1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2004-2008 Jean Privat <jean@pryen.org>
5 # This file is free software, which comes along with NIT. This software is
6 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
7 # without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
8 # PARTICULAR PURPOSE. You can modify it is you want, provided this header
9 # is kept unaltered, and a notification of the changes is added.
10 # You are allowed to redistribute it and sell it, alone or is a part of
13 # Abstract collection classes and services.
15 # TODO specify the behavior on iterators when collections are modified.
16 module abstract_collection
20 # The root of the collection hierarchy.
22 # Collections modelize finite groups of objects, called elements.
24 # The specific behavior and representation of collections is determined
25 # by the subclasses of the hierarchy.
27 # The main service of Collection is to provide a stable `iterator`
28 # method usable to retrieve all the elements of the collection.
30 # Additional services are provided.
31 # For an implementation point of view, Collection provide a basic
32 # implementation of these services using the `iterator` method.
33 # Subclasses often provide a more efficient implementation.
35 # Because of the `iterator` method, Collections instances can use
36 # the `for` control structure.
39 # var x: Collection[U]
47 # that is equivalent with the following:
50 # var x: Collection[U]
54 # var u = i.item # u is a U
59 interface Collection[E
]
60 # Get a new iterator on the collection.
61 fun iterator
: Iterator[E
] is abstract
63 # Is there no item in the collection?
65 # assert [1,2,3].is_empty == false
66 # assert [1..1[.is_empty == true
67 fun is_empty
: Bool do return length
== 0
69 # Alias for `not is_empty`.
71 # Some people prefer to have conditions grammatically easier to read.
73 # assert [1,2,3].not_empty == true
74 # assert [1..1[.not_empty == false
75 fun not_empty
: Bool do return not self.is_empty
77 # Number of items in the collection.
79 # assert [10,20,30].length == 3
80 # assert [20..30[.length == 10
84 for i
in self do nb
+= 1
88 # Is `item` in the collection ?
89 # Comparisons are done with ==
91 # assert [1,2,3].has(2) == true
92 # assert [1,2,3].has(9) == false
93 # assert [1..5[.has(2) == true
94 # assert [1..5[.has(9) == false
95 fun has
(item
: nullable Object): Bool
97 for i
in self do if i
== item
then return true
101 # Is the collection contain only `item`?
102 # Comparisons are done with ==
103 # Return true if the collection is empty.
105 # assert [1,1,1].has_only(1) == true
106 # assert [1,2,3].has_only(1) == false
107 # assert [1..1].has_only(1) == true
108 # assert [1..3].has_only(1) == false
109 # assert [3..3[.has_only(1) == true # empty collection
111 # ENSURE `is_empty implies result == true`
112 fun has_only
(item
: nullable Object): Bool
114 for i
in self do if i
!= item
then return false
118 # How many occurrences of `item` are in the collection?
119 # Comparisons are done with ==
121 # assert [10,20,10].count(10) == 2
122 fun count
(item
: nullable Object): Int
125 for i
in self do if i
== item
then nb
+= 1
129 # Return the first item of the collection
131 # assert [1,2,3].first == 1
138 # Does the collection contain at least each element of `other`?
140 # assert [1,3,4,2].has_all([1..2]) == true
141 # assert [1,3,4,2].has_all([1..5]) == false
143 # Repeated elements in the collections are not considered.
145 # assert [1,1,1].has_all([1]) == true
146 # assert [1..5].has_all([1,1,1]) == true
148 # Note that the default implementation is general and correct for any lawful Collections.
149 # It is memory-efficient but relies on `has` so may be CPU-inefficient for some kind of collections.
150 fun has_all
(other
: Collection[nullable Object]): Bool
152 if is_same_instance
(other
) then return true
153 var ol
= other
.length
155 if ol
== 0 then return true
156 if l
== 0 then return false
157 if ol
== 1 then return has
(other
.first
)
158 for x
in other
do if not has
(x
) then return false
162 # Does the collection contain exactly all the elements of `other`?
164 # The same elements must be present in both `self` and `other`,
165 # but the order of the elements in the collections are not considered.
