Indentation with "#." start of paragraph

Question

When I type 1. blah blah blah Vim recognizes the 1. prefix and it indents the rest of the paragraph tidy.

I would like to configure Vim to do the same thing with #. literal prefix, since ReST files autonumbers the paragraphs when started with #..

In this SO answer I got suggested this:

let &formatlistpat = '^\s*\%(\d\+\|#\)[\]:.)}\t ]\s*'

I added this to my .vimrc:

autocmd BufRead,BufNewFile *.rst let &formatlistpat = '^\s*\%(\d\+\|#\)[\]:.)}\t ]\s*'

It doesn't work. In fact, I modified the regexp and Vim seems to ignore anything I put there.

Answer 1

:help 'formatlistpat' says:

A pattern that is used to recognize a list header. This is used for the "n" flag in 'formatoptions'.

And :help 'formatoptions' says:

Vim default: "tcq"

:help fo-table describes the meaning of the n flag:

n        When formatting text, recognize numbered lists. This actually uses the 'formatlistpat' option, thus any kind of list can be used.
[..rest snipped..]

So I suspect it's probably a matter of just adding this flag to formatoptions. To add the flag, use:

set formatoptions+=n