1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2012 Jean Privat <jean@pryen.org>
5 # Licensed under the Apache License, Version 2.0 (the "License");
6 # you may not use this file except in compliance with the License.
7 # You may obtain a copy of the License at
9 # http://www.apache.org/licenses/LICENSE-2.0
11 # Unless required by applicable law or agreed to in writing, software
12 # distributed under the License is distributed on an "AS IS" BASIS,
13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 # See the License for the specific language governing permissions and
15 # limitations under the License.
17 # management and display of ordered trees
20 # Generic structure to manage and display an ordered tree
22 # Ordered tree are tree where the elements of a same parent are in a specific order
24 # The class can be used as it to work with generic tree.
25 # The class can also be specialized to provide more specific behavior.
26 class OrderedTree[E
: Object]
30 var roots
= new Array[E
]
31 var sub
= new HashMap[E
, Array[E
]]
33 # Add a new element `e` in the tree
34 # `p` is the parent of `e`.
35 # if `p` is null, then `e` is a root element.
37 # By defauld, the elements with a same parent
38 # are displayed in the order they are added.
40 # The `sort_with` method can be used reorder elements
41 fun add
(p
: nullable E
, e
: E
)
45 else if sub
.has_key
(p
) then
52 # print the full tree on `o`
53 # Write a ASCII-style tree and use the `display` method to label elements
54 redef fun write_to
(stream
: OStream)
58 stream
.write display
(r
)
60 sub_write_to
(stream
, r
, "")
64 private fun sub_write_to
(o
: OStream, e
: E
, prefix
: String)
66 if not sub
.has_key
(e
) then return
71 o
.write
"{prefix}|--{display(e2)}\n"
72 sub_write_to
(o
, e2
, prefix
+"| ")
74 o
.write
"{prefix}`--{display(e2)}\n"
75 sub_write_to
(o
, e2
, prefix
+" ")
80 # Sort roots and other elements using a comparator method
81 # This method basically sorts roots then each group of children
82 fun sort_with
(comparator
: Comparator[E
])
84 comparator
.sort
(roots
)
85 for a
in sub
.values
do
90 # How to display a specific element of the tree
91 # By defaut, uses `to_s`
93 # Subclasses should redefine this method to provide a specific output
94 fun display
(e
: E
): String do return e
.to_s