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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'.





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