Am 02.01.2011 22:21, schrieb Manfred_Nowak: > Walter Bright wrote: > >> disallowing (!x&y) expressions > > While `!x&y' may be replaced by `y&!x', > for `!x&&y' an isomorphic change is not possible. > > -manfred (!x) && y may actually be desired, (!x) & y most probably not, so !x&y should be forbidden and !x&&y should not.