167 # assert [1..3].has_exactly([3,1,2]) == true # the same elements
168 # assert [1..3].has_exactly([3,1]) == false # 2 is not in the array
169 # assert [1..2].has_exactly([3,1,2]) == false # 3 is not in the range
171 # Repeated elements must be present in both collections in the same amount.
172 # So basically it is a multi-set comparison.
174 # assert [1,2,3,2].has_exactly([1,2,2,3]) == true # the same elements
175 # assert [1,2,3,2].has_exactly([1,2,3]) == false # more 2 in the first array
176 # assert [1,2,3].has_exactly([1,2,2,3]) == false # more 2 in the second array
178 # Note that the default implementation is general and correct for any lawful Collections.
179 # It is memory-efficient but relies on `count` so may be CPU-inefficient for some kind of collections.
180 fun has_exactly
(other
: Collection[nullable Object]): Bool
182 if length
!= other
.length
then return false
183 for e
in self do if self.count
(e
) != other
.count
(e
) then return false
187 # Does the collection contain at least one element of `other`?
189 # assert [1,3,4,2].has_any([1..10]) == true
190 # assert [1,3,4,2].has_any([5..10]) == false
192 # Note that the default implementation is general and correct for any lawful Collections.
193 # It is memory-efficient but relies on `has` so may be CPU-inefficient for some kind of collections.
194 fun has_any
(other
: Collection[nullable Object]): Bool
197 if has
(o
) then return true
203 # Iterators generate a series of elements, one at a time.
205 # They are mainly used with collections and obtained from `Collection::iterator`.
206 interface Iterator[E
]
209 fun item
: E
is abstract
211 # Jump to the next item.
215 # Jump to the next item `step` times.
218 # var i = [11, 22, 33, 44].iterator
219 # assert i.item == 11
221 # assert i.item == 33
224 # `next_by` should be used instead of looping on `next` because is takes care
225 # of stopping if the end of iteration is reached prematurely whereas a loop of
226 # `next` will abort because of the precondition on `is_ok`.
233 # If `step` is negative, this method aborts.
234 # But specific subclasses can change this and do something more meaningful instead.
237 fun next_by
(step
: Int)
240 while is_ok
and step
> 0 do
246 # Is there a current item ?
247 fun is_ok
: Bool is abstract
249 # Iterate over `self`
250 fun iterator
: Iterator[E
] do return self
252 # Pre-iteration hook.
254 # Used to inform `self` that the iteration is starting.
255 # Specific iterators can use this to prepare some resources.
257 # Is automatically invoked at the beginning of `for` structures.
259 # Do nothing by default.
262 # Post-iteration hook.
264 # Used to inform `self` that the iteration is over.
265 # Specific iterators can use this to free some resources.
267 # Is automatically invoked at the end of `for` structures.
269 # Do nothing by default.
272 # A decorator around `self` that advance self a given number of steps instead of one.
275 # var i = [11, 22, 33, 44, 55].iterator
276 # var i2 = i.to_step(2)
278 # assert i2.item == 11
280 # assert i2.item == 33
282 # assert i.item == 33
284 fun to_step
(step
: Int): Iterator[E
] do return new StepIterator[E
](self, step
)
287 # A basic helper class to specialize specific Iterator decorators
288 abstract class IteratorDecorator[E
]
291 # The underling iterator
292 protected var real
: Iterator[E
]
294 redef fun is_ok
do return real
.is_ok
295 redef fun item
do return real
.item
296 redef fun finish
do real
.finish
297 redef fun next
do real
.next
298 redef fun next_by
(step
) do real
.next_by
(step
)
301 # A decorator that advance a given number of steps
302 private class StepIterator[E
]
303 super IteratorDecorator[E
]
306 redef fun next
do real
.next_by
(step
)
307 redef fun next_by
(step
) do real
.next_by
(step
* self.step
)
310 # A collection that contains only one item.
312 # Used to pass arguments by reference.
314 # Also used when one want to give a single element when a full
315 # collection is expected
319 redef fun first
do return item
321 redef fun is_empty
do return false
323 redef fun length
do return 1
325 redef fun has
(an_item
) do return item
== an_item
327 redef fun has_only
(an_item
) do return item
== an_item
329 redef fun count
(an_item
)
331 if item
== an_item
then
338 redef fun iterator
do return new RefIterator[E
](self)
341 var item
: E
is writable
344 # This iterator is quite stupid since it is used for only one item.
