[asdf-devel] Question about use of :unspecific

[Faré]

On 15 March 2010 22:58, Robert Goldman <rpgoldman at sift.info> wrote:
> Isn't supplying :unspecific as the value of :type always to be avoided?
>
> The CLHS says:
>
> "Portable programs should not supply :unspecific for any component."
> [documentation for function MAKE-PATHNAME]
>
> and in section 19.2.2.2.3 :UNSPECIFIC as a component value
>
> "A conforming program must never unconditionally use a :unspecific as
> the value of a pathname  component because such a value is not
> guaranteed to be permissible in all implementations."
>
> So instead of supplying this for a couple of cases and then trying to
> avoid it for others, shouldn't we be avoiding it altogether?
>
> I confess that I don't fully understand this issue, since it seems like
> the CLHS makes it clear that NIL is /not/ fully equivalent to
> :unspecific (since the latter is not "overwritten" in a merge), and yet
> tells us not to use the latter....
>
> If anyone can clarify this, it would be great....
>

Oops. I hadn't paid attention to this paragraph.
Should we use :unspecific based on a whitelist of known-working
implementations, or should we just avoid it altogether?

[ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ]
Artificial intelligence is what we don't know how to do yet
        — Alan Kay