frozen external class BOOLEAN alias "boolean" inherit ANY rename undefine redefine end feature infix "and" (other: like Current): BOOLEAN -- Boolean conjunction with `other' do -- built in end infix "and then" (other: like Current): BOOLEAN -- Boolean semi-strict conjunction with `other' do -- built in end infix "implies" (other: like Current): BOOLEAN -- Boolean implication of `other' -- (semi-strict) do -- built in end prefix "not" : like Current -- Negation do -- bult in end infix "or" (other: like Current): BOOLEAN -- Boolean disjunction with `other' do -- built in end infix "or else" (other: like Current): BOOLEAN -- Boolean semi-strict disjunction with `other' do -- built in end infix "xor" (other: like Current): BOOLEAN -- Boolean exclusive or with `other' do -- built in end end