goutte/tree-bundle

Goutte's Rooted Tree Library

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Language: PHP

v1.7.5 2013-01-07 07:21 UTC

README

The Tree structure is currently designed with only one model, the Node.

Provides a service for serializing and unserializing nodes, to and from strings such as A(B,C(D)).

Drivers provided :

  • Parenthesis : A(B,C(D))
  • Simple (dumb!) timbre : T("*",T(6),T("sin",T(55.2)))
  • