Re: [boost] 3-state boolean type

From: Rene Rivera (grafik666_at_[hidden])
Date: 2002-08-04 23:20:30

[2002-08-05] Matthew Hurd wrote:

>In the GUI check box example it mean true_and_false.  Other times it may
>mean unknown rather than true_or_false, there is a subtle difference.
>
>matt.
>
>----- Original Message -----
>From: "Douglas Gregor" <gregod_at_[hidden]>
>To: <boost_at_[hidden]>
>Sent: Monday, August 05, 2002 12:03 PM
>Subject: Re: [boost] 3-state boolean type
>
>
>> On Sunday 04 August 2002 09:22 pm, Andrew J Bromage wrote:
>> > The problem is that while tribools have a well-understood calculus,
>> > they are suited to many varied interpretations.  Calling the third
>> > value "unknown", "undefined", "maybe", "bottom" or whatever sounds
>> > to me like calling your floating point type "length" or "probability".
>> >
>> > Unfortunately, I don't think there is a better name, so I'm not
>> > going to argue with whatever is chosen.
>> >
>> > Cheers,
>> > Andrew Bromage
>>
>> Here's my last potential suggestion: "true_or_false". Otherwise, I'm
going
>for
>> "unknown" :)
>>
>> Doug

Haven't followed this thread very closely, and I would certainly use the
type when available... but... why not just provide a small set of
names/aliases for the third state? IT would make most people happy this way
and it would seem reasonable given the context dependency of the type.

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