EiffelBase class
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Eiffel Class
indexing
description: "Subsets with the associated operations, without commitment to a particular representation";
status: "See notice at end of class";
names: subset, set;
access: membership;
contents: generic;
date: "$Date: 2007-03-30 11:10:11 -0800 (Fri, 30 Mar 2007) $";
revision: "$Revision: 95354 $"
deferred class SUBSET [G]
inherit
SET [G]
feature -- Comparison
is_subset (other: like Current): BOOLEAN is
-- Is current set a subset of other?
require
set_exists: other /= void;
same_rule: object_comparison = other.object_comparison
deferred
end;
is_superset (other: like Current): BOOLEAN is
-- Is current set a superset of other?
require
set_exists: other /= void;
same_rule: object_comparison = other.object_comparison
do
Result := other.is_subset (Current)
end;
disjoint (other: like Current): BOOLEAN is
-- Do current set and other have no
-- items in common?
require
set_exists: other /= void;
same_rule: object_comparison = other.object_comparison
local
temp: like Current
do
if notempty then
temp := duplicate (count);
temp.intersect (other);
Result := temp.empty
else
Result := true
end
end;
feature -- Duplication
duplicate (n: INTEGER): SUBSET [G] is
-- New structure containing min (n, count)
-- items from current structure
require
non_negative: n >= 0
deferred
ensure
correct_count_1: n <= count implies Result.count = n;
correct_count_2: n >= count implies Result.count = count
end;
feature -- Basic operations
intersect (other: like Current) is
-- Remove all items not in other.
require
set_exists: other /= void;
same_rule: object_comparison = other.object_comparison
deferred
ensure
is_subset_other: is_subset (other)
end;
merge (other: like Current) is
-- Add all items of other.
require
set_exists: other /= void;
same_rule: object_comparison = other.object_comparison
deferred
ensure
is_superset: is_superset (other)
end;
subtract (other: like Current) is
-- Remove all items also in other.
require
set_exists: other /= void;
same_rule: object_comparison = other.object_comparison
deferred
ensure
is_disjoint: disjoint (other)
end;
symdif (other: like Current) is
-- Remove all items also in other, and add all
-- items of other not already present.
require
set_exists: other /= void;
same_rule: object_comparison = other.object_comparison
local
temp: like Current
do
temp := duplicate (count);
temp.intersect (other);
merge (other);
subtract (temp)
end;
end -- class SUBSET
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