#
# This file is free software, which comes along with NIT. This software is
# distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
-# without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
# PARTICULAR PURPOSE. You can modify it is you want, provided this header
# is kept unaltered, and a notification of the changes is added.
# You are allowed to redistribute it and sell it, alone or is a part of
# another product.
-# This module define several abtract collection classes.
-package abstract_collection
+# Abstract collection classes and services.
+#
+# TODO specify the behavior on iterators when collections are modified.
+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.
#
-# Colections 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
-# while i.is_ok do
-# var u = i.item # u is a U
-# ...
-# i.next
-# end
+# ~~~nitish
+# var x: Collection[U]
+# # ...
+# for u in x do
+# # u is a U
+# # ...
+# end
+# ~~~
#
-# This abstract class implements its others methods with an iterator.
-# Subclasses may redefine them with an efficient implementation.
+# that is equivalent with the following:
+#
+# ~~~nitish
+# var x: Collection[U]
+# # ...
+# var i = x.iterator
+# while i.is_ok do
+# var u = i.item # u is a U
+# # ...
+# i.next
+# end
+# ~~~
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
+ # Is there no item in the collection?
+ #
+ # 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 ?
- # Comparaisons are done with ==
- fun has(item: E): Bool is abstract
-
- # Is the collection contain only `item' ?
- # Comparaisons are done with ==
- # Return true if the collection is empty.
- fun has_only(item: E): Bool is abstract
-
- # How many occurences of `item' are in the collection ?
- # Comparaisons 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 the first item of the collection
+ #
+ # assert [1,2,3].first == 1
+ fun first: E
do
assert length > 0
return iterator.item
end
+
+ # Does the collection contain at least each element of `other`?
+ #
+ # assert [1,3,4,2].has_all([1..2]) == true
+ # assert [1,3,4,2].has_all([1..5]) == false
+ #
+ # Repeated elements in the collections are not considered.
+ #
+ # assert [1,1,1].has_all([1]) == true
+ # assert [1..5].has_all([1,1,1]) == true
+ #
+ # Note that the default implementation is general and correct for any lawful Collections.
+ # It is memory-efficient but relies on `has` so may be CPU-inefficient for some kind of collections.
+ fun has_all(other: Collection[E]): Bool
+ do
+ for x in other do if not has(x) then return false
+ return true
+ end
+
+ # Does the collection contain exactly all the elements of `other`?
+ #
+ # The same elements must be present in both `self` and `other`,
+ # but the order of the elements in the collections are not considered.
+ #
+ # assert [1..3].has_exactly([3,1,2]) == true # the same elements
+ # assert [1..3].has_exactly([3,1]) == false # 2 is not in the array
+ # assert [1..2].has_exactly([3,1,2]) == false # 3 is not in the range
+ #
+ # Repeated elements must be present in both collections in the same amount.
+ # So basically it is a multi-set comparison.
+ #
+ # assert [1,2,3,2].has_exactly([1,2,2,3]) == true # the same elements
+ # assert [1,2,3,2].has_exactly([1,2,3]) == false # more 2 in the first array
+ # assert [1,2,3].has_exactly([1,2,2,3]) == false # more 2 in the second array
+ #
+ # Note that the default implementation is general and correct for any lawful Collections.
+ # It is memory-efficient but relies on `count` so may be CPU-inefficient for some kind of collections.
+ fun has_exactly(other: Collection[E]): Bool
+ do
+ if length != other.length then return false
+ for e in self do if self.count(e) != other.count(e) then return false
+ return true
+ end
end
# Instances of the Iterator class generates a series of elements, one at a time.
# They are mainly used with collections.
interface Iterator[E]
# The current item.
- # Require `is_ok'.
+ # Require `is_ok`.
fun item: E is abstract
# Jump to the next item.
- # Require `is_ok'.
+ # Require `is_ok`.
fun next is abstract
# Is there a current item ?
fun is_ok: Bool is abstract
+
+ # Iterate over `self`
+ fun iterator: Iterator[E] do return self
+
+ # Post-iteration hook.
+ #
+ # Used to inform `self` that the iteration is over.
+ # Specific iterators can use this to free some resources.
+ #
+ # Is automatically invoked at the end of `for` structures.
+ #
+ # Do nothing by default.
