I imagine this is asked a lot, but when are each of the following more appropriate:

val isFoo: Boolean get() = //foo things

fun isFoo(): Boolean = //foo things

Does the

get

imply inexpensive and static? Does the

fun

imply expensive and dynamic? I prefer to have functions only be verbs. So in practice i'll write the above always with getters, but I wonder if that's confusing or abusive. It could lead someone to constantly grab a property that has to be computed each time, e.g.

class Matrix(private val data: List<Vector>) {
    val rows get() = data
    val cols get() = List(numCols) { j -> Vector(List(numRows) { i -> data[j][i] }) }
}

Wouldn't this imply that

fun foo() {
    for (row in rows) {
        // things
        rows.otherThings()
    }
}

would take the same time to compute as

fun bar() {
    for (col in cols) {
        // things
        cols.otherThings()
    }
}