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 # This module define several abstract collection classes.
14 module abstract_collection
18 # The root of the collection hierarchy.
20 # Instances of this class offers an iterator method.
22 # Collections instances can use the "for" structure:
23 # var x: Collection[U]
29 # that is equivalent with
30 # var x: Collection[U]
34 # var u = i.item # u is a U
39 # This abstract class implements its others methods with an iterator.
40 # Subclasses may redefine them with an efficient implementation.
41 interface Collection[E
]
42 # Get a new iterator on the collection.
43 fun iterator
: Iterator[E
] is abstract
45 # Iterate over each element of the collection
56 # Is there no item in the collection?
58 # assert [1,2,3].is_empty == false
59 # assert [1..1[.is_empty == true
60 fun is_empty
: Bool do return length
== 0
62 # Number of items in the collection.
64 # assert [10,20,30].length == 3
65 # assert [20..30[.length == 10
69 for i
in self do nb
+= 1
74 # Is `item` in the collection ?
75 # Comparisons are done with ==
77 # assert [1,2,3].has(2) == true
78 # assert [1,2,3].has(9) == false
79 # assert [1..5[.has(2) == true
80 # assert [1..5[.has(9) == false
81 fun has
(item
: E
): Bool
83 for i
in self do if i
== item
then return true
87 # Is the collection contain only `item`?
88 # Comparisons are done with ==
89 # Return true if the collection is empty.
91 # assert [1,1,1].has_only(1) == true
92 # assert [1,2,3].has_only(1) == false
93 # assert [1..1].has_only(1) == true
94 # assert [1..3].has_only(1) == false
95 # assert [3..3[.has_only(1) == true # empty collection
97 # ENSURE `is_empty implies result == true`
98 fun has_only
(item
: E
): Bool
100 for i
in self do if i
!= item
then return false
104 # How many occurrences of `item` are in the collection?
105 # Comparisons are done with ==
107 # assert [10,20,10].count(10) == 2
108 fun count
(item
: E
): Int
111 for i
in self do if i
== item
then nb
+= 1
115 # Return one the item of the collection
117 # assert [1,2,3].first == 1
124 # Is the collection contains all the elements of `other`?
126 # assert [1,1,1].has_all([1]) == true
127 # assert [1,1,1].has_all([1,2]) == false
128 # assert [1,3,4,2].has_all([1..2]) == true
129 # assert [1,3,4,2].has_all([1..5]) == false
130 fun has_all
(other
: Collection[E
]): Bool
132 for x
in other
do if not has
(x
) then return false
137 # Naive implementation of collections method
138 # You only have to define iterator!
139 interface NaiveCollection[E
]
143 # Instances of the Iterator class generates a series of elements, one at a time.
144 # They are mainly used with collections.
145 interface Iterator[E
]
148 fun item
: E
is abstract
150 # Jump to the next item.
154 # Is there a current item ?
155 fun is_ok
: Bool is abstract
158 # A collection that contains only one item.
162 redef fun first
do return _item
164 redef fun is_empty
do return false
166 redef fun length
do return 1
168 redef fun has
(an_item
) do return _item
== an_item
170 redef fun has_only
(an_item
) do return _item
== an_item
172 redef fun count
(an_item
)
174 if _item
== an_item
then
181 redef fun iterator
do return new ContainerIterator[E
](self)
183 # Create a new instance with a given initial value.
184 init(e
: E
) do _item
= e
187 readable writable var _item
: E
190 # This iterator is quite stupid since it is used for only one item.
191 class ContainerIterator[E
]
193 redef fun item
do return _container
.item
195 redef fun next
do _is_ok
= false
197 init(c
: Container[E
]) do _container
= c
199 redef readable var _is_ok
: Bool = true
201 var _container
: Container[E
]
204 # Items can be removed from this collection
205 interface RemovableCollection[E
]
208 fun clear
is abstract
210 # Remove an occucence of `item`
211 fun remove
(item
: E
) is abstract
213 # Remove all occurences of `item`
214 fun remove_all
(item
: E
) do while has
(item
) do remove
(item
)
217 # Items can be added to these collections.