+ fun finish do end
end
# A collection that contains only one item.
+#
+# Used to pass arguments by reference.
+#
+# Also used when one want to give a single element when a full
+# collection is expected
class Container[E]
super Collection[E]
- redef fun first do return _item
+ redef fun first do return item
redef fun is_empty do return false
redef fun length do return 1
- redef fun has(an_item) do return _item == an_item
+ redef fun has(an_item) do return item == an_item
- redef fun has_only(an_item) do return _item == an_item
+ redef fun has_only(an_item) do return item == an_item
redef fun count(an_item)
do
- if _item == an_item then
+ if item == an_item then
return 1
else
return 0
redef fun iterator do return new ContainerIterator[E](self)
- # Create a new instance with a given initial value.
- init(e: E) do _item = e
-
# The stored item
- readable writable var _item: E
+ var item: E is writable
end
# This iterator is quite stupid since it is used for only one item.
-class ContainerIterator[E]
+private class ContainerIterator[E]
super Iterator[E]
redef fun item do return _container.item
- redef fun next do _is_ok = false
+ redef fun next do is_ok = false
- init(c: Container[E]) do _container = c
+ redef var is_ok: Bool = true
- redef readable var _is_ok: Bool = true
-
- var _container: Container[E]
+ var container: Container[E]
end
# Items can be removed from this collection
interface RemovableCollection[E]
super Collection[E]
+
# Remove all items
+ #
+ # var a = [1,2,3]
+ # a.clear
+ # assert a.length == 0
+ #
+ # ENSURE `is_empty`
fun clear is abstract
- # Remove an occucence of `item'
+ # Remove an occucence of `item`
+ #
+ # var a = [1,2,3,1,2,3]
+ # a.remove 2
+ # assert a == [1,3,1,2,3]
fun remove(item: E) is abstract
- # Remove all occurences of `item'
+ # Remove all occurences of `item`
+ #
+ # var a = [1,2,3,1,2,3]
+ # a.remove_all 2
+ # assert a == [1,3,1,3]
fun remove_all(item: E) do while has(item) do remove(item)
end
# Items can be added to these collections.
interface SimpleCollection[E]
super RemovableCollection[E]
+
# Add an item in a collection.
+ #
+ # var a = [1,2]
+ # a.add 3
+ # assert a.has(3) == true
+ # assert a.has(10) == false
+ #
# Ensure col.has(item)
fun add(item: E) is abstract
# Add each item of `coll`.
+ # var a = [1,2]
+ # a.add_all([3..5])
+ # assert a.has(4) == true
+ # assert a.has(10) == false
fun add_all(coll: Collection[E]) do for i in coll do add(i)
end
# Abstract sets.
#
-# Set contains contains only one element with the same value (according to =).
-# var s : Set[E]
-# var a = "Hello"
-# var b = "Hello"
-# ...
-# s.add(a)
-# s.has(b) # --> true
-interface Set[E: Object]
+# Set is a collection without duplicates (according to `==`)
+#
+# var s: Set[String] = new ArraySet[String]
+# var a = "Hello"
+# var b = "Hel" + "lo"
+# # ...
+# s.add(a)
+# assert s.has(b) == true
+interface Set[E]
super SimpleCollection[E]
redef fun has_only(item)
# Synonym of remove since there is only one item
redef fun remove_all(item) do remove(item)
-end
-interface MapRead[K: Object, E]
- # Get the item at `key'.
- fun [](key: K): E is abstract
+ # 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
- # Is there an item at `key'.
- fun has_key(key: K): Bool is abstract
+ # Because of the law between `==` and `hash`, `hash` is redefined to be the sum of the hash of the elements
+ redef fun hash
+ do
+ # 23 is a magic number empirically determined to be not so bad.
+ var res = 23 + length
+ # Note: the order of the elements must not change the hash value.
+ # So, unlike usual hash functions, the accumulator is not combined with itself.
+ for e in self do res += e.hash
+ return res
+ end
- # Get a new iterator on the map.
