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 package 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?
57 fun is_empty
: Bool is abstract
59 # Number of items in the collection.
60 fun length
: Int is abstract
62 # Is `item` in the collection ?
63 # Comparisons are done with ==
64 fun has
(item
: E
): Bool is abstract
66 # Is the collection contain only `item`?
67 # Comparisons are done with ==
68 # Return true if the collection is empty.
69 fun has_only
(item
: E
): Bool is abstract
71 # How many occurrences of `item` are in the collection?
72 # Comparisons are done with ==
73 fun count
(item
: E
): Int is abstract
75 # Return one the item of the collection
76 fun first
: E
is abstract
79 # Naive implementation of collections method
80 # You only have to define iterator!
81 interface NaiveCollection[E
]
83 redef fun is_empty
do return length
== 0
88 for i
in self do nb
+= 1
94 for i
in self do if i
== item
then return true
98 redef fun has_only
(item
)
100 for i
in self do if i
!= item
then return false
104 redef fun count
(item
)
107 for i
in self do if i
== item
then nb
+= 1
118 # Instances of the Iterator class generates a series of elements, one at a time.
119 # They are mainly used with collections.
120 interface Iterator[E
]
123 fun item
: E
is abstract
125 # Jump to the next item.
129 # Is there a current item ?
130 fun is_ok
: Bool is abstract
133 # A collection that contains only one item.
137 redef fun first
do return _item
139 redef fun is_empty
do return false
141 redef fun length
do return 1
143 redef fun has
(an_item
) do return _item
== an_item
145 redef fun has_only
(an_item
) do return _item
== an_item
147 redef fun count
(an_item
)
149 if _item
== an_item
then
156 redef fun iterator
do return new ContainerIterator[E
](self)
158 # Create a new instance with a given initial value.
159 init(e
: E
) do _item
= e
162 readable writable var _item
: E
165 # This iterator is quite stupid since it is used for only one item.
166 class ContainerIterator[E
]
168 redef fun item
do return _container
.item
170 redef fun next
do _is_ok
= false
172 init(c
: Container[E
]) do _container
= c
174 redef readable var _is_ok
: Bool = true
176 var _container
: Container[E
]
179 # Items can be removed from this collection
180 interface RemovableCollection[E
]
183 fun clear
is abstract
185 # Remove an occucence of `item`
186 fun remove
(item
: E
) is abstract
188 # Remove all occurences of `item`
189 fun remove_all
(item
: E
) do while has
(item
) do remove
(item
)
192 # Items can be added to these collections.
193 interface SimpleCollection[E
]
194 super RemovableCollection[E
]
195 # Add an item in a collection.
196 # Ensure col.has(item)
197 fun add
(item
: E
) is abstract
199 # Add each item of `coll`.
200 fun add_all
(coll
: Collection[E
]) do for i
in coll
do add
(i
)
205 # Set contains contains only one element with the same value (according to ==).
208 # var b = "Hel" + "lo"
211 # s.has(b) # --> true
212 interface Set[E
: Object]
213 super SimpleCollection[E
]
215 redef fun has_only
(item
)
228 redef fun count
(item
)
237 # Synonym of remove since there is only one item
238 redef fun remove_all
(item
) do remove
(item
)
241 # MapRead are abstract associative collections: `key` -> `item`.
242 interface MapRead[K
: Object, E
]
243 # Get the item at `key`.
244 fun [](key
: K
): E
is abstract
246 # Depreciated alias for `keys.has`
247 fun has_key
(key
: K
): Bool do return self.keys
.has
(key
)
249 # Get a new iterator on the map.
250 fun iterator
: MapIterator[K
, E
] is abstract
252 # Iterate over each element of the collection
263 # Return the point of view of self on the values only.
264 # Note that `self` and `values` are views on the same data;
265 # therefore any modification of one is visible on the other.
266 fun values
: Collection[E
] is abstract
268 # Return the point of view of self on the keys only.
269 # Note that `self` and `keys` are views on the same data;
270 # therefore any modification of one is visible on the other.
271 fun keys
: Collection[K
] is abstract
273 # Is there no item in the collection?
274 fun is_empty
: Bool is abstract
276 # Number of items in the collection.
277 fun length
: Int is abstract
280 # Maps are associative collections: `key` -> `item`.
282 # The main operator over maps is [].
286 # map[u1] = v1 # Associate 'v1' to 'u1'
287 # map[u2] = v2 # Associate 'v2' to 'u2'
288 # print map[u1] # -> v1
289 # print map[u2] # -> v2
291 # Instances of maps can be used with the for structure
293 # for key, value in map do # things with `key` and `value`
295 # The keys and values in the map can also be manipulated directly with the `keys` and `values` methods.