218 interface SimpleCollection[E
]
219 super RemovableCollection[E
]
220 # Add an item in a collection.
221 # Ensure col.has(item)
222 fun add
(item
: E
) is abstract
224 # Add each item of `coll`.
225 fun add_all
(coll
: Collection[E
]) do for i
in coll
do add
(i
)
230 # Set contains contains only one element with the same value (according to ==).
231 # var s: Set[String] = new ArraySet[String]
233 # var b = "Hel" + "lo"
236 # assert s.has(b) == true
237 interface Set[E
: Object]
238 super SimpleCollection[E
]
240 redef fun has_only
(item
)
253 redef fun count
(item
)
262 # Synonym of remove since there is only one item
263 redef fun remove_all
(item
) do remove
(item
)
265 # Equality is defined on set and means that each set contains the same elements
268 if not other
isa Set[Object] then return false
269 if other
.length
!= length
then return false
270 return has_all
(other
)
274 # MapRead are abstract associative collections: `key` -> `item`.
275 interface MapRead[K
: Object, E
]
276 # Get the item at `key`.
277 fun [](key
: K
): E
is abstract
279 # Get the item at `key` or return `default` if not in map
280 fun get_or_default
(key
: K
, default
: E
): E
282 if has_key
(key
) then return self[key
]
286 # Depreciated alias for `keys.has`
287 fun has_key
(key
: K
): Bool do return self.keys
.has
(key
)
289 # Get a new iterator on the map.
290 fun iterator
: MapIterator[K
, E
] is abstract
292 # Iterate over each element of the collection
303 # Return the point of view of self on the values only.
304 # Note that `self` and `values` are views on the same data;
305 # therefore any modification of one is visible on the other.
306 fun values
: Collection[E
] is abstract
308 # Return the point of view of self on the keys only.
309 # Note that `self` and `keys` are views on the same data;
310 # therefore any modification of one is visible on the other.
311 fun keys
: Collection[K
] is abstract
313 # Is there no item in the collection?
314 fun is_empty
: Bool is abstract
316 # Number of items in the collection.
317 fun length
: Int is abstract
320 # Maps are associative collections: `key` -> `item`.
322 # The main operator over maps is [].
324 # var map: Map[String, Int] = new ArrayMap[String, Int]
326 # map["one"] = 1 # Associate 'one' to '1'
327 # map["two"] = 2 # Associate 'two' to '2'
328 # assert map["one"] == 1
329 # assert map["two"] == 2
331 # Instances of maps can be used with the for structure
333 # for key, value in map do
334 # assert (key == "one" and value == 1) or (key == "two" and value == 2)
337 # The keys and values in the map can also be manipulated directly with the `keys` and `values` methods.
339 # assert map.keys.has("one") == true
340 # assert map.keys.has("tree") == false
341 # assert map.values.has(1) == true
342 # assert map.values.has(3) == false
344 interface Map[K
: Object, E
]
346 # Set the`item` at `key`.
347 fun []=(key
: K
, item
: E
) is abstract
349 # Add each (key,value) of `map` into `self`.
350 # If a same key exists in `map` and `self`, then the value in self is discarded.
351 fun recover_with
(map
: Map[K
, E
])
361 fun clear
is abstract
363 redef fun values
: RemovableCollection[E
] is abstract
365 redef fun keys
: RemovableCollection[K
] is abstract
369 interface MapIterator[K
: Object, E
]
372 fun item
: E
is abstract
374 # The key of the current item.
376 fun key
: K
is abstract
378 # Jump to the next item.
382 # Is there a current item ?
383 fun is_ok
: Bool is abstract
385 # Set a new `item` at `key`.