- fun iterator: MapIterator[K, E] is abstract
+ # Returns the union of this set with the `other` set
+ fun union(other: Set[E]): Set[E]
+ do
+ var nhs = new_set
+ nhs.add_all self
+ nhs.add_all other
+ return nhs
+ end
- # Iterate over each element of the collection
- fun iterate
- !each(e: E)
+ # Returns the intersection of this set with the `other` set
+ fun intersection(other: Set[E]): Set[E]
do
- var i = iterator
- while i.is_ok do
- each(i.item)
- i.next
- end
+ var nhs = new_set
+ for v in self do if other.has(v) then nhs.add(v)
+ return nhs
end
- # Is there no item in the collection ?
- fun is_empty: Bool is abstract
+ # Returns a new instance of `Set`.
+ #
+ # Depends on the subclass, mainly used for copy services
+ # like `union` or `intersection`.
+ protected fun new_set: Set[E] is abstract
+end
- # Number of items in the collection.
- fun length: Int is abstract
+# MapRead are abstract associative collections: `key` -> `item`.
+interface MapRead[K, V]
+ # Get the item at `key`
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # assert x["four"] == 4
+ # # assert x["five"] #=> abort
+ #
+ # If the key is not in the map, `provide_default_value` is called (that aborts by default)
+ # See `get_or_null` and `get_or_default` for safe variations.
+ fun [](key: K): V is abstract
+
+ # Get the item at `key` or null if `key` is not in the map.
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # assert x.get_or_null("four") == 4
+ # assert x.get_or_null("five") == null
+ #
+ # Note: use `has_key` and `[]` if you need the distinction between a key associated with null, and no key.
+ fun get_or_null(key: K): nullable V
+ do
+ if has_key(key) then return self[key]
+ return null
+ end
- # Is `item' in the collection ?
- # Comparaisons are done with ==
- fun has(item: E): Bool is abstract
+ # Get the item at `key` or return `default` if not in map
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # assert x.get_or_default("four", 40) == 4
+ # assert x.get_or_default("five", 50) == 50
+ #
+ fun get_or_default(key: K, default: V): V
+ do
+ if has_key(key) then return self[key]
+ return default
+ end
- # Is the collection contain only `item' ?
- # Comparaisons are done with ==
- # Return true if the collection is empty.
- fun has_only(item: E): Bool is abstract
+ # Is there an item associated with `key`?
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # assert x.has_key("four") == true
+ # assert x.has_key("five") == false
+ #
+ # By default it is a synonymous to `keys.has` but could be redefined with a direct implementation.
+ fun has_key(key: K): Bool do return self.keys.has(key)
- # How many occurences of `item' are in the collection ?
- # Comparaisons are done with ==
- fun count(item: E): Int is abstract
+ # Get a new iterator on the map.
+ fun iterator: MapIterator[K, V] is abstract
+
+ # 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.
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # assert x.values.has(4) == true
+ # assert x.values.has(5) == false
+ fun values: Collection[V] is abstract
+
+ # Return the point of view of self on the keys only.
+ # Note that `self` and `keys` are views on the same data;
+ # therefore any modification of one is visible on the other.
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # assert x.keys.has("four") == true
+ # assert x.keys.has("five") == false
+ fun keys: Collection[K] is abstract
+
+ # Is there no item in the collection?
+ #
+ # var x = new HashMap[String, Int]
+ # assert x.is_empty == true
+ # x["four"] = 4
+ # assert x.is_empty == false
+ fun is_empty: Bool is abstract
- # Return one the item of the collection
- fun first: E is abstract
+ # Number of items in the collection.
+ #
+ # var x = new HashMap[String, Int]
+ # assert x.length == 0
+ # x["four"] = 4
+ # assert x.length == 1
+ # x["five"] = 5
+ # assert x.length == 2
+ fun length: Int is abstract
+
+ # Called by the underling implementation of `[]` to provide a default value when a `key` has no value
+ # By default the behavior is to abort.
+ #
+ # Note: the value is returned *as is*, implementations may want to store the value in the map before returning it
+ # @toimplement
+ protected fun provide_default_value(key: K): V do abort
+
+ # Does `self` and `other` have the same keys associated with the same values?
+ #
+ # ~~~
+ # var a = new HashMap[String, Int]
+ # var b = new ArrayMap[Object, Numeric]
+ # assert a == b
+ # a["one"] = 1
+ # assert a != b
+ # b["one"] = 1
+ # assert a == b
+ # b["one"] = 2
+ # assert a != b
+ # ~~~
+ redef fun ==(other)
+ do
+ if not other isa MapRead[nullable Object, nullable Object] then return false
+ if other.length != self.length then return false
+ for k, v in self do
+ if not other.has_key(k) then return false
+ if other[k] != v then return false
+ end
+ return true
+ end
end
-# Maps are associative collections: `key' -> `item'.
