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Tree::Binary - Roles for building and traversing binary trees

use Tree::Binary; class IntTree does Tree::Binary::Role::BinaryTree[Int] {}; my IntTree(Str) $tree = "1(2)(3)"; say $tree;

```
1
┌┴┐
2 3
```

Tree::Binary is intended to be a framework that can be used as the basis for building binary trees. The core `Role`

provided is `Tree::Binary::Role::BinaryTree`

which encapsulates binary tree storage, traversing, parsing and rendering.

`Tree::Binary::Role::BinaryTree`

does not include code for inserting or deleting nodes as this is dependent on the concreate class using it.

role Tree::Binary::Role::BinaryTree[ ::ValueType=Any, Tree::Binary::Role::Renderer :$gist-renderer=Tree::Binary::PrettyTree, Tree::Binary::Role::Renderer :$Str-renderer=BasicStrRenderer, Tree::Binary::TraverseType :$traverse-type=Tree::Binary::TraverseType::InOrder, Tree::Binary::TraverseDirection :$traverse-direction=Tree::Binary::TraverseDirection::LeftToRight, ]

The Tree::Binary::Role::BinaryTree `Role`

accepts one postional and four named parameters :

**ValueType**

The type of object it should allow (defaulting to Any)

**:$gist-renderer**

An output renderer used for creating the `Tree::Binary::Role::BinaryTree`

's gist representation. The default for this is `Tree::Binary::PrettyTree`

but any class that does `Tree::Binary::Role::Renderer`

will work.

**:$Str-renderer**

An output renderer used for creating the `Tree::Binary::Role::BinaryTree`

's Str representation. The default for this is `BasicStrRenderer`

but any class that does `Tree::Binary::Role::Renderer`

will work.

**:$traverse-type**

How the tree should be iterated one of `Tree::Binary::Enums::TraverseType`

defaults to `Tree::Binary::TraverseType::InOrder`

**:$traverse-direction**

The direction the tree should be iterated one of `Tree::Binary::Enums::TraverseDirection`

defaults to `Tree::Binary::TraverseDirection::LeftToRight`

The default constructor takes two named arguments :

**ValueType :$value**

The value of the current node

**Array[Tree::Binary::Role::BinaryTree] :@nodes[2]**

An array of 0-2 Tree::Binary::Role::BinaryTree nodes that are the children of the current node.

The role also allows for basic string coercion where a tree can be represented with the following structure.

```
value(node1)(node2)
```

Where `value`

is a `Str`

that can be coerced into a `ValueType`

and `node1`

and `node2`

another `Tree::Binary`

representation. The `Str`

method should produce a value that can be coered into a Tree::Binary of the appropriate `ValueType`

.

Alternate construction options using `Str`

coercion are :

# Coercion from a Str to a Tree::Binary my Tree::Binary(Str) $tree1 = "1(a)(£)"; # Using the from-Str constructor my $tree2 = Tree::Binary.from-Str("1(a)(£)");

The child nodes

method nodes() returns Array[Tree::Binary::Role::BinaryTree]

The child nodes of this node, undefined nodes will not be returned.

method elems() returns UInt

Returns the number of defined nodes for the current node. Note that the elems method does NOT return the count of all nodes in the tree just the current nodes children.

method elems( Bool :$all! ) returns UInt

With the :all flag returns the total number of nodes in the tree including the current one but not any undefined ones.

method elems( Bool :$leaf! ) returns UInt

With the :leaf flag returns the total number of leaf nodes

method Str() returns Str

Returns a Str representation of the tree using the :$Str-renderer parameter

method gist() returns Str

Returns the gist for this tree using the defined $gist-renderer parameter

method raku() returns Str

Returns a raku representation of the tree

method reverse() returns Tree::Binary::Role::BinaryTree

Returns a new Tree::Binary where the node pairs have been swapped at each level

method from-Str( Str $in ) returns Tree::Binary::Role::BinaryTree

Object creation method using the Str coercion rules.

Scimon Proctor [email protected]

Copyright 2021 Scimon Proctor

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.