345 private class RefIterator[E
]
347 redef fun item
do return _container
.item
349 redef fun next
do is_ok
= false
351 redef var is_ok
= true
353 var container
: Ref[E
]
356 # Items can be removed from this collection
357 interface RemovableCollection[E
]
364 # assert a.length == 0
367 fun clear
is abstract
369 # Remove an occurrence of `item`
371 # var a = [1,2,3,1,2,3]
373 # assert a == [1,3,1,2,3]
374 fun remove
(item
: nullable Object) is abstract
376 # Remove all occurrences of `item`
378 # var a = [1,2,3,1,2,3]
380 # assert a == [1,3,1,3]
381 fun remove_all
(item
: nullable Object) do while has
(item
) do remove
(item
)
384 # Items can be added to these collections.
385 interface SimpleCollection[E
]
386 super RemovableCollection[E
]
388 # Add an item in a collection.
392 # assert a.has(3) == true
393 # assert a.has(10) == false
395 # Ensure col.has(item)
396 fun add
(item
: E
) is abstract
398 # Add each item of `coll`.
401 # assert a.has(4) == true
402 # assert a.has(10) == false
403 fun add_all
(coll
: Collection[E
]) do for i
in coll
do add
(i
)
408 # Set is a collection without duplicates (according to `==`)
410 # var s: Set[String] = new ArraySet[String]
412 # var b = "Hel" + "lo"
415 # assert s.has(b) == true
417 super SimpleCollection[E
]
420 redef fun has_only
(item
)
433 redef fun count
(item
)
442 # Synonym of remove since there is only one item
443 redef fun remove_all
(item
) do remove
(item
)
445 # Equality is defined on set and means that each set contains the same elements
448 if not other
isa Set[nullable Object] then return false
449 if other
.length
!= length
then return false
450 return has_all
(other
)
453 # Because of the law between `==` and `hash`, `hash` is redefined to be the sum of the hash of the elements
456 # 23 is a magic number empirically determined to be not so bad.
457 var res
= 23 + length
458 # Note: the order of the elements must not change the hash value.
459 # So, unlike usual hash functions, the accumulator is not combined with itself.
460 for e
in self do res
+= e
.hash
464 # Returns the union of this set with the `other` set
465 fun union
(other
: Set[E
]): Set[E
]
473 # Returns the intersection of this set with the `other` set
474 fun intersection
(other
: Set[E
]): Set[E
]
477 for v
in self do if other
.has
(v
) then nhs
.add
(v
)
481 redef fun clone
do return union
(self)
483 # Returns a new instance of `Set`.
485 # Depends on the subclass, mainly used for copy services
486 # like `union` or `intersection`.
487 protected fun new_set
: Set[E
] is abstract
490 # MapRead are abstract associative collections: `key` -> `item`.
491 interface MapRead[K
, V
]
492 # Get the item at `key`
494 # var x = new HashMap[String, Int]
496 # assert x["four"] == 4
497 # # assert x["five"] #=> abort
499 # If the key is not in the map, `provide_default_value` is called (that aborts by default)
500 # See `get_or_null` and `get_or_default` for safe variations.
501 fun [](key
: nullable Object): V
is abstract
503 # Get the item at `key` or null if `key` is not in the map.
505 # var x = new HashMap[String, Int]
507 # assert x.get_or_null("four") == 4
508 # assert x.get_or_null("five") == null
510 # Note: use `has_key` and `[]` if you need the distinction between a key associated with null, and no key.
511 fun get_or_null
(key
: nullable Object): nullable V
513 if has_key
(key
) then return self[key
]
517 # Get the item at `key` or return `default` if not in map
519 # var x = new HashMap[String, Int]
521 # assert x.get_or_default("four", 40) == 4
522 # assert x.get_or_default("five", 50) == 50
524 fun get_or_default
(key
: nullable Object, default
: V
): V
526 if has_key
(key
) then return self[key
]
530 # Is there an item associated with `key`?
532 # var x = new HashMap[String, Int]
534 # assert x.has_key("four") == true
535 # assert x.has_key("five") == false
537 # By default it is a synonymous to `keys.has` but could be redefined with a direct implementation.