+# Maps are associative collections: `key` -> `item`.
#
# The main operator over maps is [].
#
-# var map: Map[U, V]
-# ...
-# map[u1] = v1 # Associate 'v1' to 'u1'
-# map[u2] = v2 # Associate 'v2' to 'u2'
-# map[u1] # -> v1
-# map[u2] # -> v2
-# map.has_key(u1) # -> true
-# map.has_key(u3) # -> false
-interface Map[K: Object, E]
- super MapRead[K, E]
- # Set the`item' at `key'.
- fun []=(key: K, item: E) is abstract
-
- # Remove the item at `key'
- fun remove_at(key: K) is abstract
-
- # Add each (key,value) of `map' into `self'.
- # If a same key exists in `map' and `self', then the value in self is discarded.
- fun recover_with(map: Map[K, E])
+# var map: Map[String, Int] = new ArrayMap[String, Int]
+# # ...
+# map["one"] = 1 # Associate 'one' to '1'
+# map["two"] = 2 # Associate 'two' to '2'
+# assert map["one"] == 1
+# assert map["two"] == 2
+#
+# Instances of maps can be used with the for structure
+#
+# for key, value in map do
+# assert (key == "one" and value == 1) or (key == "two" and value == 2)
+# end
+#
+# The keys and values in the map can also be manipulated directly with the `keys` and `values` methods.
+#
+# assert map.keys.has("one") == true
+# assert map.keys.has("tree") == false
+# assert map.values.has(1) == true
+# assert map.values.has(3) == false
+#
+interface Map[K, V]
+ super MapRead[K, V]
+
+ # Set the `value` at `key`.
+ #
+ # Values can then get retrieved with `[]`.
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # assert x["four"] == 4
+ #
+ # If the key was associated with a value, this old value is discarded
+ # and replaced with the new one.
+ #
+ # x["four"] = 40
+ # assert x["four"] == 40
+ # assert x.values.has(4) == false
+ #
+ fun []=(key: K, value: V) is abstract
+
+ # Add each (key,value) of `map` into `self`.
+ # If a same key exists in `map` and `self`, then the value in self is discarded.
+ #
+ # It is the analogous of `SimpleCollection::add_all`
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # x["five"] = 5
+ # var y = new HashMap[String, Int]
+ # y["four"] = 40
+ # y["nine"] = 90
+ # x.recover_with y
+ # assert x["four"] == 40
+ # assert x["five"] == 5
+ # assert x["nine"] == 90
+ fun recover_with(map: MapRead[K, V])
do
var i = map.iterator
while i.is_ok do
end
# Remove all items
+ #
+ # var x = new HashMap[String, Int]
+ # x["four"] = 4
+ # x.clear
+ # assert x.keys.has("four") == false
+ #
+ # ENSURE `is_empty`
fun clear is abstract
- # Remove an occucence of `item'
- fun remove(item: E) is abstract
+ redef fun values: RemovableCollection[V] is abstract
- # Remove all occurences of `item'
- fun remove_all(item: E) do while has(item) do remove(item)
+ redef fun keys: RemovableCollection[K] is abstract
end
# Iterators for Map.
-interface MapIterator[K: Object, E]
+interface MapIterator[K, V]
# The current item.
- # Require `is_ok'.
- fun item: E is abstract
+ # Require `is_ok`.
+ fun item: V is abstract
# The key of the current item.
- # Require `is_ok'.
+ # Require `is_ok`.
fun key: K is abstract
# Jump to the next item.
- # Require `is_ok'.
+ # Require `is_ok`.
fun next is abstract
# Is there a current item ?
fun is_ok: Bool is abstract
- # Set a new `item' at `key'.
+ # Set a new `item` at `key`.
#fun item=(item: E) is abstract
+
+ # Post-iteration hook.
+ #
+ # Used to inform `self` that the iteration is over.
+ # Specific iterators can use this to free some resources.
+ #
+ # Is automatically invoked at the end of `for` structures.
+ #
+ # Do nothing by default.
