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

{{ }} initiates a mode where whitespace is significant and R code can be formatted like python

{{
for (i in x)
s += I
cat("inside loop: ", s, "\n")

print("loop finished")
}}