3

When saving a session with :mksession and :sourceing it back, the content of [No Name] unnamed buffers is lost.

I like to sometimes write temporary throwaway code or notes on a unnamed or scratch buffer, for the length of my session.

Just like Sublime Text saves the content of "untitled new tabs" when quitting and reopening it, is there a way/workaround/hack/plugin to save the state of unnamed buffers in Vim?

  • 1
    You want to save 'temporary throwaway code'. I'm confused. – Antony Jun 17 '16 at 2:48
5

You could use the following function. It is extremely hacky and I haven't tested it plenty but it seems to work.

The idea is to create a command :Mksession which will work like the original :mksession but will also save the unnamed buffers.

(Note that I had some inspiration from this answer

To do so it will call a function which does the following:

  • First handle the argument so that you can call the command with of without a filename as argument
  • Execute the original :mksession
  • Use a list which will contain the content of the unnamed buffer
  • Use a command which will test the name of each buffers. When the name is empty, getline() is used to add the content of the buffer to the list of contents.
  • Finally for each set of line, instructions are added to the session file to create a new buffer and put the content into it.

Add theses lines to your .vimrc:

function! MkSession(...)
    " Handle the argument
    if empty(a:000)
        let filename = "Session.vim"
    else
        let filename = fnameescape(a:1)
    endif

    " Create the session file according to the argument passed
    execute 'mksession! ' . filename

    " The list containing the lines on the unnmaed buffers
    let noname_buffers = []

    " Get the lines of all the unnamed buffers in the list
    execute "silent! bufdo \| if expand('%')=='' \| call add(noname_buffers, getline(1, '$')) \| endif"

    " For each set of lines
    " Add into the session file a line creating an empty buffer
    " and a line adding its content
    for lines in noname_buffers
        call system('echo "enew" >> '.filename)
        call system('echo "call append(0, [\"'. join(lines, '\",\"') .'\"])" >>'. filename)
    endfor

endfunction

command! -nargs=? Mksession call MkSession(<f-args>)

You can then simply call the command like that:

:Mksession

Or with a file name

:Mksession mysession.vim

Edit

As @DJ McMayhem pointed it out in the comments you can even add this line to your .vimrc:

cnoremap mksession Mksession

This would make ̀ :mksession(without capitalizedm) behave like the:Mksessioncommand we just defined (with capitalizedM`).

I mentioned it because for some user it could be seen as an advantage. However I would not recommend to use it: it hides the fact that you're using a custom function and if a side-effect appears it could add some difficulty to debug a problem.

  • I don't understand what you mean: the command you show makes Mksession (with capitalized M) call the builtin mksession which doesn't save the unnamed buffer. I'm probably missing your point. – statox Jun 17 '16 at 19:11
  • I might be wrong (I don't have a computer with me right now) but I think that when you define a user command the first letter has to be capitalized. (to avoid confusion with built in commands). I even think that you have to use a plug-in to create user-defined commands which are not capitalized. (but once again I can't test it right now so I'm not 100% sure) – statox Jun 17 '16 at 19:20
  • Alright, let's try this one more time. You could do :cnoremap mksession Mksession That's what I meant to say. – DJMcMayhem Jun 17 '16 at 19:22
  • Now I agree with you! :-) That's indeed a possibility. Im not sure that it's really a good idea because I might be good to remember that you're not using the built in feature (and thus might expect some side effects) but if one is really annoyed by the capitalized M it is possible to do that. Thanks for your suggestions! – statox Jun 17 '16 at 19:26
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    Thanks for this amazing answer! I tried to adapt the code to make it remember unnamed buffer/tab positions so that loading the session would look exactly the same as when Vim was exited, but this was too tedious. I finally switched to a more dedicated advanced session management tool (tmux) – Jerome Dalbert Jun 21 '16 at 21:56
2

Vim workarounds:

  • write temporary notes/code in predefined system-wide or project-wide files (possibly with the help of some custom functions/mappings)
  • use a Vim note-taking plugin

In both cases notes are saved in files, so when reopening your session their content will not be lost. When starting a new unit of work, just erase the previous content of the files (possibly with some automation).

External workaround:

Use a dedicated external session management tool, like tmux (which also does a lot of other stuff that one would not necessarily care about). I eventually chose this solution and am happy with it. Not only does it save the state of my Vim, but also the state of all my other console tabs/windows.

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