#
# 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 abstract collection classes.
+# Abstract collection classes and services.
+#
+# TODO specify the behavior on iterators when collections are modified.
module abstract_collection
import kernel
return nb
end
-
# Is `item` in the collection ?
# Comparisons are done with ==
#
return nb
end
- # Return one the item of the collection
+ # Return the first item of the collection
#
# assert [1,2,3].first == 1
fun first: E
# Is there a current item ?
fun is_ok: Bool is abstract
+
+ # Iterate over `self`
+ fun iterator: Iterator[E] do return self
end
# A collection that contains only one item.
+#
+# Used to pass arguments by reference.
+#
+# Also used when one want to give asingle 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
+ 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 readable var _is_ok: Bool = true
+ redef var is_ok: Bool = true
- var _container: Container[E]
+ private 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`
+ #
+ # 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`
+ #
+ # 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 ==).
+# Set is a collection without duplicates (according to `==`)
+#
# var s: Set[String] = new ArraySet[String]
# var a = "Hello"
# var b = "Hel" + "lo"
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
+ # 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
+ # 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
+
+ # 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
+
+ # Returns the intersection of this set with the `other` set
+ fun intersection(other: Set[E]): Set[E]
+ do
+ var nhs = new_set
+ for v in self do if other.has(v) then nhs.add(v)
+ return nhs
+ end
+
+ protected fun new_set: Set[E] is abstract
end
# MapRead are abstract associative collections: `key` -> `item`.
interface MapRead[K: Object, E]
- # Get the item at `key`.
+ # 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): E 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 bewteen a key associated with null, and no key.
+ fun get_or_null(key: K): nullable E
+ do
+ if has_key(key) then return self[key]
+ return null
+ end
+
# 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: E): E
do
if has_key(key) then return self[key]
# 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[E] 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
# 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): E do abort
end
# Maps are associative collections: `key` -> `item`.
#
interface Map[K: Object, E]
super MapRead[K, E]
- # Set the`item` at `key`.
- fun []=(key: K, item: E) is abstract
+
+ # 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 discarted
+ # and replaced with the new one.
+ #
+ # x["four"] = 40
+ # assert x["four"] == 40
+ # assert x.values.has(4) == false
+ #
+ fun []=(key: K, value: E) 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: Map[K, E])
do
var i = map.iterator
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
redef fun values: RemovableCollection[E] is abstract
class MapKeysIterator[K: Object, V]
super Iterator[K]
# The original iterator
- var iterator: MapIterator[K, V]
+ var original_iterator: MapIterator[K, V]
- redef fun is_ok do return self.iterator.is_ok
- redef fun next do self.iterator.next
- redef fun item do return self.iterator.key
+ 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: Object, V]
super Iterator[V]
# The original iterator
- var iterator: MapIterator[K, V]
+ var original_iterator: MapIterator[K, V]
- redef fun is_ok do return self.iterator.is_ok
- redef fun next do self.iterator.next
- redef fun item do return self.iterator.item
+ 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
# 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]`.
+ #
+ # 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 if `length-1`
+ # 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]`.
+ #
+ # 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 occurrence of `item`.
- # Return -1 if `item` is not found
- # Comparison is done with ==
- 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
- redef fun iterator: IndexedIterator[E] is abstract
+ # 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
return true
end
- # because of the law between `==` and `hash`, hash is redefined to be the sum of the hash of the elements
+ # 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
+ # 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
# Set the first 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
+ #
+ # 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
# 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`.
+ #
+ # 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
+ # 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
end
# 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: Object, E]
super Map[K, E]
+
# 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
+ # Return a new iteralot on all couples
+ # Used to provide `iterator` and others
+ protected fun couple_iterator: Iterator[Couple[K,E]] is abstract
+
+ redef fun iterator do return new CoupleMapIterator[K,E](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]
+# Actually it is a wrapper around an iterator of the internal array of the map.
+private class CoupleMapIterator[K: Object, E]
super MapIterator[K, E]
redef fun item do return _iter.item.second
redef fun is_ok do return _iter.is_ok
redef fun next
- do
+ do
_iter.next
end
- var _iter: Iterator[Couple[K,E]]
+ private var iter: Iterator[Couple[K,E]]
init(i: Iterator[Couple[K,E]]) do _iter = i
end
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
+ var second: S is writable
# Create a new instance with a first and a second object.
init(f: F, s: S)
do
- _first = f
- _second = s
+ first = f
+ second = s
end
end
nitlanguage / nit.git / blobdiff