySchema(val a: MyType, val b: MyType, val c: Int)

val df = dataFrameOf("a", "b")(1, "2")
df.convertTo<MySchema> {
    convert<Int>().with { MyType(it) } // converts `a` from Int to MyType
    parser { MyType(it.toInt()) } // converts `b` from String to MyType
    fill { c }.with { a.value + b.value } // computes missing column `c`
}