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#f = #none ?
- To: alms@cambridge.apple.com
- Subject: #f = #none ?
- From: Stavros Macrakis <macrakis@osf.org>
- Date: Wed, 18 Nov 1992 15:42:09 -0500
- Cc: info-dylan@cambridge.apple.com
- In-reply-to: Andrew LM Shalit's message of Wed, 18 Nov 1992 11:23:07 -0500 <9211181613.AA07547@cambridge.apple.com>
- Sender: macrakis@osf.org
alms suggested:
> (bind ((no-value (cons #f #f)))
> (define-method true-false-dontcare (#key (arg no-value))
I replied:
>
> Small problem here: there is no way to explicitly specify a don't care
> value. Correction: make no-value visible.... Do you like that
> solution? I don't.
alms continued:
I don't see how you can have it both ways. Either the don't care value
is an explicit published part of the protocol, or it's not.
OK, so you export no-value as the no-value indicator. But it does not
respect Dylan semantics ("in Dylan, all objects besides #f count as
true", p. 63). I'd prefer to see #t represent True, #f represent
False, and anything else not be a boolean value at all. Similarly,
#nothing should mean nothing, and #f should mean something, namely
boolean false.