I'm talking about the need to import ``` class Map...

# advent-of-code

[CypherK]

I'm talking about the need to import

class MapWithDefault<K,V>(val map:Map<K,V>,val default:(K)->V): Map<K,V> by map{
    override fun get(key: K): V = map[key] ?: default(key)
}

class MutableMapWithDefault<K,V>(val map:MutableMap<K,V>,val default:(K)->V): MutableMap<K,V> by map{
    override fun get(key: K): V = map[key] ?: default(key)
}

/**override standard [Map.withDefault]*/
fun <K,V>Map<K,V>.withDefault(default:(K)->V) =  MapWithDefault(this,default)
fun <K,V>MutableMap<K,V>.withDefault(default:(K)->V) =  MutableMapWithDefault(this,default)

whenever I want to use a map with default.
Because

val m = mutableMapOf<Char,Int>().withDefault{0}
val foo =  m['f']

will result in foo == null, without the imports.
And I never understood why that should be the expected behaviour.