Re: [boost] 3-state boolean type

From: Douglas Gregor (gregod_at_[hidden])
Date: 2002-08-02 08:43:46

On Friday 02 August 2002 12:01 am, Andrew J Bromage wrote:
> G'day all.
>
> On Thu, Aug 01, 2002 at 10:55:23PM -0400, Douglas Gregor wrote:
> > I see that the naming of 'indeterminate' might be an issue, then. I need
> > the tribool in the domain of static analysis, where the third value means
> > "I can't statically determine if this boolean value is true or false, so
> > the value is indeterminate at compile-time". I'm not overly attached to
> > the name 'indeterminate', and 'maybe' is a lot shorter...
>
> Well if it's static analysis that you're doing, perhaps a better name
> is "bottom".

Potentially, yes, but then one might expect "top" as well. At that point we 
might as well just create the boolean lattice instead of a simple 3-state 
boolean :)

> Now that I think about it, would there be any value in a lattice type?

I could see a use of a lattice concept (with, e.g., meet and join functions 
defined) and perhaps an adaptor to make a BGL graph into a lattice. I'm not 
sure how one would create a lattice type -- most useful lattices tend to be 
infinitely wide, infinitely tall, or both.

        Doug