538 fun has_key
(key
: nullable Object): Bool do return self.keys
.has
(key
)
540 # Get a new iterator on the map.
541 fun iterator
: MapIterator[K
, V
] is abstract
543 # Return the point of view of self on the values only.
544 # Note that `self` and `values` are views on the same data;
545 # therefore any modification of one is visible on the other.
547 # var x = new HashMap[String, Int]
549 # assert x.values.has(4) == true
550 # assert x.values.has(5) == false
551 fun values
: Collection[V
] is abstract
553 # Return the point of view of self on the keys only.
554 # Note that `self` and `keys` are views on the same data;
555 # therefore any modification of one is visible on the other.
557 # var x = new HashMap[String, Int]
559 # assert x.keys.has("four") == true
560 # assert x.keys.has("five") == false
561 fun keys
: Collection[K
] is abstract
563 # Is there no item in the collection?
565 # var x = new HashMap[String, Int]
566 # assert x.is_empty == true
568 # assert x.is_empty == false
569 fun is_empty
: Bool is abstract
571 # Alias for `not is_empty`.
573 # Some people prefer to have conditions grammatically easier to read.
575 # var map = new HashMap[String, Int]
576 # assert map.not_empty == false
578 # assert map.not_empty == true
579 fun not_empty
: Bool do return not self.is_empty
581 # Number of items in the collection.
583 # var x = new HashMap[String, Int]
584 # assert x.length == 0
586 # assert x.length == 1
588 # assert x.length == 2
589 fun length
: Int is abstract
591 # Called by the underling implementation of `[]` to provide a default value when a `key` has no value
592 # By default the behavior is to abort.
594 # Note: the value is returned *as is*, implementations may want to store the value in the map before returning it
596 protected fun provide_default_value
(key
: nullable Object): V
do abort
598 # Does `self` and `other` have the same keys associated with the same values?
601 # var a = new HashMap[String, Int]
602 # var b = new ArrayMap[Object, Numeric]
613 if not other
isa MapRead[nullable Object, nullable Object] then return false
614 if other
.length
!= self.length
then return false
616 if not other
.has_key
(k
) then return false
617 if other
[k
] != v
then return false
622 # A hashcode based on the hashcode of the keys and the values.
625 # var a = new HashMap[String, Int]
626 # var b = new ArrayMap[Object, Numeric]
629 # assert a.hash == b.hash
635 if k
!= null then res
+= k
.hash
* 7
636 if v
!= null then res
+= v
.hash
* 11
642 # Maps are associative collections: `key` -> `item`.
644 # The main operator over maps is [].
646 # var map: Map[String, Int] = new ArrayMap[String, Int]
648 # map["one"] = 1 # Associate 'one' to '1'
649 # map["two"] = 2 # Associate 'two' to '2'
650 # assert map["one"] == 1
651 # assert map["two"] == 2
653 # Instances of maps can be used with the for structure
655 # for key, value in map do
656 # assert (key == "one" and value == 1) or (key == "two" and value == 2)
659 # The keys and values in the map can also be manipulated directly with the `keys` and `values` methods.
661 # assert map.keys.has("one") == true
662 # assert map.keys.has("tree") == false
663 # assert map.values.has(1) == true
664 # assert map.values.has(3) == false
669 # Set the `value` at `key`.
671 # Values can then get retrieved with `[]`.
673 # var x = new HashMap[String, Int]
675 # assert x["four"] == 4
677 # If the key was associated with a value, this old value is discarded
678 # and replaced with the new one.
681 # assert x["four"] == 40
682 # assert x.values.has(4) == false
684 fun []=(key
: K
, value
: V
) is abstract
686 # Add each (key,value) of `map` into `self`.
687 # If a same key exists in `map` and `self`, then the value in self is discarded.
689 # var x = new HashMap[String, Int]
692 # var y = new HashMap[String, Int]
696 # assert x["four"] == 40
697 # assert x["five"] == 5
698 # assert x["nine"] == 90
699 fun add_all
(map
: MapRead[K
, V
])
708 # Alias for `add_all`
709 fun recover_with
(map
: MapRead[K
, V
]) is deprecated
do add_all
(map
)
713 # var x = new HashMap[String, Int]
716 # assert x.keys.has("four") == false
719 fun clear
is abstract
721 redef fun values
: RemovableCollection[V
] is abstract
723 redef fun keys
: RemovableCollection[K
] is abstract
727 interface MapIterator[K
, V
]
730 fun item
: V
is abstract
732 # The key of the current item.
