In macro "@k", using ^M at end of "call function()" executes the function, but also undesirably adds a new line to my text

Question

I am running nVim v 0.10.1 on archlinux. Everything is up to date.

I am running this macro as defined in .vimrc:

let @k =  '\z:call CZC()'

But a carridge return is necesary to make this run, when I key @k so it becomes

let @k =  '\z:call CZC()^M'

This works but ^M executes two carridge returns

• one run's the call function, and
• one inserts a carridge return into my currently being edited text as a new line.

I only want one carridge return, that will execute @k not two. How can I add the carridge return at the end of the macro, to run the macro, without adding a new line to my text?

Answer 1

This happens because when you use :let @ to set a register, it detects whether the register should be made linewise based on whether the value ends in a <NL> or <CR>.

See this part of :help :let-@:

If the result of {expr1} ends in a <CR> or <NL>, the register will be linewise, otherwise it will be set to characterwise.

The ultimate side effect of making a register linewise is that a <NL> is appended at the end.

You can see that with the :reg k command:

:reg k
Type Name Content
  l  "k   \z:call CZC()^M^J

The ^J is the added <NL>.

One way around this is using setreg(), in which case you can explicitly set the register to be characterwise even though the contents end with <CR>:

call setreg('k', '\z:call CZC()^M', 'c')

Or, slightly better, using \r in a double quoted string, that way your file doesn't need to have special characters and is less likely to be corrupted:

call setreg('k', "\\z:call CZC()\r", 'c')

Answer 2

filbranden has done a great job of explaining what causes the issue.

An alternative to using his suggestion of using setreg() is to end your macro with a Ctrl-J instead of a CTRL-M. You can do this either by typing Ctrl-VCtrl-J to enter it literally^*, or with a string escape:

let @k =  "\\z:call CZC()\<C-J>"

You can then see with :reg k that this doesn't cause the :let command to add the additional character:

:reg k
Type Name Content
  l  "k   \z:call CZC()^J

The CTRL-J will still cause your command-line command to be executed, though, as desired.

_{*: Note that this will be notated as ^@ in the command-line. See :help NL-used-for-Nul.}