How to diff the current text and the clipboard?

Question

How to create a diff of the current text and the clipboard?

It could result in a vertical split showing the clipboard content, and a normal diff between them. Opening a vertical split, pasting and diffing should work, but there are the commands :diffsplit and :diffthis, so I feel I may be missing something.

Answer 1

You could apply a variant of the Diff recipe:

function! DiffClipboard()
    let ft=&ft
    vertical new
    setlocal bufhidden=wipe buftype=nofile nobuflisted noswapfile
    :1put
    silent 0d_
    diffthis
    setlocal nomodifiable
    execute "set ft=" . ft
    wincmd p
    diffthis
endfunction
command! DiffClipboard call DiffClipboard()

• let ft=&ft store the file type of the source buffer in the ft variable
• vertical new create a new vertical window (aka split)
• setlocal bufhidden=wipe butype=nofile nobuflisted noswapfile make the underlying buffer of the new window a temporary buffer
• :1put paste the content of the default register after line 1 (if you want to use the * register replace with :1put *)
• slient 0d_ delete the first line of the buffer (the clipboard content starts on line 2)
• diffthis make the buffer part of the diff
• set local nomodifiable make the buffer non modifiable
• execute "set ft=" . ft align the buffer filetype with the source buffer filetype.
• wincmd p switch back to the source buffer
• diffthis make the source buffer part of the diff

Remark: the vertical buffer is created at the right side (if the splitright option is set) of the source buffer. I you want to switch the order you can add the wincmd r command after the vertical new command or unset the splitright option (:set nosplitright).