# Tipps & Tricks

###### tags: `TimoliaCreative` `TranClate` `Doucmentation`

## Kotlin features

### with-operator

The with operator can set a certain context.

Sample:

fun mainFunction() {
    addon {
        entity {
            name("mouse")
            behaviour {
                getMyMouseBeh(beh = this)
            }        
        }
    }
}

fun getMyMouseBeh(beh: AddonEntityBeh) {
    with(beh) {
        components {
            physics { }
        }
        componentGroups {
            componentGroup("sample") {
                
            }
        }
    }
}

In this case we can just call `components { }` as if we are still in the main body and don't have to call `beh.components{ }`.

### Context Receivers

A context receivers is still a pre-experimantal feature, see the jetbrains introduction video for mor information: [https://www.youtube.com/watch?v=GISPalIVdQY](https://www.youtube.com/watch?v=GISPalIVdQY).

### Iterating/Using Data

It might be useful to use maps, lists or other froms of storing data like coordinates. Here are some methods to iterate more elegant through these data structures.

val test = mapOf(
    1 to "1",
    2 to "2"
)
for ((key, value) in test) {    //this needs a iterator fun like maps or lists
    //do stuff
    if(key.toString() == value) {
        println("yay")
    }
}

this method is called destructering and can also be used outside of loobs:

val test = 1 to "1"    //this is a fancy way to declare a Pair

val (first, second) = test
//do stuff
if(first.toString() == second) {
    println("yay")
}

Note: It's generally considered bad practice to use destructering in lists but you may have a case for using it:

val test = listOf(1,2,3)

val(x,y,z) = test
//do stuff
val sum = x + y + z