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https://github.com/titsuki/raku-algorithm-zhangshasha
Tree edit distance between trees
https://github.com/titsuki/raku-algorithm-zhangshasha
edit perl6 raku tree zhangshasha
Last synced: 11 days ago
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Tree edit distance between trees
- Host: GitHub
- URL: https://github.com/titsuki/raku-algorithm-zhangshasha
- Owner: titsuki
- License: artistic-2.0
- Created: 2020-05-03T13:34:53.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2020-05-04T23:55:39.000Z (over 4 years ago)
- Last Synced: 2024-11-05T18:56:45.613Z (about 2 months ago)
- Topics: edit, perl6, raku, tree, zhangshasha
- Language: Raku
- Homepage:
- Size: 15.6 KB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: Changes
- License: LICENSE
Awesome Lists containing this project
README
[](https://travis-ci.org/titsuki/raku-Algorithm-ZhangShasha)
NAME
====
Algorithm::ZhangShasha - Tree edit distance between trees
SYNOPSIS
========
```perl6
use Algorithm::ZhangShasha;
my class SimpleHelper does Algorithm::ZhangShasha::Helpable[Algorithm::ZhangShasha::Node] {
method delete-cost(Algorithm::ZhangShasha::Node $this --> Int) {
1;
}
method insert-cost(Algorithm::ZhangShasha::Node $another --> Int) {
1;
}
method replace-cost(Algorithm::ZhangShasha::Node $this, Algorithm::ZhangShasha::Node $another --> Int) {
$another.content eq $this.content ?? 0 !! 1;
}
method children(Algorithm::ZhangShasha::Node $node) {
$node.children
}
}
my constant $ZN = 'Algorithm::ZhangShasha::Node';
my $root1 = ::($ZN).new(:content("f"))\
.add-child(::($ZN).new(:content("d"))\
.add-child(::($ZN).new(:content("a")))\
.add-child(::($ZN).new(:content("c"))\
.add-child(::($ZN).new(:content("b")))\
)\
)\
.add-child(::($ZN).new(:content("e")));
my $root2 = ::($ZN).new(:content("f"))\
.add-child(::($ZN).new(:content("c"))\
.add-child(::($ZN).new(:content("d"))\
.add-child(::($ZN).new(:content("a")))\
.add-child(::($ZN).new(:content("b")))\
)\
)\
.add-child(::($ZN).new(:content("e")));
my Algorithm::ZhangShasha::Tree[Algorithm::ZhangShasha::Node] $tree1 .= new(:root($root1), :helper(SimpleHelper.new));
my Algorithm::ZhangShasha::Tree[Algorithm::ZhangShasha::Node] $tree2 .= new(:root($root2), :helper(SimpleHelper.new));
say $tree1.tree-distance($tree2).key; # 2
say $tree1.tree-distance($tree2).value; # ({op => KEEP, pair => 1 => 1} {op => KEEP, pair => 2 => 2} {op => DELETE, pair => 3 => 2} {op => KEEP, pair => 4 => 3} {op => INSERT, pair => 4 => 4} {op => KEEP, pair => 5 => 5} {op => KEEP, pair => 6 => 6})
```
DESCRIPTION
===========
Algorithm::ZhangShasha is an implementation for efficiently computing tree edit distance between trees.
METHODS of Algorithm::ZhangShasha::Tree
---------------------------------------
### BUILD
Defined as:
```perl6
submethod BUILD(NodeT :$!root!, Algorithm::ZhangShasha::Helpable :$!helper!)
```
Creates an `Algorithm::ZhangShasha::Tree` instance.
* `$!root` is the root node of the tree
* `$!helper` is the helper class that implements four methods: `delete-cost`, `insert-cost`, `replace-cost`, `children`. If you want to combine 3rd-party node representation (e.g., `DOM::Tiny`), you should define a custom helper. (See `t/01-basic.t`. It implements an exmple for `DOM::Tiny`.)
### size
Defined as:
```perl6
method size(--> Int)
```
Returns the size of the tree.
### tree-distance
Defined as:
```perl6
method tree-distance(Algorithm::ZhangShasha::Tree $another --> Pair)
```
Returns a `Pair` instance that has the optimal edit distance and the corresponding operations (e.g., DELETE(3,2)) between the two trees. Where `.key` has the distance and `.value` has the operations.
AUTHOR
======
Itsuki Toyota
COPYRIGHT AND LICENSE
=====================
Copyright 2020 Itsuki Toyota
This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.
This algorithm is from
* [0] Zhang, Kaizhong, and Dennis Shasha. "Simple fast algorithms for the editing distance between trees and related problems." SIAM journal on computing 18.6 (1989): 1245-1262.