# Contextual extension methods
**URL:** https://discuss.kotlinlang.org/t/contextual-extension-methods/5666
**Category:** Language Design
**Created:** [December 4, 2017, 11:42am UTC](https://discuss.kotlinlang.org/t/contextual-extension-methods/5666 "2017-12-04T11:42:35Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@scurab](https://discuss.kotlinlang.org/u/scurab)
#### Post date: [December 4, 2017, 11:42am UTC](https://discuss.kotlinlang.org/t/contextual-extension-methods/5666/1 "2017-12-04T11:42:35Z")
Can I somehow define a “contextual” extension method as following example ?
For case `SomeClass` is final and not part of my source code ?
```auto
class SomeClass {
val value = true
fun Boolean.toInt() = if (this == true) 1 else 0
}
fun func() {
//true.toInt()//doesn't compile
SomeClass().apply {
value.toInt()//works fine
}
}
```
Any ideas how to do it ?
---
### Author:  [@yole](https://discuss.kotlinlang.org/u/yole)
#### Post date: [December 8, 2017, 10:26am UTC](https://discuss.kotlinlang.org/t/contextual-extension-methods/5666/2 "2017-12-08T10:26:23Z")
The `Boolean.toInt()` in your example becomes a member of `SomeClass`; it receives a `SomeClass` instance, can access its private members, etc. You cannot add a member to a class that is not part of your source code.
---
### Author:  [@scurab](https://discuss.kotlinlang.org/u/scurab)
#### Post date: [December 13, 2017, 9:42am UTC](https://discuss.kotlinlang.org/t/contextual-extension-methods/5666/3 "2017-12-13T09:42:59Z")
Hi Yole,
thank you for your reply. I think you missed my point. I understand that adding a member to some non-own class is not possible. But this is purely about extension methods
```auto
class SomeClass {
val value = true
fun Boolean.toInt() = if (this == true) 1 else 0
}
fun Boolean.toInt2() = if (this == true) 1 else 0
fun func() {
//true.toInt()//doesn't compile
SomeClass().apply {
value.toInt()//works fine
}
}
```
As you can see in this example. Extension function `toInt2()` is visible everywhere.
My point is to declare `toInt2()` somehow with same scope as `toInt()` has. So it would be accessible only in
`SomeClass().apply { ... }`
Thing is, for some extension functions they don’t make much sense in global scope as they are tied to some specific type in terms of usage/meaning. So i was wondering if I could declare extension function scoped only to some `someObject.apply {}`
I believe technically it should be feasible as it’s nothing else than static java method with argument of extended type. In this case it would have 2 arguments, one the extended type and 2nd the object what I’m trying to scope with…
Thanks for any thoughts…
---
### Author:  [@pdvrieze](https://discuss.kotlinlang.org/u/pdvrieze)
#### Post date: [December 13, 2017, 1:17pm UTC](https://discuss.kotlinlang.org/t/contextual-extension-methods/5666/4 "2017-12-13T13:17:40Z")
What you seem to want is the ability to have multiple receivers on a (extension) function. Currently this is not possible even though there appear to be (limited) use cases for it. Note that even the member extension functions can be quite awkward to use.