class interface AVL_SET[E->COMPARABLE]
--
-- Definition of a mathematical set of comparable objects. All common
-- operations on mathematical sets are available.
--
creation
make
-- Creation of an empty SET.
ensure
is_empty
from_collection (model: COLLECTION[E])
feature(s) from SET
-- Counting:
count: INTEGER
-- Cardinality of the set (i.e. actual count of stored elements).
is_empty: BOOLEAN
-- Is the set empty?
ensure
Result = (count = 0)
feature(s) from SET
-- Adding and removing:
add (e: E)
-- Add a new item to the set: the mathematical definition of
-- adding in a set is followed.
require
e /= Void
ensure
added: has(e);
not_in_then_added: not old has(e) implies count = old count + 1;
in_then_not_added: old has(e) implies count = old count
remove (e: E)
-- Remove item e from the set: the mathematical definition of
-- removing from a set is followed.
require
e /= Void
ensure
removed: not has(e);
not_in_not_removed: not old has(e) implies count = old count;
in_then_removed: old has(e) implies count = old count - 1
clear_count
-- Empty the current set (is_empty is True after that call). If possible, the actual implementation
-- is supposed to keep its internal storage area in order to refill Current in an efficient way.
-- See also clear_count_and_capacity to select the most appropriate.
ensure
is_empty
clear_count_and_capacity
-- Empty the current set (is_empty is True after that call). If possible, the actual implementation
-- is supposed to release its internal storage area for this memory to be used by other objects.
-- See also clear_count to select the most appropriate.
ensure
is_empty: count = 0
feature(s) from SET
-- Looking and searching:
has (e: E): BOOLEAN
-- Is element e in the set?
require
e /= Void
ensure
Result implies not is_empty
fast_has (e: E): BOOLEAN
-- Is element e in the set?
require
e /= Void
ensure
Result implies not is_empty
reference_at (e: E): E
-- When Is element e in the set?
require
e /= Void;
not e.is_expanded_type
ensure
has(e) implies Result /= Void
feature(s) from SET
-- To provide iterating facilities:
lower: INTEGER
upper: INTEGER
ensure
Result = count
valid_index (index: INTEGER): BOOLEAN
ensure
Result = index.in_range(lower,upper)
item (index: INTEGER): E
-- Return the item indexed by index.
require
valid_index(index)
ensure
has(Result)
get_new_iterator: ITERATOR[E]
feature(s) from SET
-- Mathematical operations:
union (other: like Current)
-- Make the union of the Current set with other.
require
other /= Void
ensure
count <= old count + other.count
infix "+" (other: like Current): like Current
-- Return the union of the Current set with other.
require
other /= Void
ensure
Result.count <= count + other.count;
Current.is_subset_of(Result) and then other.is_subset_of(Result)
intersection (other: like Current)
-- Make the intersection of the Current set with other.
require
other /= Void
ensure
count <= other.count.min(old count)
infix "^" (other: like Current): like Current
-- Return the intersection of the Current set with other.
require
other /= Void
ensure
Result.count <= other.count.min(count);
Result.is_subset_of(Current) and then Result.is_subset_of(other)
minus (other: like Current)
-- Make the set Current - other.
require
other /= Void
ensure
count <= old count
infix "-" (other: like Current): like Current
-- Return the set Current - other.
require
other /= Void
ensure
Result.count <= count;
Result.is_subset_of(Current)
feature(s) from SET
-- Comparison:
is_subset_of (other: like Current): BOOLEAN
-- Is the Current set a subset of other?
require
other /= Void
ensure
Result implies count <= other.count
is_disjoint_from (other: like Current): BOOLEAN
-- Is the Current set disjoint from other ?
require
other /= Void
ensure
Result = (Current ^ other).is_empty
is_equal (other: like Current): BOOLEAN
-- Is the Current set equal to other?
require
other /= Void
ensure
double_inclusion: Result = (is_subset_of(other) and other.is_subset_of(Current));
generating_type = other.generating_type implies Result = other.is_equal(Current)
feature(s) from SET
copy (other: like Current)
-- Copy 'other' into the current set
require
same_dynamic_type(other)
ensure
is_equal(other)
from_collection (model: COLLECTION[E])
feature(s) from SET
-- Agents based features:
do_all (action: ROUTINE[ANY,TUPLE[COMPARABLE]])
-- Apply action to every item of Current.
for_all (test: FUNCTION[ANY,TUPLE[COMPARABLE],BOOLEAN]): BOOLEAN
-- Do all items satisfy test?
exists (test: FUNCTION[ANY,TUPLE[COMPARABLE],BOOLEAN]): BOOLEAN
-- Does at least one item satisfy test?
feature(s) from SET
make
-- Creation of an empty SET.
ensure
is_empty
feature(s) from AVL_HELPER
-- Interface used by descendants:
new_node (e: E): AVL_SET_NODE[E]
require
e /= Void
ensure
--old lost_nodes.count > 0 implies
-- (lost_nodes.count = old lost_nodes.count - 1
-- and then Result = old lost_nodes.last)
discard_node (n: AVL_SET_NODE[E])
require
n /= Void
ensure
discarded: lost_nodes /= Void implies lost_nodes.count = old lost_nodes.count + 1
feature(s) from AVL_HELPER
-- Internals:
lost_nodes: COLLECTION[AVL_SET_NODE[E]]
-- Keeps discarded nodes to avoid memory leaks. Should be a once function. May return Void if lost
-- nodes are not kept.
a_new_node (e: E): AVL_SET_NODE[E]
require
e /= Void
ensure
Result /= Void;
Result.item = e
feature(s) from SAFE_EQUAL
test (e1, e2: E): BOOLEAN
-- In order to avoid run-time type errors, feature safe_equal calls
-- is_equal only when e1 and e2 have exactly the same dynamic
-- type. Furthermore, this feature avoids argument passing from some
-- expanded type to the corresponding reference type (no automatic
-- allocation of some reference type during the comparison).
safe_equal (e1, e2: E): BOOLEAN
-- In order to avoid run-time type errors, feature safe_equal calls
-- is_equal only when e1 and e2 have exactly the same dynamic
-- type. Furthermore, this feature avoids argument passing from some
-- expanded type to the corresponding reference type (no automatic
-- allocation of some reference type during the comparison).
feature(s) from AVL_SET
root: AVL_SET_NODE[E]
feature(s) from AVL_SET
debug_string: STRING
feature(s) from AVL_SET
-- Iterating internals:
build_map
require
build_needed: map_dirty
ensure
build_done: not map_dirty
map: FAST_ARRAY[AVL_SET_NODE[E]]
-- Elements in a row for iteration. See build_map.
map_dirty: BOOLEAN
-- True when the map needs to be built again for the iterators. See
-- build_map.
feature(s) from AVL_SET
-- from AVL_HELPER
node_memo: MEMO[AVL_SET_NODE[E]]
inserted_node_memo: MEMO[AVL_SET_NODE[E]]
invariant
not map_dirty implies map.count = count;
count > 0 implies root /= Void and then root.count = count;
end of AVL_SET[E->COMPARABLE]