Hey, generic wizards. I have another one for you. ...

# announcements

[andylamax]

Hey, generic wizards. I have another one for you.
Among these two, which one is the recommended one? and most importantly, why?

//case A
inline reified fun <T:Any?> T.doThing(name: String = T::class.simpleName ?: "") {}

or

//case B
inline reified fun <T:Any> T?.doThing(name: String = T::class.simpleName ?: "") {}

[streetsofboston]

Don't know.... depends on the implementation of the actual function. It depends whether you want the this extension receiver to be nullable or not (and <T : Any?> can be abbreviated to just <T>).

[Zach Klippenstein (he/him) [MOD]]

Assuming you moved reified to the correct place, I don’t think 1 would compile - KClass can only refer to non-nullable class types

[muliyul]

Example for a use case: CharSequence?.isNullOrEmpty()

val str: String? = null
if(str.isNullOrEmpty()) { ... }

// vs isEmpty

if(str?.isEmpty() == true) { ... }
// equals required for nullable booleans.

[Nir]

why not

inline fun <reified T:Any> T.doThing(name: String = T::class.simpleName ?: "") {}

[Nir]

actually. TBH, your function is a bit weird because it's not actually using the instance at all.

[Nir]

and you're already going the inline/reified route. So why not:

//case D
inline fun <reified T:Any> doThing(name: String = T::class.simpleName ?: "") {
    println(name)
}

[Nir]

so you don't need to have an instance to call it at all