[I missed emacs-devel in my last email, sorry. Should use Gnus :-)]

On Mon, Apr 16, 2018 at 5:32 PM, Lars Ingebrigtsen <larsi@gnus.org> wrote:
>
> João Távora <joaotavora@gmail.com> writes:
>
> > Just a CL-style convenience (wouldn't your reasoning apply to
> > the second argument in general?). Perhaps, as an example,
> > you could clarify a bit better what exactly is passed to the third
> >  function in case the second property [i meant argument] is nil.
>
> The arguments to the predicate will be the same in any case -- the first
> argument is the VALUE (in this case nil) and the second is the text
> property value.
>
> It'll probably become a bit clearer after I've written
> the function and some documentation and added some examples.
> I'm typing away as we speak.  I mean mail.  :-)

OK. In your example tho, I think will need to distinguish the case where
the property's value is nil from the case where the property isn't set at
all.