Combining @Stefan_Salewski 's and @jibal 's posts, here's an implementation with `setValue` renamed to the operator `[]=`. ;-)
<https://play.nim-lang.org/#ix=2vzb> A downside is that you can't use `MyTable` where a "plain" `tables.Table` can be used as an argument. At first sight, you could use something like <https://play.nim-lang.org/#ix=2vzg> , but that's leads to an infinite recursion. So I was wondering if it's possible to delegate to the "original" `[]=` for `tables.Table` somehow. Ok, this seems to work. :-) <https://play.nim-lang.org/#ix=2vzi>
