Create indented comment box vim

Question

Background

I have a code file and I like to place comments inside my code. Sometimes, these comments are boxed:

defmodule BananasModule do

    ##############
    # Public API #
    ##############

    def function_blabla do .....
end

Objective

My objective is to have a key sequence (a macro, for example) that surrounds the line I am at with a boxed comment. For example, given the following file:

defmodule BananasModule do


    <cursor> Public API

    def function_blabla do .....
end

After using some command, I would ideally get:

defmodule BananasModule do

    ##############
    # Public API #
    ##############

end

Do notice how the comment box is indented. This is very important.

What I have tried

I have tried out the NERDCommenter plugin, but unfortunately it doesn't have this feature.

I have also tried to create a macro following this discussion:

:let @a = "I## \<Esc>A ##\<Esc>yyPVr#jpVr#"

But the commend box I get after executing @a is not indented:

defmodule BananasModule do

####################
    ## Public API ##
####################

end

Problem

Although I feel like I came close, I don't know enough about macros and configurations to make my comment boxes indented.

Answer 1

Well, "put text into a box" is a well-known Vim excercise. I'm not sure where I saw it for the first time, but the most elegant solution, IMO, is to use :h v_r

So it becomes:

nnoremap <leader># I#<Space><Esc>A<Space>#<Esc>yy2P<C-V>$r#2j.

I#<Space><Esc> --- add "# " at the start of line

A<Space>#<Esc> --- add " #" at the end of line

yy2P --- make 2 copies of the current line (so we have three identical # text # lines)

<C-V>$r# --- change the top line into #####

2j. -- and the same for bottom line

Answer 2

This can be best accomplished with Ultisnips and vim-snippet.

vim-snippets provides a snippet box which can create a bounded box. It is just what you want. I have tested on a Python source file and it works great. Give it a try.

Answer 3

The LudoPinelli/comment-box.nvim neovim plugin seems to address this use-case.