boolean true and false values.

[Greg Ewing]

Tim Rowe wrote:
> 
> > >what would you delimit it with? :-)
> >
> > {x,y,z} ?
> 
> That's going to get me confused...

Maybe that could be syntactic sugar for a dictionary which
maps the keys x, y and z to some default value, e.g. 1.
Then add some operators for doing set operations on
dictionaries of that form, and hey presto -- a set type
without adding a new type!

-- 
Greg Ewing, Computer Science Dept,
+--------------------------------------+
University of Canterbury,	   | A citizen of NewZealandCorp, a	  |
Christchurch, New Zealand	   | wholly-owned subsidiary of USA Inc.  |
greg at cosc.canterbury.ac.nz	   +--------------------------------------+