Move lines with tildes to a certain section of a file

Question

I use vim to write my to-do list in markdown format.
To mark a certain task "done" I just make it strikethrough with two tildes(~).

Is there a way to automatically move all strikethrough text to a different section(#Things done, for example)?

And also is there a way to add a date to each task done?

Answer 1

Moving completed tasks

Presuming that a done line looks like this:

- ~A completed task~

Then you can do so with a :global command that performs a :move:

:g/^- \~.*\~$/m/^# Things done/+1
:g                                  # find lines that match
  /^- \~.*\~$/                      # the regular expression /^- \~.*\~$/
              m                     # and move them below
                               +1   # one line below
               /^# Things done/     # the line that matches /# Things done/

The regular expression:

/^- \~.*\~$/
 ^            # the start of the line
  -           # a markdown list item
    \~        # a tilde
      .*      # anything
        \~    # another tilde
          $   # the end of the line

You're probably not going to want to type this out every time, so why not make it into a mapping:

:nnoremap <leader>c :g/^- \~.*\~$/m/^# Things done/+1<CR>

Now you can move completed items just by pressing \c.

Appending the time

You can use a similar command to append the current date:

:g/^- \~.*\~$/call setline('.', getline('.') . ' ' . strftime('%x'))

This works very similarly, but instead of moving the lines, it appends the current date to them. (See :help strftime, :help getline, and :help setline.)

Doing both at once

If you don't want two separate mappings, you can wrap them in a function:

function CompleteTasks() abort
  g/^- \~.*\~$/m/^# Things done/+1
  g/^- \~.*\~$/call setline('.', getline('.') . ' ' . strftime('%c'))
endfunction

nnoremap <leader>c :call CompleteTasks()<CR>