Customise vim-surround for markdown link syntax

after/ftplugin/markdown.vim

@@ -1,6 +1,39 @@
+" Enable spelling except in Windows terminal vim.
 if !has("win32") || has("gui_running")
   setlocal spell
 endif
+
+" Max 80 chars wide.
 setlocal textwidth=80
-" Use tabwidth of 4 to be markdown complient
+" Use tabwidth of 4 to be markdown complient.
 setlocal tabstop=4 shiftwidth=4 softtabstop=4
+
+" Custom surround for markdown link syntax.
+" "ys{motion}[" makes link out of "word" -> "[word]()"
+autocmd FileType markdown let b:surround_91 = "[\r]()"
+" "ys{motion}]" makes link out of "url" -> "[](url)"
+autocmd FileType markdown let b:surround_93 = "[](\r)"
+
+finish " Experiment functionality (disabled). {{{
+
+nnoremap yh :<C-U>set opfunc=<SID>yh<CR>g@
+function! <SID>yh(type, ...)
+  let save_reg_h = getreg('h')
+  " Mark positions
+  let begin = getpos("'[")[1:2]
+  let end = getpos("']")[1:2]
+  " Append after the end mark.
+  call cursor(end)
+  call setreg('h', ']()')
+  normal "hp
+  " Prepend before the begin mark.
+  call cursor(begin)
+  call setreg('h', '[')
+  normal "hP
+  " Place cursor at final )
+  call cursor(end)
+  normal f)
+  call setreg('h', save_reg_h)
+endfunction
+
+" }}}