1 files changed, 51 insertions, 0 deletions
diff --git a/runtime/plugin/manpager.vim b/runtime/plugin/manpager.vim
new file mode 100644
index 0000000..076aca5
--- /dev/null
+++ b/runtime/plugin/manpager.vim
@@ -0,0 +1,51 @@
+" Vim plugin for using Vim as manpager.
+" Maintainer: Enno Nagel <ennonagel+vim@gmail.com>
+" Last Change: 2022 Oct 17
+
+if exists('g:loaded_manpager_plugin')
+  finish
+endif
+let g:loaded_manpager_plugin = 1
+
+" Set up the current buffer (likely read from stdin) as a manpage
+command MANPAGER call s:ManPager()
+
+function s:ManPager()
+  " global options, keep these to a minimum to avoid side effects
+  if &compatible
+    set nocompatible
+  endif
+  if exists('+viminfofile')
+    set viminfofile=NONE
+  endif
+  syntax on
+
+  " Make this an unlisted, readonly scratch buffer
+  setlocal buftype=nofile noswapfile bufhidden=hide nobuflisted readonly
+
+  " Ensure text width matches window width
+  setlocal foldcolumn& nofoldenable nonumber norelativenumber
+
+  " In case Vim was invoked with -M
+  setlocal modifiable
+
+  " Emulate 'col -b'
+  exe 'silent! keepj keepp %s/\v(.)\b\ze\1?//e' .. (&gdefault ? '' : 'g')
+
+  " Remove ansi sequences
+  exe 'silent! keepj keepp %s/\v\e\[%(%(\d;)?\d{1,2})?[mK]//e' .. (&gdefault ? '' : 'g')
+
+  " Remove empty lines above the header
+  call cursor(1, 1)
+  let n = search(".*(.*)", "c")
+  if n > 1
+    exe "1," . n-1 . "d"
+  endif
+
+  " Finished preprocessing the buffer, prevent any further modifications
+  setlocal nomodified nomodifiable
+
+  " Set filetype to man even if ftplugin is disabled
+  setlocal filetype=man
+  runtime ftplugin/man.vim
+endfunction