indexing description: "Truth values, with the boolean operations" expanded class interface BOOLEAN feature -- Access hash_code: INTEGER -- Hash code value -- (from BOOLEAN_REF) ensure -- from HASHABLE good_hash_value: Result >= 0 item: BOOLEAN -- Boolean value -- (from BOOLEAN_REF) feature -- Status report is_hashable: BOOLEAN -- May current object be hashed? -- (True if it is not its type's default.) -- (from BOOLEAN_REF) ensure -- from HASHABLE ok_if_not_default: Result implies (Current /= default) feature -- Element change set_item (b: BOOLEAN) -- Make b the item value. -- (from BOOLEAN_REF) feature -- Basic operations infix "and" (other: like Current): BOOLEAN -- Boolean conjunction with other -- (from BOOLEAN_REF) require -- from BOOLEAN_REF other_exists: other /= void ensure -- from BOOLEAN_REF de_morgan: Result = not (not Current or not other); commutative: Result = (other and Current); consistent_with_semi_strict: Result implies (Current and then other) infix "and then" (other: like Current): BOOLEAN -- Boolean semi-strict conjunction with other -- (from BOOLEAN_REF) require -- from BOOLEAN_REF other_exists: other /= void ensure -- from BOOLEAN_REF de_morgan: Result = not (not Current or else not other) infix "implies" (other: like Current): BOOLEAN -- Boolean implication of other -- (semi-strict) -- (from BOOLEAN_REF) require -- from BOOLEAN_REF other_exists: other /= void ensure -- from BOOLEAN_REF definition: Result = (not Current or else other) prefix "not ": like Current -- Negation -- (from BOOLEAN_REF) infix "or" (other: like Current): BOOLEAN -- Boolean disjunction with other -- (from BOOLEAN_REF) require -- from BOOLEAN_REF other_exists: other /= void ensure -- from BOOLEAN_REF de_morgan: Result = not (not Current and not other); commutative: Result = (other or Current); consistent_with_semi_strict: Result implies (Current or else other) infix "or else" (other: like Current): BOOLEAN -- Boolean semi-strict disjunction with other -- (from BOOLEAN_REF) require -- from BOOLEAN_REF other_exists: other /= void ensure -- from BOOLEAN_REF de_morgan: Result = not (not Current and then not other) infix "xor" (other: like Current): BOOLEAN -- Boolean exclusive or with other -- (from BOOLEAN_REF) require -- from BOOLEAN_REF other_exists: other /= void ensure -- from BOOLEAN_REF definition: Result = ((Current or other) and not (Current and other)) feature -- Output out: STRING -- Printable representation of boolean -- (from BOOLEAN_REF) invariant -- from GENERAL reflexive_equality: standard_is_equal (Current); reflexive_conformance: conforms_to (Current); -- from BOOLEAN_REF involutive_negation: is_equal (not (not Current)); non_contradiction: not (Current and (not Current)); completeness: Current or else (not Current); end -- class BOOLEAN