734 fun key
: K
is abstract
736 # Jump to the next item.
740 # Is there a current item ?
741 fun is_ok
: Bool is abstract
743 # Set a new `item` at `key`.
744 #fun item=(item: E) is abstract
746 # Pre-iteration hook.
748 # Used to inform `self` that the iteration is starting.
749 # Specific iterators can use this to prepare some resources.
751 # Is automatically invoked at the beginning of `for` structures.
753 # Do nothing by default.
756 # Post-iteration hook.
758 # Used to inform `self` that the iteration is over.
759 # Specific iterators can use this to free some resources.
761 # Is automatically invoked at the end of `for` structures.
763 # Do nothing by default.
767 # Iterator on a 'keys' point of view of a map
768 class MapKeysIterator[K
, V
]
770 # The original iterator
771 var original_iterator
: MapIterator[K
, V
]
773 redef fun is_ok
do return self.original_iterator
.is_ok
774 redef fun next
do self.original_iterator
.next
775 redef fun item
do return self.original_iterator
.key
778 # Iterator on a 'values' point of view of a map
779 class MapValuesIterator[K
, V
]
781 # The original iterator
782 var original_iterator
: MapIterator[K
, V
]
784 redef fun is_ok
do return self.original_iterator
.is_ok
785 redef fun next
do self.original_iterator
.next
786 redef fun item
do return self.original_iterator
.item
789 # Sequences are indexed collections.
790 # The first item is 0. The last is `length-1`.
792 # The order is the main caracteristic of sequence
793 # and all concrete implementation of sequences are basically interchangeable.
794 interface SequenceRead[E
]
797 # Get the first item.
798 # Is equivalent with `self[0]`.
801 # assert a.first == 1
803 # REQUIRE `not is_empty`
806 assert not_empty
: not is_empty
810 # Return the index-th element of the sequence.
811 # The first element is 0 and the last is `length-1`
812 # If index is invalid, the program aborts
819 # REQUIRE `index >= 0 and index < length`
820 fun [](index
: Int): E
is abstract
822 # Return the index-th element but wrap
824 # Whereas `self[]` requires the index to exists, the `modulo` accessor automatically
825 # wraps overbound and underbouds indexes.
829 # assert a.modulo(1) == 20
830 # assert a.modulo(3) == 10
831 # assert a.modulo(-1) == 30
832 # assert a.modulo(-10) == 30
835 # REQUIRE `not_empty`
836 # ENSURE `result == self[modulo_index(index)]`
837 fun modulo
(index
: Int): E
do return self[modulo_index
(index
)]
839 # Returns the real index for a modulo index.
843 # assert a.modulo_index(1) == 1
844 # assert a.modulo_index(3) == 0
845 # assert a.modulo_index(-1) == 2
846 # assert a.modulo_index(-10) == 2
849 # REQUIRE `not_empty`
850 fun modulo_index
(index
: Int): Int
852 var length
= self.length
854 return index
% length
856 return length
- (-1 - index
) % length
- 1
861 # Is equivalent with `self[length-1]`.
866 # REQUIRE `not is_empty`
869 assert not_empty
: not is_empty
870 return self[length-1
]
873 # The index of the first occurrence of `item`.
874 # Return -1 if `item` is not found.
875 # Comparison is done with `==`.
877 # var a = [10,20,30,10,20,30]
878 # assert a.index_of(20) == 1
879 # assert a.index_of(40) == -1
880 fun index_of
(item
: nullable Object): Int do return index_of_from
(item
, 0)
882 # The index of the last occurrence of `item`.
883 # Return -1 if `item` is not found.
884 # Comparison is done with `==`.
886 # var a = [10,20,30,10,20,30]
887 # assert a.last_index_of(20) == 4
888 # assert a.last_index_of(40) == -1
889 fun last_index_of
(item
: nullable Object): Int do return last_index_of_from
(item
, length-1
)
891 # The index of the first occurrence of `item`, starting from pos.
