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Re: Why is booleanp defined this way?


From: Pascal J. Bourguignon
Subject: Re: Why is booleanp defined this way?
Date: Sat, 18 Apr 2015 02:43:27 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)

Emanuel Berg <embe8573@student.uu.se> writes:

> Barry Margolin <barmar@alum.mit.edu> writes:
>
>> (booleanp nil) => (nil t)
>> (booleanp t) => (t)
>> (booleanp something-else) => nil

And even if that was true, that would still be a valid implementation,
since both (nil t) and (t) are generalized booleans that are true! 

But it is probably better that (booleanp (booleanp object)) be true too.

-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk


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