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Re: Unspecified?
From: |
Ludovic Courtès |
Subject: |
Re: Unspecified? |
Date: |
Fri, 14 Nov 2008 22:20:35 +0100 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.3 (gnu/linux) |
Hello,
"Maciek Godek" <address@hidden> writes:
> As I ran into the problem, I quickly came with a workaround:
> (define unspecified (if #f #t))
> which allows to define the most basic predicates:
> (define (unspecified? x) (eq? x unspecified))
> (define (specified? x) (not (unspecified? x)))
>
> but I find it kinda surprising that these are not available
> by default in the system.
They are not documented because they are not... specified. :-)
Actually, Guile defines `*unspecified*' and also provides
`unspecified?', so all you need to define is `specified?'.
Thanks,
Ludo'.