892 # Return -1 if `item` is not found.
893 # Comparison is done with `==`.
895 # var a = [10,20,30,10,20,30]
896 # assert a.index_of_from(20, 3) == 4
897 # assert a.index_of_from(20, 4) == 4
898 # assert a.index_of_from(20, 5) == -1
899 fun index_of_from
(item
: nullable Object, pos
: Int): Int
904 if p
>=pos
and i
.item
== item
then return i
.index
911 # The index of the last occurrence of `item` starting from `pos` and decrementing.
912 # Return -1 if `item` is not found.
913 # Comparison is done with `==`.
915 # var a = [10,20,30,10,20,30]
916 # assert a.last_index_of_from(20, 2) == 1
917 # assert a.last_index_of_from(20, 1) == 1
918 # assert a.last_index_of_from(20, 0) == -1
919 fun last_index_of_from
(item
: nullable Object, pos
: Int): Int do
922 if self[i
] == item
then return i
928 # Two sequences are equals if they have the same items in the same order.
930 # var a = new List[Int]
934 # assert a == [1,2,3]
935 # assert a != [1,3,2]
938 if not o
isa SequenceRead[nullable Object] then return false
940 if o
.length
!= l
then return false
943 if self[i
] != o
[i
] then return false
949 # Because of the law between `==` and `hash`, `hash` is redefined to be the sum of the hash of the elements
952 # The 17 and 2/3 magic numbers were determined empirically.
953 # Note: the standard hash functions djb2, sbdm and fnv1 were also
954 # tested but were comparable (or worse).
955 var res
= 17 + length
958 if e
!= null then res
+= e
.hash
963 redef fun iterator
: IndexedIterator[E
] is abstract
965 # Gets a new Iterator starting at position `pos`
967 # var iter = [10,20,30,40,50].iterator_from(2)
968 # assert iter.to_a == [30, 40, 50]
969 fun iterator_from
(pos
: Int): IndexedIterator[E
]
972 while pos
> 0 and res
.is_ok
do
979 # Gets an iterator starting at the end and going backwards
981 # var reviter = [1,2,3].reverse_iterator
982 # assert reviter.to_a == [3,2,1]
983 fun reverse_iterator
: IndexedIterator[E
] is abstract
985 # Gets an iterator on the chars of self starting from `pos`
987 # var reviter = [10,20,30,40,50].reverse_iterator_from(2)
988 # assert reviter.to_a == [30,20,10]
989 fun reverse_iterator_from
(pos
: Int): IndexedIterator[E
]
991 var res
= reverse_iterator
992 while pos
> 0 and res
.is_ok
do
1000 # Sequence are indexed collection.
1001 # The first item is 0. The last is `length-1`.
1002 interface Sequence[E
]
1003 super SequenceRead[E
]
1004 super SimpleCollection[E
]
1006 # Set the first item.
1007 # Is equivalent with `self[0] = item`.
1011 # assert a == [10,2,3]
1013 do self[0] = item
end
1015 # Set the last item.
1016 # Is equivalent with `self[length-1] = item`.
1020 # assert a == [1,2,10]
1022 # If the sequence is empty, `last=` is equivalent with `self[0]=` (thus with `first=`)
1024 # var b = new Array[Int]
1037 # A synonym of `push`
1038 redef fun add
(e
) do push
(e
)
1040 # Add an item after the last one.
1045 # assert a == [1,2,3,10,20]
1046 fun push
(e
: E
) is abstract
1048 # Add each item of `coll` after the last.
1052 # assert a == [1,2,3,7,8,9]
1054 # Alias of `add_all`
1055 fun append
(coll
: Collection[E
]) do add_all
(coll
)
1057 # Remove the last item.
1064 # REQUIRE `not is_empty`
1065 fun pop
: E
is abstract
1067 # Add an item before the first one.
1072 # assert a == [20,10,1,2,3]
1073 fun unshift
(e
: E
) is abstract
1075 # Add all items of `coll` before the first one.
1079 # assert a == [7,8,9,1,2,3]
1081 # Alias of `insert_at(coll, 0)`
1082 fun prepend
(coll
: Collection[E
]) do insert_all
(coll
, 0)
1084 # Remove the first item.
