[boost] Re: 3-state boolean type

From: Daryle Walker (darylew_at_[hidden])
Date: 2002-08-15 02:01:15

on 8/11/02 3:27 PM, Dan'l Miller at optikos_at_[hidden] wrote:

> In reply to the various "what terms should we use for 3-valued and n-valued
> logic?" postings, a few of which are briefly quoted here:
[SNIP quoted postings]

> Boost should use existing terms for 3-valued and n-valued logic.
[SNIP origin of "Boolean" (George Boole) and his 3-value contemporaries]
> 
> It should be noted that there is not exactly one 3-valued logic. Lukasiewicz
> logic is defined for the following 3 values: 0=false,
> 1/2=indeterminacy/possibility, 1=true.  Other 3-valued logics are possible
> though (especially when considering the world of discrete n-valued logics as
> separate from Zadeh's fuzzy logic).  For example,
> 0=false, 1=indeterminacy/possibility, 2=true [logic in number systems of radix
> larger than 2, such as might be useful in optical computing with residue
> number systems]
[TRUNCATE more explanation]

A trial modulo-type class I put up a long time ago also had n-valued logic.
I put it in as an extra, just like "int" has arithmetic and bit-wise logic
operators.  Maybe that can serve some people's needs.  (I want to re-publish
it soon.)

-- 
Daryle Walker
Mac, Internet, and Video Game Junkie
darylew AT mac DOT com