+ fun finish do end
+end
+
+# Iterator on a 'keys' point of view of a map
+class MapKeysIterator[K, V]
+ super Iterator[K]
+ # The original iterator
+ var original_iterator: MapIterator[K, V]
+
+ redef fun is_ok do return self.original_iterator.is_ok
+ redef fun next do self.original_iterator.next
+ redef fun item do return self.original_iterator.key
+end
+
+# Iterator on a 'values' point of view of a map
+class MapValuesIterator[K, V]
+ super Iterator[V]
+ # The original iterator
+ var original_iterator: MapIterator[K, V]
+
+ redef fun is_ok do return self.original_iterator.is_ok
+ redef fun next do self.original_iterator.next
+ redef fun item do return self.original_iterator.item
end
-# Indexed collection are ordoned collections.
-# The first item is 0. The last is `length'-1.
+# Sequences are indexed collections.
+# The first item is 0. The last is `length-1`.
+#
+# The order is the main caracteristic of sequence
+# and all concrete implementation of sequences are basically interchangeable.
interface SequenceRead[E]
super Collection[E]
+
# Get the first item.
- # Is equivalent with `self'[0].
+ # Is equivalent with `self[0]`.
+ #
+ # var a = [1,2,3]
+ # assert a.first == 1
+ #
+ # REQUIRE `not is_empty`
redef fun first
do
assert not_empty: not is_empty
return self[0]
end
+ # Return the index-th element of the sequence.
+ # The first element is 0 and the last is `length-1`
+ # If index is invalid, the program aborts
+ #
+ # var a = [10,20,30]
+ # assert a[0] == 10
+ # assert a[1] == 20
+ # assert a[2] == 30
+ #
+ # REQUIRE `index >= 0 and index < length`
fun [](index: Int): E is abstract
# Get the last item.
- # Is equivalent with `self'[`length'-1].
+ # Is equivalent with `self[length-1]`.
+ #
+ # var a = [1,2,3]
+ # assert a.last == 3
+ #
+ # REQUIRE `not is_empty`
fun last: E
do
assert not_empty: not is_empty
return self[length-1]
end
- # Return the index of the first occurence of `item'.
- # Return -1 if `item' is not found
- fun index_of(item: E): Int
+ # The index of the first occurrence of `item`.
+ # Return -1 if `item` is not found.
+ # Comparison is done with `==`.
+ #
+ # var a = [10,20,30,10,20,30]
+ # assert a.index_of(20) == 1
+ # assert a.index_of(40) == -1
+ fun index_of(item: E): Int do return index_of_from(item, 0)
+
+ # The index of the last occurrence of `item`.
+ # Return -1 if `item` is not found.
+ # Comparison is done with `==`.
+ #
+ # var a = [10,20,30,10,20,30]
+ # assert a.last_index_of(20) == 4
+ # assert a.last_index_of(40) == -1
+ fun last_index_of(item: E): Int do return last_index_of_from(item, length-1)
+
+ # The index of the first occurrence of `item`, starting from pos.
+ # Return -1 if `item` is not found.
+ # Comparison is done with `==`.
+ #
+ # var a = [10,20,30,10,20,30]
+ # assert a.index_of_from(20, 3) == 4
+ # assert a.index_of_from(20, 4) == 4
+ # assert a.index_of_from(20, 5) == -1
+ fun index_of_from(item: E, pos: Int): Int
do
+ var p = 0
var i = iterator
while i.is_ok do
- if i.item == item then return i.index
+ if p>=pos and i.item == item then return i.index
i.next
+ p += 1
end
return -1
end
+ # The index of the last occurrence of `item` starting from `pos` and decrementing.
+ # Return -1 if `item` is not found.
+ # Comparison is done with `==`.
+ #
+ # var a = [10,20,30,10,20,30]
+ # assert a.last_index_of_from(20, 2) == 1
+ # assert a.last_index_of_from(20, 1) == 1
+ # assert a.last_index_of_from(20, 0) == -1
+ fun last_index_of_from(item: E, pos: Int): Int
+ do
+ var res = -1
+ var p = 0
+ var i = iterator
+ while i.is_ok do
+ if p>pos then break
+ if i.item == item then res = p
+ i.next
+ p += 1
+ end
+ return res
+ end
+
+ # Two sequences are equals if they have the same items in the same order.
