Re: Patch: make eldoc indicate current argument

[Richard Stallman]

    I was aware of such things (optional parameters in brackets), but
    didn't figure out what to do with them:

        ;; FIXME: What to do with optional arguments, like in
        ;;        (defun NAME ARGLIST [DOCSTRING] BODY...) case?
        ;;        The problem is there is no robust way to determine if
        ;;        the current argument is indeed a docstring.

Doc strings are so important that eldoc may as well have special-case
code for them.