[at]optics

optics.java

/**
 * Java, because kotlin doesn't allow fields for annotations
 */
public @interface optics {

    Type[] value() default {};

    public enum Type {
        ISO, //data class
        LENS, //data class
        OPTIONAL, //data class
        PRISM //sealed class
    }

}

test.kt

//Generates prism
@optics sealed class NetworkResult {
    data class Success(val content: String) : NetworkResult()
    object Failure : NetworkResult()
}

//Error: Optional is not valid for sealed class
@optics(OPTIONAL) sealed class NetworkResult2 {
    data class Success(val content: String) : NetworkResult2()
    object Failure : NetworkResult2()
}

//Generates iso, lens and optional
@optics
data class Company(val name: String)

//Generates only iso
@optics(ISO)
data class Company2(val name: String)

//Error: Prism is not valid for data class
@optics(PRISM)
data class Company3(val name: String)