vim script: how to change “put =” to an append?

Question

I'm trying to hack the c-vim plugin because I don't like the way it inserts comments. I want this:

/* comment */

but it gives me this:

/* comment
 */

I'm sure it has its reasons, but I don't like it. So I'm digging through the c.vim file and I've found this:

function! C_CodeComment( mode, style )
   if a:mode=="a"
     if a:style == 'yes'
       silent exe ":s#^#/\* #"
       silent put = ' */'
     else
       silent exe ":s#^#//#"
     endif
   endif
   if a:mode=="v"
     if a:style == 'yes'
       silent exe ":'<,'>s/^/ \* /"
       silent exe ":'< s'^ '\/'"
       silent exe ":'>"
       silent put = ' */'
     else
       silent exe ":'<,'>s#^#//#"
     endif
   endif
 endfunction

I have not been able to find any documentation on the put = statement, which I'm pretty sure is the one I have to change in order to get vim to append */ to the last line of the comment. Can anyone point me in the right direction, please?

Answer 1

The function C_CodeComment is not defined in any of the files that come with recent versions of Vim. I searched a bit and it looks like you are using Fritz Mehner’s C/C++ plugin. It provides a C/C++ > Comments > code -> comment /* */ menu item (and a \c* mapping¹) that uses C_CodeComment.

The command put = ' */' appends a new line (see :help :put) that contains the contents of the special register =, which just evaluates whatever comes after it as a Vim expression. The particular expression used here is just a simple three character string (space, asterisk, forward-slash).

You can arrange for */ to be at the end of the last line² by adding a line like

silent normal kJ^

after the silent put = ' */' lines. It moves up to last commented line (k), joins it with the */ line (J), and then moves the cursor to first non-blank character of the line (^); the \co mapping¹ itself includes a j to move the cursor to next line after the newly commented region.

However, doing this will break the assumptions of the C_RemoveCComment function (which is used by the C_CommentCode “inverse” function): it expects to find and process */ at the beginning of the line (after optional whitespace).
If you never use the C/C++ > Comments > comment -> code menu item or the \co mapping¹, then you may be able to live without the ability to use this plugin’s uncomment feature.

---

¹ The \ “leader” of the mappings might be different if you have redefined localmapleader.
² This (in my opinion) makes for odd looking multiline comments (i.e. selecting more than one line via GUI selection or visual mode before invoking the commenting functionality):

With the middle two lines selected,

    foo();
    bar();
    baz();
    quux();

becomes

    foo();
/*     bar();
 *     baz(); */
    quux();

which seems like an odd style (typically, if * leaders are used on intervening lines, then the asterisks from the /* opener, the * leaders, and the */ ender are put in the same column).