Indentation for comments in ESS

I've been frustrated for a long time that sometimes comments in R inside Emacs with ESS get indented incorrectly. Turns out I was just using it wrong. From the ESS manual:

By default, comments beginning with ### are aligned to the beginning of the line. Comments beginning with ## are aligned to the current level of indentation for the block containing the comment. Finally, comments beginning with # are aligned to a column on the right (the 40th column by default, but this value is controlled by the variable comment-column) or just after the expression on the line containing the comment if it extends beyond the indentation column.

In other words,

                                        # end of line
## indentation level
### beginning of line
for (i in 1:100) {
                                        # end of line
  ## indentation level
### beginning of line
  print(i)
}

This work is licensed under CC BY-NC 4.0