Hello, World! Am I the only one who finds this is...

# stdlib

[bod]

Hello, World!

Am I the only one who finds this is kind of missing?

fun <E> MutableCollection<E>.set(elements: Collection<E>) {
    clear()
    addAll(elements)
}

fun <E> MutableCollection<E>.set(vararg elements: E) = set(elements.asList())

[bod]

Similarly,

fun <K, V> MutableMap<K, V>.set(from: Map<K, V>) {
    clear()
    putAll(from)
}

fun <K, V> MutableMap<K, V>.set(vararg pairs: Pair<K, V>) {
    clear()
    putAll(pairs)
}

[Dominaezzz]

set is confusing name to me. Since it's used for other stuff. Like setting an element in a list or map.

[bod]

Maybe reset then? replaceAll would make sense, but that already exists on Map, with a different meaning

[ephemient]

depends on your use case… why not just use a var Collection<E>?

[ephemient]

if it's being shared among multiple classes… consider re-structuring it to designate a single owner for the mutability

[bod]

My use case is for APIs exposing val MutableCollections. Maybe it is not that common, but for instance the Android Gradle plugin does this for resourceConfigurations and manifestPlaceholders

[bod]

(maybe replaceBy or replaceAllBy would be a good name)

[ephemient]

ah, understandable in that case. I don't think there's a good name for it - set would match the Provider.set, but can be confused with MutableList.set(index, elem), replace is also about items…

[andries.fc]

Ideally Kotlin should have an assignment operator which can be overloaded, for example:

operator fun MutableSet<T>.assign(another:Collection<T>) {
  clear()
  addAll(another)
}

To be used as such:

val set = mutableSetOf(1, 2, 3)
set = setOf(12,13,16)

[ephemient]

that would make it all the more confusing in case of var _: MutableCollection<*> - operator overloading isn't the right answer here, IMO

[ephemient]

a better naming scheme could use the word "content" or "values" to make it clear what is being affected, e.g.

fun <T> MutableCollection<T>.setAllValues(values: Iterable<T>)
fun <T> MutableCollection<T>.setValues(vararg values: T)

[Dominaezzz]

Kotlin isn't C++ sadly.