How to use a variable from register in command mode?

Question

I have a list of cities

London
Madrid
Paris
Brasil

I want to write a macro, that will add a ul tag and wrap each city in to an li.

I think, i need to create a variable like:

let i = 4

Than to write macro a(also have macros b, that will wrap each line into li)

qa(call var i)Vc<ul>j</ul>kp(call var i)@b

Answer 1

Doesn't answer the title question, but with https://github.com/tpope/vim-surround, I would do (type literally; angle brackets here are not key notation)

ysip<ul>Vitoj:normal yss<li>

and press Enter.

Answer 2

I am not sure why you think you need a variable, here.

Assuming the first macro, stored into register b, looks something like:

:let @b = "^C<li>^R"</li>"

Then the second macro, stored in register b, could look like this:

:let @a = "c<ul>^M</ul>^[P:.,']norm @b^M"

with ^M being produced with <C-v><CR>, ^R produced with <C-v><C-r>, and ^[ produced with <C-v><Esc>.

This should let you visually select the lines, say with vip, and do @a:

@b does the following:

1. move the cursor to the first printable character of the line with ^,
2. change the rest of the line with C,
3. insert <li>,
4. insert the content of the unnamed register with <C-r>",
5. insert </li>.

@a does the following:

1. change the currently selected text with c,
2. insert <ul>, followed by a carriage return, followed by </ul>,
3. leaves insert mode with <Esc>,
4. put the lines cut at step 1 above the current line with P,
5. execute @b on the lines we just changed with :.,']norm @b<CR>.

:help '] is the last line of the last change. Since the last change left you on its first line, you can create a range that covers all the lines in the last change and execute the desired macro on all those lines without having to count them.