> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Simon Cozens > > I'm not sure that having quaternary logic in Perl 6 is necessarily a good > idea. Why stop only at four states?
Indeed: undef, unset (disagreeable undef, a la NaN), nocare (always matches), true, false. Plus "but tentative" and "but forcing" modifiers, and junction support for 'none(true)'. Total about twelve possible "states" plus junctions, of which eight or nine would be 'useful', and only three would be knowingly used. Most users would never see "nocare", and rarely see "unset." But NULL would map directly to it (hello, DBI), the complex operators could use it, and occasionally having the core logic code do the right thing would be a win, like the xor example. =Austin
