# another product.
# This module define several abstract collection classes.
-package abstract_collection
+module abstract_collection
import kernel
# The root of the collection hierarchy.
#
-# Instances of this class offers an iterator method.
+# Collections modelize finite groups of objects, called elements.
+#
+# The specific behavior and representation of collections is determined
+# by the subclasses of the hierarchy.
+#
+# The main service of Collection is to provide a stable `iterator`
+# method usable to retrieve all the elements of the collection.
+#
+# Additional services are provided.
+# For an implementation point of view, Collection provide a basic
+# implementation of these services using the `iterator` method.
+# Subclasses often provide a more efficient implementation.
+#
+# Because of the `iterator` method, Collections instances can use
+# the `for` control structure:
#
-# Collections instances can use the "for" structure:
# var x: Collection[U]
# # ...
# for u in x do
# # u is a U
# # ...
# end
+#
# that is equivalent with
+#
# var x: Collection[U]
# # ...
# var i = x.iterator
# # ...
# i.next
# end
-#
-# This abstract class implements its others methods with an iterator.
-# Subclasses may redefine them with an efficient implementation.
interface Collection[E]
# Get a new iterator on the collection.
fun iterator: Iterator[E] is abstract
- # Iterate over each element of the collection
- fun iterate
- !each(e: E)
- do
- var i = iterator
- while i.is_ok do
- each(i.item)
- i.next
- end
- end
-
# Is there no item in the collection?
- fun is_empty: Bool is abstract
+ #
+ # assert [1,2,3].is_empty == false
+ # assert [1..1[.is_empty == true
+ fun is_empty: Bool do return length == 0
# Number of items in the collection.
- fun length: Int is abstract
-
- # Is `item` in the collection ?
- # Comparisons are done with ==
- fun has(item: E): Bool is abstract
-
- # Is the collection contain only `item`?
- # Comparisons are done with ==
- # Return true if the collection is empty.
- fun has_only(item: E): Bool is abstract
-
- # How many occurrences of `item` are in the collection?
- # Comparisons are done with ==
- fun count(item: E): Int is abstract
-
- # Return one the item of the collection
- fun first: E is abstract
-end
-
-# Naive implementation of collections method
-# You only have to define iterator!
-interface NaiveCollection[E]
- super Collection[E]
- redef fun is_empty do return length == 0
-
- redef fun length
+ #
+ # assert [10,20,30].length == 3
+ # assert [20..30[.length == 10
+ fun length: Int
do
var nb = 0
- for i in self do nb += 1
+ for i in self do nb += 1
return nb
end
- redef fun has(item)
+
+ # Is `item` in the collection ?
+ # Comparisons are done with ==
+ #
+ # assert [1,2,3].has(2) == true
+ # assert [1,2,3].has(9) == false
+ # assert [1..5[.has(2) == true
+ # assert [1..5[.has(9) == false
+ fun has(item: E): Bool
do
for i in self do if i == item then return true
return false
end
- redef fun has_only(item)
+ # Is the collection contain only `item`?
+ # Comparisons are done with ==
+ # Return true if the collection is empty.
+ #
+ # assert [1,1,1].has_only(1) == true
+ # assert [1,2,3].has_only(1) == false
+ # assert [1..1].has_only(1) == true
+ # assert [1..3].has_only(1) == false
+ # assert [3..3[.has_only(1) == true # empty collection
+ #
+ # ENSURE `is_empty implies result == true`
+ fun has_only(item: E): Bool
do
for i in self do if i != item then return false
return true
end
- redef fun count(item)
+ # How many occurrences of `item` are in the collection?
+ # Comparisons are done with ==
+ #
+ # assert [10,20,10].count(10) == 2
+ fun count(item: E): Int
do
var nb = 0
for i in self do if i == item then nb += 1
return nb
end
- redef fun first
+ # Return one the item of the collection
+ #
+ # assert [1,2,3].first == 1
+ fun first: E
do
assert length > 0
return iterator.item
end
+
+ # Is the collection contains all the elements of `other`?
+ #
+ # assert [1,1,1].has_all([1]) == true
+ # assert [1,1,1].has_all([1,2]) == false
+ # assert [1,3,4,2].has_all([1..2]) == true
+ # assert [1,3,4,2].has_all([1..5]) == false
+ fun has_all(other: Collection[E]): Bool
+ do
+ for x in other do if not has(x) then return false
+ return true
+ end
end
# Instances of the Iterator class generates a series of elements, one at a time.
# Synonym of remove since there is only one item
redef fun remove_all(item) do remove(item)
+
+ # Equality is defined on set and means that each set contains the same elements
+ redef fun ==(other)
+ do
+ if not other isa Set[Object] then return false
+ if other.length != length then return false
+ return has_all(other)
+ end
+
+ # because of the law between `==` and `hash`, hash is redefined to be the sum of the hash of the elements
+ redef fun hash
+ do
+ var res = 0
+ for e in self do res += res.hash
+ return res
+ end
end
# MapRead are abstract associative collections: `key` -> `item`.
# Get the item at `key`.
fun [](key: K): E is abstract
+ # Get the item at `key` or return `default` if not in map
+ fun get_or_default(key: K, default: E): E
+ do
+ if has_key(key) then return self[key]
+ return default
+ end
+
# Depreciated alias for `keys.has`
fun has_key(key: K): Bool do return self.keys.has(key)
# Get a new iterator on the map.
fun iterator: MapIterator[K, E] is abstract
- # Iterate over each element of the collection
- fun iterate
- !each(k: K, v: E)
- do
- var i = iterator
- while i.is_ok do
- each(i.key, i.item)
- i.next
- end
- end
-
# Return the point of view of self on the values only.
# Note that `self` and `values` are views on the same data;
# therefore any modification of one is visible on the other.
end
redef fun iterator: IndexedIterator[E] is abstract
+
+ # Two sequences are equals if they have the same items in the same order.
+ redef fun ==(o)
+ do
+ if not o isa SequenceRead[nullable Object] or o is null then return false
+ var l = length
+ if o.length != l then return false
+ var i = 0
+ while i < l do
+ if self[i] != o[i] then return false
+ i += 1
+ end
+ return true
+ end
+
+ # because of the law between `==` and `hash`, hash is redefined to be the sum of the hash of the elements
+ redef fun hash
+ do
+ var res = 0
+ for e in self do res += res.hash
+ return res
+ end
end
# Sequence are indexed collection.
nitlanguage / nit.git / blobdiff