Emailing (mutt) and vim advanced config

Here are some tips you might like for advanced emailing with vim. I use mutt as my email client, but these tips should be mostly applicable to any other email client you might use.

First, let's talk about format flowed text. Perhaps you believe so strongly in 72 character width emails that you tend to enforce this philosophy on everyone you email. If you are a more reasonable person, you prefer 72 characters for writing and in some circumstances reading, but certainly not while reading on a phone, for example. The solution to this is format flow text.

Essentially, any line that ends in white space is continued on the next line and any line that ends not on white space terminates a paragraph. Hence, email clients that respect format flow treat any newlines preceded by a space a soft return and any preceded by a non-space a hard return.

To use this in mutt and vim, we first have to turn on format flow in mutt so that it puts a flag in the email header.

# muttrc
set text_flowed

Now, we need to make sure that vim is on board. I now add the following to .vim/ftplugin/mail.vim

" ftplugin/mail.vim
setl tw=72
setl fo=aw

The first line sets the textwidth for the current buffer to be 72 characters. The second line turns on formatting options 'a' and 'w'. The 'a' option is not necessary, but it is nice. 'w' denotes that paragraphs are terminated by lines that end in non-white space. 'a' automatically reformats a paragraph so if you edit the interior of paragraph, vim will automatically apply the 72 character width across the whole paragraph. For slightly more, see :help fo-table.

Great, we now have format flow text working. We can write emails and the reader no longer has to read jagged edge emails on their phone! In fact, now that the emails are no longer so ugly, we might have email conversations with people! But now we have a new annoyance. In mutt (at least this is the case without setting edit_headers) what I observe is that on a reply, I am given a file to edit where the first line says "On Mon Dec, 29, Someone wrote:". That's pretty annoying. I'd like there to be a blank line between my new email and that line. Sure I can press "O" in vim and open a new line and then make sure I hit return twice, but if I'm going to do that every time, it should be automatic.

So I set up an autocmd to insert two blank lines at the top of the email if the email already contains content. First, let's write a function that does this and then call it in an autocmd. Here's the function:

" add two blank lines if already content
function IsReply()
    if line('$') > 1
        :1
        :put! =\"\n\n\"
        :1
    endif
endfunction

What this does is checks the line number of the last line, if it is greater than 1 (ie there already is content) it goes to the first line and pastes two returns and then returns to the first line.

Now, we call that function in an autocmd and our ftplugin/mail.vim file now looks like this:

" ftplugin/mail.vim
function IsReply()
    if line('$') > 1
        :1
        :put! =\"\n\n\"
        :1
    endif
endfunction

augroup mail_filetype
    autocmd!
    autocmd! VimEnter /tmp/mutt* :call IsReply()
augroup END

setl tw=72
setl fo=aw

This is pretty nice, but how should we handle the formatting of the quoted text from the reply? Surely, we'd like to apply format flow to that as well. Indeed, we can using the external program par which is a text formatter and adding some spaces at the ends of lines. If you have par installed, you can add to the IsReply() function:

function IsReply()
    if line('$') > 1
        :%!par w72q
        :%s/^.\+\ze\n\(>*$\)\@!/\0 /e
        :%s/^>*\zs\s\+$//e
        :1
        :put! =\"\n\n\"
        :1
    endif
endfunction

These three new lines do the following. First, they let par reformat the file (make sure you have par installed!). The argument w72q sets the width to 72 and supports quotes, meaning it will not make a mess of the '>' characters indicating quote level.

The next line :%s/^.\+\ze\n\(>*$\)\@!/\0 /e is a search and replace across the whole buffer. It searches for any lines that contains one or more characters followed by a line that is not 0 characters or only '>' characters. The actual matched bit is the original line. The substitution is that same line with a space at the end.

The next line :%s/^>*\zs\s\+$//e is another search and replace across the whole buffer. I suspect it is possible to combine these two search and replaces, but I haven't bothered to figure it out yet. What this one does it looks for any lines that are the '>' followed by whitespace. Such lines are replaced by just the string of '>'.

Thus, blank lines are not swallowed up by flowed text!

Ah, now writing email is so much nicer. It's not totally perfect, but it's pretty good. Another thing we can do is start in insert mode. Very rarely do I not want to immediately insert text when writing an email. Let's add that to the augroup. Also, before anything else, get rid of old signatures.

" ftplugin/mail.vim
function IsReply()
    if line('$') > 1
        :g/^>\s\=--\s\=$/,$ delete
        :%!par w72q
        :%s/^.\+\ze\n\(>*$\)\@!/\0 /e
        :%s/^>*\zs\s\+$//e
        :1
        :put! =\"\n\n\"
        :1
    endif
endfunction

augroup mail_filetype
    autocmd!
    autocmd VimEnter /tmp/mutt* :call IsReply()
    autocmd VimEnter /tmp/mutt* :exe 'startinsert'
augroup END

setl tw=72
setl fo=aw