+ #
+ # var a = new List[Int]
+ # a.add(1)
+ # a.add(2)
+ # a.add(3)
+ # assert a == [1,2,3]
+ # assert a != [1,3,2]
+ redef fun ==(o)
+ do
+ if not o isa SequenceRead[nullable Object] 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
+ # The 17 and 2/3 magic numbers were determined empirically.
+ # Note: the standard hash functions djb2, sbdm and fnv1 were also
+ # tested but were comparable (or worse).
+ var res = 17 + length
+ for e in self do
+ res = res * 3 / 2
+ if e != null then res += e.hash
+ end
+ return res
+ end
+
redef fun iterator: IndexedIterator[E] is abstract
+
+ # Gets a new Iterator starting at position `pos`
+ #
+ # var iter = [10,20,30,40,50].iterator_from(2)
+ # assert iter.to_a == [30, 40, 50]
+ fun iterator_from(pos: Int): IndexedIterator[E]
+ do
+ var res = iterator
+ while pos > 0 and res.is_ok do
+ res.next
+ pos -= 1
+ end
+ return res
+ end
+
+ # Gets an iterator starting at the end and going backwards
+ #
+ # var reviter = [1,2,3].reverse_iterator
+ # assert reviter.to_a == [3,2,1]
+ fun reverse_iterator: IndexedIterator[E] is abstract
+
+ # Gets an iterator on the chars of self starting from `pos`
+ #
+ # var reviter = [10,20,30,40,50].reverse_iterator_from(2)
+ # assert reviter.to_a == [30,20,10]
+ fun reverse_iterator_from(pos: Int): IndexedIterator[E]
+ do
+ var res = reverse_iterator
+ while pos > 0 and res.is_ok do
+ res.next
+ pos -= 1
+ end
+ return res
+ end
end
-# Indexed collection are ordoned collections.
-# The first item is 0. The last is `length'-1.
+# Sequence are indexed collection.
+# The first item is 0. The last is `length-1`.
interface Sequence[E]
super SequenceRead[E]
super SimpleCollection[E]
+
# Set the first item.
- # Is equivalent with `self'[0] = `item'.
+ # Is equivalent with `self[0] = item`.
+ #
+ # var a = [1,2,3]
+ # a.first = 10
+ # assert a == [10,2,3]
fun first=(item: E)
do self[0] = item end
# Set the last item.
- # Is equivalent with `self'[length-1] = `item'.
- fun last=(item: E)
- do
+ # Is equivalent with `self[length-1] = item`.
+ #
+ # var a = [1,2,3]
+ # a.last = 10
+ # assert a == [1,2,10]
+ #
+ # If the sequence is empty, `last=` is equivalent with `self[0]=` (thus with `first=`)
+ #
+ # var b = new Array[Int]
+ # b.last = 10
+ # assert b == [10]
+ fun last=(item: E)
+ do
var l = length
if l > 0 then
self[l-1] = item
end
end
- # A synonym of `push'
+ # A synonym of `push`
redef fun add(e) do push(e)
- # Add an item after the last.
+ # Add an item after the last one.
+ #
+ # var a = [1,2,3]
+ # a.push(10)
+ # a.push(20)
+ # assert a == [1,2,3,10,20]
fun push(e: E) is abstract
# Add each item of `coll` after the last.
- fun append(coll: Collection[E]) do for i in coll do push(i)
+ #
+ # var a = [1,2,3]
+ # a.append([7..9])
+ # assert a == [1,2,3,7,8,9]
+ #
+ # Alias of `add_all`
+ fun append(coll: Collection[E]) do add_all(coll)
# Remove the last item.
+ #
+ # var a = [1,2,3]
+ # assert a.pop == 3
+ # assert a.pop == 2
+ # assert a == [1]
+ #
+ # REQUIRE `not is_empty`
fun pop: E is abstract
- # Add an item before the last.
+ # Add an item before the first one.
+ #
+ # var a = [1,2,3]
+ # a.unshift(10)
+ # a.unshift(20)
+ # assert a == [20,10,1,2,3]
fun unshift(e: E) is abstract
+ # Add all items of `coll` before the first one.
+ #
+ # var a = [1,2,3]
+ # a.prepend([7..9])
+ # assert a == [7,8,9,1,2,3]
+ #
+ # Alias of `insert_at(coll, 0)`
+ fun prepend(coll: Collection[E]) do insert_all(coll, 0)
+
# Remove the first item.
- # The second item become the first.
