Scheme Digest #125

[Andre van Meulebrouck <vanMeule@allegheny.scrc.symbolics.com>]

    Date: Thu, 25 May 89 02:27:13 -0700
    From: "Jonathan S. Shapiro" <shap@polya.stanford.edu>

    Very well.  I hereby specify an object whose name is

	    #UNSPECIFIED

    Any association between this name and some meaning in your mind is
    coincidental.  I propose that all functions/forms that under some
    conditions currently return an unspecified value should now return a
    value which is EQ? to the value named by #UNSPECIFIED under those same
    conditions.

    Note that you are only in violation of R3RS if you *tell* me that that
    is what you do...

    Seriously: It's a non-damaging change, and there seems to be concensus
    that it is valuable to some part of the community and has no impact to
    speak of on anyone else.

    Let's do it.

    Jon

[Disclaimer:  my opinions are purely my own.]

An off-the-cuff comment after seeing the argument posed that way (^^) is:  "Why
not?  After all there is canonical truth!".

I see a lot of parallels between canonical unspecified and canonical truth.

I'm not taking sides however, because my jury's still out and/or I don't care
enough to get really religious one way or the other about it.

BTW:  I think the whole thing with nil vs. () vs. #f got a lot of mental energy
spent on it, and even after all that mind power being focused on that issue, I'm
still not convinced that things are now consistent or appreciably cleaner than
before:  the net outcome seems to have hypocrisies of its own such that I'm not
convinced Scheme is truly better off than Common Lisp (on the nil issue) for all
the hubbub and hoopla.