vim-bracketed-paste/plugin/bracketed-paste.vim

" Code from:
" http://stackoverflow.com/questions/5585129/pasting-code-into-terminal-window-into-vim-on-mac-os-x
" then https://coderwall.com/p/if9mda
" and then https://github.com/aaronjensen/vimfiles/blob/59a7019b1f2d08c70c28a41ef4e2612470ea0549/plugin/terminaltweaks.vim
" to fix the escape time problem with insert mode.
"
" Docs on bracketed paste mode:
" http://www.xfree86.org/current/ctlseqs.html
" Docs on mapping fast escape codes in vim
" http://vim.wikia.com/wiki/Mapping_fast_keycodes_in_terminal_Vim

if !exists("g:bracketed_paste_tmux_wrap")
  let g:bracketed_paste_tmux_wrap = 1
endif

function! WrapForTmux(s)
  if !g:bracketed_paste_tmux_wrap || !exists('$TMUX') || system('tmux -V')[5] >= '2'
    return a:s
  endif

  let tmux_start = "\<Esc>Ptmux;"
  let tmux_end = "\<Esc>\\"

  return tmux_start . substitute(a:s, "\<Esc>", "\<Esc>\<Esc>", 'g') . tmux_end
endfunction

let &t_ti .= WrapForTmux("\<Esc>[?2004h")
let &t_te .= WrapForTmux("\<Esc>[?2004l")

function! XTermPasteBegin(ret)
  set pastetoggle=<f29>
  set paste
  return a:ret
endfunction

execute "set <f28>=\<Esc>[200~"
execute "set <f29>=\<Esc>[201~"
map <expr> <f28> XTermPasteBegin("i")
imap <expr> <f28> XTermPasteBegin("")
vmap <expr> <f28> XTermPasteBegin("c")
cmap <f28> <nop>
cmap <f29> <nop>