1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Licensed under the Apache License, Version 2.0 (the "License");
4 # you may not use this file except in compliance with the License.
5 # You may obtain a copy of the License at
7 # http://www.apache.org/licenses/LICENSE-2.0
9 # Unless required by applicable law or agreed to in writing, software
10 # distributed under the License is distributed on an "AS IS" BASIS,
11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 # See the License for the specific language governing permissions and
13 # limitations under the License.
15 # Highly specific, but useful, collections-related classes.
16 module more_collections
18 # Simple way to store an `HashMap[K, Array[V]]`
20 # Unlike standard HashMap, MultiHashMap provides a new
21 # empty array on the first access on a unknown key.
23 # var m = new MultiHashMap[String, Char]
24 # assert not m.has_key("four")
29 # assert m.has_key("four")
30 # assert m["four"] == ['i', 'i', 'i', 'i']
31 # assert m["zzz"] == new Array[Char]
32 class MultiHashMap[K
, V
]
33 super HashMap[K
, Array[V
]]
35 # Add `v` to the array associated with `k`.
36 # If there is no array associated, then create it.
37 fun add_one
(k
: K
, v
: V
)
39 if self.has_key
(k
) then
46 redef fun provide_default_value
(key
) do
47 var res
= new Array[V
]
53 # Simple way to store an `HashMap[K1, HashMap[K2, V]]`
56 # var hm2 = new HashMap2[Int, String, Float]
59 # assert hm2[1, "one"] == 1.0
60 # assert hm2[2, "not-two"] == null
62 class HashMap2[K1, K2, V
]
63 private var level1
= new HashMap[K1, HashMap[K2, V
]]
65 # Return the value associated to the keys `k1` and `k2`.
66 # Return `null` if no such a value.
67 fun [](k1
: K1, k2
: K2): nullable V
69 var level1
= self.level1
70 if not level1
.has_key
(k1
) then return null
71 var level2
= level1
[k1
]
72 if not level2
.has_key
(k2
) then return null
76 # Set `v` the value associated to the keys `k1` and `k2`.
77 fun []=(k1
: K1, k2
: K2, v
: V
)
79 var level1
= self.level1
80 var level2
: HashMap[K2, V
]
81 if not level1
.has_key
(k1
) then
82 level2
= new HashMap[K2, V
]
90 # Remove the item at `k1` and `k2`
91 fun remove_at
(k1
: K1, k2
: K2)
93 var level1
= self.level1
95 if not level1
.has_key
(k1
) then return
97 var level2
= level1
[k1
]
98 level2
.keys
.remove
(k2
)
102 # Simple way to store an `HashMap[K1, HashMap[K2, HashMap[K3, V]]]`
105 # var hm3 = new HashMap3[Int, String, Int, Float]
106 # hm3[1, "one", 11] = 1.0
107 # hm3[2, "two", 22] = 2.0
108 # assert hm3[1, "one", 11] == 1.0
109 # assert hm3[2, "not-two", 22] == null
111 class HashMap3[K1, K2, K3, V
]
112 private var level1
= new HashMap[K1, HashMap2[K2, K3, V
]]
114 # Return the value associated to the keys `k1`, `k2`, and `k3`.
115 # Return `null` if no such a value.
116 fun [](k1
: K1, k2
: K2, k3
: K3): nullable V
118 var level1
= self.level1
119 if not level1
.has_key
(k1
) then return null
120 var level2
= level1
[k1
]
121 return level2
[k2
, k3
]
124 # Set `v` the value associated to the keys `k1`, `k2`, and `k3`.
125 fun []=(k1
: K1, k2
: K2, k3
: K3, v
: V
)
127 var level1
= self.level1
128 var level2
: HashMap2[K2, K3, V
]
129 if not level1
.has_key
(k1
) then
130 level2
= new HashMap2[K2, K3, V
]
138 # Remove the item at `k1`, `k2` and `k3`
139 fun remove_at
(k1
: K1, k2
: K2, k3
: K3)
141 var level1
= self.level1
143 if not level1
.has_key
(k1
) then return
145 var level2
= level1
[k1
]
146 level2
.remove_at
(k2
, k3
)
150 # A map with a default value.
153 # var dm = new DefaultMap[String, Int](10)
154 # assert dm["a"] == 10
157 # The default value is used when the key is not present.
158 # And getting a default value does not register the key.
161 # assert dm["a"] == 10
162 # assert dm.length == 0
163 # assert dm.has_key("a") == false
166 # It also means that removed key retrieve the default value.
170 # assert dm["a"] == 2
171 # dm.keys.remove("a")
172 # assert dm["a"] == 10
175 # Warning: the default value is used as is, so using mutable object might
176 # cause side-effects.
179 # var dma = new DefaultMap[String, Array[Int]](new Array[Int])
182 # assert dma["a"] == [65]
183 # assert dma.default == [65]
184 # assert dma["c"] == [65]
187 # assert dma["b"] == [65, 66]
188 # assert dma.default == [65]
190 class DefaultMap[K
, V
]
196 redef fun provide_default_value
(key
) do return default