A modern programming language that makes developers happier.

kotlinlang

Some sort of no-op comparator would be nice for starting a comparator chain. `compareBy` requires to much type info up front, at least the overload that takes a selector.

Interesting. Could you show how you'd stack comparators on top of the proposed comparator vs. how you do it now with `compareBy`?

Given I have a `List&lt;Pair&lt;String, String?&gt;&gt;` Right now I have to do this.
```val currentComparator = compareBy&lt;Pair&lt;String, String?&gt;, String?&gt;(nullsLast()) { it.second }
    .thenBy { it.first }```


If stdlib had something like this.
```object NoopComparator : Comparator&lt;Nothing&gt; {
    override fun compare(p0: Nothing?, p1: Nothing?): Int {
        return 0
    }
}

fun &lt;T&gt; noop(): Comparator&lt;T&gt; {
    return NoopComparator as Comparator&lt;T&gt;
}```

Then I could do this.
```val idealComparator = noop&lt;Pair&lt;String, String?&gt;&gt;()
    .thenBy(nullsLast()) { it.second }
    .thenBy { it.first }```

A workaround I guess is this but it's distracting in code reviews.
```val alternativeComparator = compareBy&lt;Pair&lt;String, String?&gt;&gt; {""}
    .thenBy(nullsLast()) { it.second }
    .thenBy { it.first }```

I can't quite justify adding `NoopComparator` to my codebase when I could just add another type param. But I guess that's besides the point now.

```compareBy(nullsLast()) { it: Pair&lt;String, String?&gt; -&gt; it.second }
compareBy(nullsLast(), Pair&lt;String, String?&gt;::second)
```
still a bit wordy but less than your current?

Hmm, the first one is seems like what I'm looking for.