Survey: what new bit of syntax would you like in base #RStats?

What should the following bits of syntax do?

* ===
* ++ And --
* +=
* //
* ?
* {{ }}
* [[[ ]]]
* <<==
* (?: X)

#RStats syntax hypothetical

mean?

This is the same as "?mean" i.e. you can put the "?" at the end of the function name to access the documentation for that function