This keeps getting asked, and is a very useful feature on which I rely in my own nim fork.
I wrote a PR a while back: <https://github.com/nim-lang/Nim/pull/9560> but it was closed without much of a debate. Maybe there is hope this PR can be re-opened so I can address whatever needs to be addressed to get it in; according to @araq in <https://forum.nim-lang.org/t/1817#37522>
