Vim - yank into search register

Is there any easy/quick way to "yank" into vim's "last search" register ("/)?

From the vim documentation, it appears that the answer is no, but that it can be assigned via a "let" command:

It is writable with ":let", you can change it to have 'hlsearch' highlight
other matches without actually searching.  You can't yank or delete into this
register.

Ideally what I'd like to do is something like:

"/5yw

which would yank the next 5 words under the cursor & put them in the last search buffer

Alternatively, if there is a way to search for the contents of a named register, that would work too. In other words, if I could do:

"A5yw

and then search for what is in register A, that would work too.

The closest I can come is to yank into a named register & then copy that register into the last search register, e.g.

"A5yw
:let @/=@A

At the risk of making a long question longer, I want to state that it's not always 5 words I'd like to "yank & search" -- sometimes it's 17 characters, sometimes it's to the end of the line, etc... so a hard-coded macro doesn't give me the flexibility I'd want.

After pressing / to enter a search string, you can then use Ctrl-R and then type the letter representing the register that you want to use.

eg.

• First, "Ayw to yank a word into register A
• Then, / ^R A to put the contents of register A into the search string.

If you did not use any register to store the yanked text vim uses 0 register. You can search for that by typing Ctrl-R 0 after /.

A more complicated example. Say that you want to search in another buffer for the text inside quotes which is under the cursor right now:

• You can do that with yi" (yank inner quote)
• Go to the buffer where you want to search
• Type /Ctrl-R 0

I'm using following code for that:

vnoremap <silent>* <ESC>:call VisualSearch('/')<CR>/<CR>
vnoremap <silent># <ESC>:call VisualSearch('?')<CR>?<CR>

	function! VisualSearch(dirrection)
		let l:register=@@
		normal! gvy
		let l:search=escape(@@, '$.*/\[]')
		if a:dirrection=='/'
			execute 'normal! /'.l:search
		else
			execute 'normal! ?'.l:search
		endif
		let @/=l:search
		normal! gV
		let @@=l:register
	endfunction

Searching for a selection:

if you want to first yank a section of a line, then use "v" and move with cursors until you have marked what you want, then press y for yank and now the selection is in register 0

you can then type /Ctrl-R 0

So basically an extended version of the # and * commands, right? It sounds like you want to define a custom operator (a command that expects a motion). I've never actually done this, but I did find a plugin which looks like it might make it easier to do so. There are some examples provided.