Implement star movement start visual search

Author: thalesmello

plugin/slash.vim

@@ -29,20 +29,60 @@ function! s:wrap(seq)
   return a:seq."\<plug>(slash-trailer)"
 endfunction
 
+function! s:set_repeated_move_type(seq)
+  " Vmaps work by replacing * and # with yank text then search the underlying
+  " word. We have to recognize these modes in order to override * and # keys
+  " in normal mode later, remapping then to n or N as desired.
+
+  if mode() == 'v' && a:seq[0:1] ==# 'y/'
+    let b:slash_repeated_move = 'visual_forward'
+  elseif mode() == 'v' && a:seq[0:1] ==# 'y?'
+    let b:slash_repeated_move = 'visual_backward'
+  else
+    let b:slash_repeated_move = 'normal'
+  endif
+endfunction
+
+function! s:revert_search_direction(key)
+  if a:key ==# 'n'
+    return 'N'
+  elseif a:key ==# 'N'
+    return 'n'
+  elseif
+    return a:key
+  endif
+endfunction
+
+function! s:star_to_forward_backward(key)
+  if a:key ==# '*'
+    return 'n'
+  elseif a:key ==# '#'
+    return 'N'
+  else
+    return a:key
+  endif
+endfunction
+
 function! s:immobile(seq)
-  if exists('b:slash_repeated_move')
+  let repeated_move = get(b:, 'slash_repeated_move', '')
+
+  if repeated_move ==# 'normal'
     return a:seq
+  elseif repeated_move ==# 'visual_forward'
+    return s:star_to_forward_backward(a:seq)
+  elseif repeated_move ==# 'visual_backward'
+    return s:revert_search_direction(s:star_to_forward_backward(a:seq))
   endif
 
   let s:winline = winline()
-  let b:slash_repeated_move = 1
+  call s:set_repeated_move_type(a:seq)
   return a:seq."\<plug>(slash-prev)"
 endfunction
 
 function! s:trailer()
   augroup slash
     autocmd!
-    autocmd CursorMoved,CursorMovedI * set nohlsearch | unlet! b:slash_repeated_move | autocmd! slash
+    autocmd CursorMoved,CursorMovedI * set nohlsearch | let b:slash_repeated_move = '' | autocmd! slash
   augroup END
 
   let seq = foldclosed('.') != -1 ? 'zo' : ''