Can a lambda store info like which property of a o...

# random

[kartikpatodi]

Can a lambda store info like which property of a object to use?
For example I have a have a class Person with id and name
Now I want to find the index of the person having id = 3 from a list of persons

val pos = persons.imdexOf{ it.id == 3 }

But i just want to create something like

persons.findPos(Person::id, 3)

How can i tell the compiler to use the id property?

[gildor]

Are you looking something like getter reference?

Person.id::get

[kartikpatodi]

Exactly @gildor

[kartikpatodi]

Can you share how it would look in Kotlin

[leolima]

Something like

fun <T, R> Iterable<T>.findPos(valueExtractor: (T) -> R, input: R): Int

?

[gildor]

@kartikpatodi As I understand just now you are looking rather something like this:
https://pl.kotl.in/ByNbMJrK4

[gildor]

example with getter (which I wrote in a wrong way) make sense if you need reference to getter of particular instance

val getter: () -> Int = Person(1)::id::get`

[kartikpatodi]

@gildor isn't this using reflection?

[kartikpatodi]

@leolima Thanks your solution worked

[gildor]

No, it doesn't require full reflections

[gildor]

But usage of lambda is actually more flexible

[gildor]

And still very similar
https://pl.kotl.in/BJxljJBtN

[gildor]

I just thought that property syntax was closer to your original example

[kartikpatodi]

Actually you can omit the get part and just use Person::id with the lambada approach

[gildor]

Ah, you right 👍