386 #fun item=(item: E) is abstract
389 # Iterator on a 'keys' point of view of a map
390 class MapKeysIterator[K
: Object, V
]
392 # The original iterator
393 var iterator
: MapIterator[K
, V
]
395 redef fun is_ok
do return self.iterator
.is_ok
396 redef fun next
do self.iterator
.next
397 redef fun item
do return self.iterator
.key
400 # Iterator on a 'values' point of view of a map
401 class MapValuesIterator[K
: Object, V
]
403 # The original iterator
404 var iterator
: MapIterator[K
, V
]
406 redef fun is_ok
do return self.iterator
.is_ok
407 redef fun next
do self.iterator
.next
408 redef fun item
do return self.iterator
.item
411 # Sequences are indexed collections.
412 # The first item is 0. The last is `length-1`.
413 interface SequenceRead[E
]
415 # Get the first item.
416 # Is equivalent with `self[0]`.
419 assert not_empty
: not is_empty
423 # Return the index=th element of the sequence.
424 # The first element is 0 and the last if `length-1`
425 # If index is invalid, the program aborts
426 fun [](index
: Int): E
is abstract
429 # Is equivalent with `self[length-1]`.
432 assert not_empty
: not is_empty
433 return self[length-1
]
436 # Return the index of the first occurrence of `item`.
437 # Return -1 if `item` is not found
438 # Comparison is done with ==
439 fun index_of
(item
: E
): Int
443 if i
.item
== item
then return i
.index
449 redef fun iterator
: IndexedIterator[E
] is abstract
452 # Sequence are indexed collection.
453 # The first item is 0. The last is `length-1`.
454 interface Sequence[E
]
455 super SequenceRead[E
]
456 super SimpleCollection[E
]
458 # Set the first item.
459 # Is equivalent with `self[0] = item`.
461 do self[0] = item
end
464 # Is equivalent with `self[length-1] = item`.
475 # A synonym of `push`
476 redef fun add
(e
) do push
(e
)
478 # Add an item after the last.
479 fun push
(e
: E
) is abstract
481 # Add each item of `coll` after the last.
482 fun append
(coll
: Collection[E
]) do for i
in coll
do push
(i
)
484 # Remove the last item.
485 fun pop
: E
is abstract
487 # Add an item before the last.
488 fun unshift
(e
: E
) is abstract
490 # Remove the first item.
491 # The second item become the first.
492 fun shift
: E
is abstract
494 # Set the `item` at `index`.
495 fun []=(index
: Int, item
: E
) is abstract
497 # Remove the item at `index` and shift all following elements
498 fun remove_at
(index
: Int) is abstract
501 # Iterators on indexed collections.
502 interface IndexedIterator[E
]
504 # The index of the current item.
505 fun index
: Int is abstract
508 # Associative arrays that internally uses couples to represent each (key, value) pairs.
509 interface CoupleMap[K
: Object, E
]
511 # Return the couple of the corresponding key
512 # Return null if the key is no associated element
513 protected fun couple_at
(key
: K
): nullable Couple[K
, E
] is abstract
517 var c
= couple_at
(key
)
526 # Iterator on CoupleMap
528 # Actually is is a wrapper around an iterator of the internal array of the map.
529 class CoupleMapIterator[K
: Object, E
]
530 super MapIterator[K
, E
]
531 redef fun item
do return _iter
.item
.second
533 #redef fun item=(e) do _iter.item.second = e
535 redef fun key
do return _iter
.item
.first
537 redef fun is_ok
do return _iter
.is_ok
544 var _iter
: Iterator[Couple[K
,E
]]
546 init(i
: Iterator[Couple[K
,E
]]) do _iter
= i
549 # Some tools ###################################################################
551 # Two objects in a simple structure.
554 # The first element of the couple.
555 readable writable var _first
: F
557 # The second element of the couple.
558 readable writable var _second
: S
560 # Create a new instance with a first and a second object.