1085 # The second item thus become the first.
1088 # assert a.shift == 1
1089 # assert a.shift == 2
1092 # REQUIRE `not is_empty`
1093 fun shift
: E
is abstract
1095 # Set the `item` at `index`.
1097 # var a = [10,20,30]
1099 # assert a == [10,200,30]
1101 # like with `[]`, index should be between `0` and `length-1`
1102 # However, if `index==length`, `[]=` works like `push`.
1105 # assert a == [10,200,30,400]
1107 # REQUIRE `index >= 0 and index <= length`
1108 fun []=(index
: Int, item
: E
) is abstract
1110 # Set the index-th element but wrap
1112 # Whereas `self[]=` requires the index to exists, the `modulo` accessor automatically
1113 # wraps overbound and underbouds indexes.
1116 # var a = [10,20,30]
1119 # a.modulo(-1) = 300
1120 # a.modulo(-10) = 301
1121 # assert a == [100, 200, 301]
1124 # REQUIRE `not_empty`
1125 # ENSURE `self[modulo_index(index)] == value`
1126 fun modulo
=(index
: Int, value
: E
) do self[modulo_index
(index
)] = value
1128 # Insert an element at a given position, following elements are shifted.
1130 # var a = [10, 20, 30, 40]
1132 # assert a == [10, 20, 100, 30, 40]
1134 # REQUIRE `index >= 0 and index <= length`
1135 # ENSURE `self[index] == item`
1136 fun insert
(item
: E
, index
: Int) is abstract
1138 # Insert all elements at a given position, following elements are shifted.
1140 # var a = [10, 20, 30, 40]
1141 # a.insert_all([100..102], 2)
1142 # assert a == [10, 20, 100, 101, 102, 30, 40]
1144 # REQUIRE `index >= 0 and index <= length`
1145 # ENSURE `self[index] == coll.first`
1146 fun insert_all
(coll
: Collection[E
], index
: Int)
1148 assert index
>= 0 and index
< length
1149 if index
== length
then
1158 # Remove the item at `index` and shift all following elements
1160 # var a = [10,20,30]
1162 # assert a == [10,30]
1164 # REQUIRE `index >= 0 and index < length`
1165 fun remove_at
(index
: Int) is abstract
1167 # Rotates the elements of self once to the left
1170 # var a = [12, 23, 34, 45]
1172 # assert a == [23, 34, 45, 12]
1179 # Rotates the elements of self once to the right
1182 # var a = [12, 23, 34, 45]
1184 # assert a == [45, 12, 23, 34]
1192 # Iterators on indexed collections.
1193 interface IndexedIterator[E
]
1195 # The index of the current item.
1196 fun index
: Int is abstract
1199 # Associative arrays that internally uses couples to represent each (key, value) pairs.
1200 # This is an helper class that some specific implementation of Map may implements.
1201 interface CoupleMap[K
, V
]
1204 # Return the couple of the corresponding key
1205 # Return null if the key is no associated element
1206 protected fun couple_at
(key
: nullable Object): nullable Couple[K
, V
] is abstract
1208 # Return a new iteralot on all couples
1209 # Used to provide `iterator` and others
1210 protected fun couple_iterator
: Iterator[Couple[K
,V
]] is abstract
1212 redef fun iterator
do return new CoupleMapIterator[K
,V
](couple_iterator
)
1216 var c
= couple_at
(key
)
1218 return provide_default_value
(key
)
1224 redef fun has_key
(key
) do return couple_at
(key
) != null
1227 # Iterator on CoupleMap
1229 # Actually it is a wrapper around an iterator of the internal array of the map.
1230 private class CoupleMapIterator[K
, V
]
1231 super MapIterator[K
, V
]
1232 redef fun item
do return _iter
.item
.second
1234 #redef fun item=(e) do _iter.item.second = e
1236 redef fun key
do return _iter
.item
.first
1238 redef fun is_ok
do return _iter
.is_ok
1245 var iter
: Iterator[Couple[K
,V
]]
1248 # Some tools ###################################################################
1250 # Two objects in a simple structure.
1253 # The first element of the couple.
1254 var first
: F
is writable
1256 # The second element of the couple.
1257 var second
: S
is writable