Plugin config settings: Newline "\n" returns ^@ control character?

Question

I'm trying to configure the NERDCommenter plugin to handle multiline ruby comments (i.e., nested inside =begin and =end).

The relevant setting is something like this:

let g:NERDCustomDelimiters = {
    \ 'ruby': {'left': '# ', 'leftAlt': "=begin\n", 'rightAlt': "\n=end" }
    \ }

except this gives me the ^@ control character instead of an actual newline.

Found this in a primer on vimscript

Note that strings can be specified with either double-quotes or single-quotes as delimiters. Double-quoted strings honor special "escape sequences" such as "\n" (for newline), "\t" (for tab), "\u263A" (for Unicode smiley face), or "\" (for the escape character).

and made sure to place the strings inside double quotes. Still no dice. What gives?

Answer 1

^@, if you look at man ascii, is the ASCII NUL character. That makes me think this has to do with how newlines are inserted in the replacement string of a :substitute command. From :h :s%:

  <CR>        split line in two at this point
              (Type the <CR> as CTRL-V <Enter>)                  s<CR>
  \r          idem                                               s/\r
  \<CR>       insert a carriage-return (CTRL-M)
              (Type the <CR> as CTRL-V <Enter>)                  s/\<CR>
  \n          insert a <NL> (<NUL> in the file)
              (does NOT break the line)     

Since \n inserts a <NUL>, perhaps you should try \r=end.