reduce condition nesting

[Adam D. Ruppe]

On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
> for instance in kotlin it can be replace with this:
>> when {
>>     c1 -> foo(),
>>     c2 -> bar(),
>>     c3 -> ...
>>     else -> someDefault()
>> }

The `switch` statement covers some of these cases too.