Kotlin also has extensions function `let` (and a couple of variants) which let you chain arbitrary methods:

``` val arr = ... val result = arr .let { column(it, "tags") .let { merge(it) } .let { unique(it) } .let { values(it) } ```

You add function references for single-argument functions too:

``` arr.let(::unique) // or (List<>::unique), depends on the function ```

all without adding a special language construct.