indexing description: "Data structures of the most general kind, used to hold zero or more items." names: access access: membership contents: generic deferred class interface CONTAINER [G] feature -- Access has (v: G): BOOLEAN -- Does structure include v? -- (Reference or object equality, -- based on object_comparison.) ensure not_found_in_empty: Result implies not empty feature -- Status report changeable_comparison_criterion: BOOLEAN -- May object_comparison be changed? -- (Answer: yes by default.) empty: BOOLEAN -- Is there no element? object_comparison: BOOLEAN -- Must search operations use equal rather than = -- for comparing references? (Default: no, use =.) feature -- Status setting compare_objects -- Ensure that future search operations will use equal -- rather than = for comparing references. require changeable_comparison_criterion ensure object_comparison compare_references -- Ensure that future search operations will use = -- rather than equal for comparing references. require changeable_comparison_criterion ensure reference_comparison: not object_comparison feature -- Conversion linear_representation: LINEAR [G] -- Representation as a linear structure invariant -- from GENERAL reflexive_equality: standard_is_equal (Current); reflexive_conformance: conforms_to (Current); end -- class CONTAINER