Re: fortran-fill-paragraph fails

[Richard Stallman <rms@gnu.org>]

    Suppose commark is `C', we will have :
    (string-match "^C" (concat "\0" commark "a")) -> nil
    (string-match "C" (concat "\0" commark "a")) -> 1
    (string-match "^ ?C" (concat "\0" commark "a")) -> nil

Why are these results correct?  What is the overall explanation for
the job this code is trying to do?

I find I can't understand these comments

	      ;; `commark' is surrounded with arbitrary text (`\0' and `a')
	      ;;  to make sure it can be used as an optimization of
	      ;; `comment-start-skip' in the middle of a line.  For example,
	      ;; `commark' can't be used with the "@c" in TeXinfo (hence
	      ;; the `a') or with the "C" at BOL in Fortran (hence the `\0').

As far as I know, COMMARK (which is how it should be written) refers
to some text copied out of the buffer.  What does it mean to say
whether that that text "can't be used with the `@c' in Texinfo"?

Is there anyone that actually understands that comment
and could rewrite it more clearly?