297 # map.keys.has(u1) # -> true
298 # map.keys.has(u3) # -> false
299 # map.values.has(v1) # -> true
300 # map.values.has(v3) # -> false
302 interface Map[K
: Object, E
]
304 # Set the`item` at `key`.
305 fun []=(key
: K
, item
: E
) is abstract
307 # Add each (key,value) of `map` into `self`.
308 # If a same key exists in `map` and `self`, then the value in self is discarded.
309 fun recover_with
(map
: Map[K
, E
])
319 fun clear
is abstract
321 redef fun values
: RemovableCollection[E
] is abstract
323 redef fun keys
: RemovableCollection[K
] is abstract
327 interface MapIterator[K
: Object, E
]
330 fun item
: E
is abstract
332 # The key of the current item.
334 fun key
: K
is abstract
336 # Jump to the next item.
340 # Is there a current item ?
341 fun is_ok
: Bool is abstract
343 # Set a new `item` at `key`.
344 #fun item=(item: E) is abstract
347 # Iterator on a 'keys' point of view of a map
348 class MapKeysIterator[K
: Object, V
]
350 # The original iterator
351 var iterator
: MapIterator[K
, V
]
353 redef fun is_ok
do return self.iterator
.is_ok
354 redef fun next
do self.iterator
.next
355 redef fun item
do return self.iterator
.key
358 # Iterator on a 'values' point of view of a map
359 class MapValuesIterator[K
: Object, V
]
361 # The original iterator
362 var iterator
: MapIterator[K
, V
]
364 redef fun is_ok
do return self.iterator
.is_ok
365 redef fun next
do self.iterator
.next
366 redef fun item
do return self.iterator
.item
369 # Sequences are indexed collections.
370 # The first item is 0. The last is `length-1`.
371 interface SequenceRead[E
]
373 # Get the first item.
374 # Is equivalent with `self[0]`.
377 assert not_empty
: not is_empty
381 # Return the index=th element of the sequence.
382 # The first element is 0 and the last if `length-1`
383 # If index is invalid, the program aborts
384 fun [](index
: Int): E
is abstract
387 # Is equivalent with `self[length-1]`.
390 assert not_empty
: not is_empty
391 return self[length-1
]
394 # Return the index of the first occurrence of `item`.
395 # Return -1 if `item` is not found
396 # Comparison is done with ==
397 fun index_of
(item
: E
): Int
401 if i
.item
== item
then return i
.index
407 redef fun iterator
: IndexedIterator[E
] is abstract
410 # Sequence are indexed collection.
411 # The first item is 0. The last is `length-1`.
412 interface Sequence[E
]
413 super SequenceRead[E
]
414 super SimpleCollection[E
]
416 # Set the first item.
417 # Is equivalent with `self[0] = item`.
419 do self[0] = item
end
422 # Is equivalent with `self[length-1] = item`.
433 # A synonym of `push`
434 redef fun add
(e
) do push
(e
)
436 # Add an item after the last.
437 fun push
(e
: E
) is abstract
439 # Add each item of `coll` after the last.
440 fun append
(coll
: Collection[E
]) do for i
in coll
do push
(i
)
442 # Remove the last item.
443 fun pop
: E
is abstract
445 # Add an item before the last.
446 fun unshift
(e
: E
) is abstract
448 # Remove the first item.
449 # The second item become the first.
450 fun shift
: E
is abstract
452 # Set the `item` at `index`.
453 fun []=(index
: Int, item
: E
) is abstract
455 # Remove the item at `index` and shift all following elements
456 fun remove_at
(index
: Int) is abstract
459 # Iterators on indexed collections.
460 interface IndexedIterator[E
]
462 # The index of the current item.
463 fun index
: Int is abstract
466 # Associative arrays that internally uses couples to represent each (key, value) pairs.
467 interface CoupleMap[K
: Object, E
]
469 # Return the couple of the corresponding key
470 # Return null if the key is no associated element
471 protected fun couple_at
(key
: K
): nullable Couple[K
, E
] is abstract
475 var c
= couple_at
(key
)
484 # Iterator on CoupleMap
486 # Actually is is a wrapper around an iterator of the internal array of the map.
487 class CoupleMapIterator[K
: Object, E
]
488 super MapIterator[K
, E
]
489 redef fun item
do return _iter
.item
.second
491 #redef fun item=(e) do _iter.item.second = e
493 redef fun key
do return _iter
.item
.first
495 redef fun is_ok
do return _iter
.is_ok
502 var _iter
: Iterator[Couple[K
,E
]]
504 init(i
: Iterator[Couple[K
,E
]]) do _iter
= i
507 # Some tools ###################################################################
509 # Two objects in a simple structure.
512 # The first element of the couple.
513 readable writable var _first
: F
515 # The second element of the couple.
516 readable writable var _second
: S
518 # Create a new instance with a first and a second object.