+ # The second item thus become the first.
+ #
+ # var a = [1,2,3]
+ # assert a.shift == 1
+ # assert a.shift == 2
+ # assert a == [3]
+ #
+ # REQUIRE `not is_empty`
fun shift: E is abstract
- # Set the`item' at `index'.
+ # Set the `item` at `index`.
+ #
+ # var a = [10,20,30]
+ # a[1] = 200
+ # assert a == [10,200,30]
+ #
+ # like with `[]`, index should be between `0` and `length-1`
+ # However, if `index==length`, `[]=` works like `push`.
+ #
+ # a[3] = 400
+ # assert a == [10,200,30,400]
+ #
+ # REQUIRE `index >= 0 and index <= length`
fun []=(index: Int, item: E) is abstract
- # Remove the item at `index' and shift all following elements
+ # Insert an element at a given position, following elements are shifted.
+ #
+ # var a = [10, 20, 30, 40]
+ # a.insert(100, 2)
+ # assert a == [10, 20, 100, 30, 40]
+ #
+ # REQUIRE `index >= 0 and index <= length`
+ # ENSURE `self[index] == item`
+ fun insert(item: E, index: Int) is abstract
+
+ # Insert all elements at a given position, following elements are shifted.
+ #
+ # var a = [10, 20, 30, 40]
+ # a.insert_all([100..102], 2)
+ # assert a == [10, 20, 100, 101, 102, 30, 40]
+ #
+ # REQUIRE `index >= 0 and index <= length`
+ # ENSURE `self[index] == coll.first`
+ fun insert_all(coll: Collection[E], index: Int)
+ do
+ assert index >= 0 and index < length
+ if index == length then
+ add_all(coll)
+ end
+ for c in coll do
+ insert(c, index)
+ index += 1
+ end
+ end
+
+ # Remove the item at `index` and shift all following elements
+ #
+ # var a = [10,20,30]
+ # a.remove_at(1)
+ # assert a == [10,30]
+ #
+ # REQUIRE `index >= 0 and index < length`
fun remove_at(index: Int) is abstract
end
fun index: Int is abstract
end
-# Associatives arrays that internally uses couples to represent each (key, value) pairs.
-interface CoupleMap[K: Object, E]
- super Map[K, E]
+# Associative arrays that internally uses couples to represent each (key, value) pairs.
+# This is an helper class that some specific implementation of Map may implements.
+interface CoupleMap[K, V]
+ super Map[K, V]
+
# Return the couple of the corresponding key
# Return null if the key is no associated element
- protected fun couple_at(key: K): nullable Couple[K, E] is abstract
+ protected fun couple_at(key: K): nullable Couple[K, V] is abstract
+
+ # Return a new iteralot on all couples
+ # Used to provide `iterator` and others
+ protected fun couple_iterator: Iterator[Couple[K,V]] is abstract
+
+ redef fun iterator do return new CoupleMapIterator[K,V](couple_iterator)
redef fun [](key)
do
var c = couple_at(key)
if c == null then
- abort
+ return provide_default_value(key)
else
return c.second
end
# Iterator on CoupleMap
#
-# Actually is is a wrapper around an iterator of the internal array of the map.
-class CoupleMapIterator[K: Object, E]
- super MapIterator[K, E]
+# Actually it is a wrapper around an iterator of the internal array of the map.
+private class CoupleMapIterator[K, V]
+ super MapIterator[K, V]
redef fun item do return _iter.item.second
#redef fun item=(e) do _iter.item.second = e
redef fun is_ok do return _iter.is_ok
redef fun next
- do
+ do
_iter.next
end
- var _iter: Iterator[Couple[K,E]]
-
- init(i: Iterator[Couple[K,E]]) do _iter = i
+ var iter: Iterator[Couple[K,V]]
end
# Some tools ###################################################################
class Couple[F, S]
# The first element of the couple.
- readable writable var _first: F
+ var first: F is writable
# The second element of the couple.
- readable writable var _second: S
-
- # Create a new instance with a first and a second object.
- init(f: F, s: S)
- do
- _first = f
- _second = s
- end
+ var second: S is writable
end
nitlanguage / nit.git / blobdiff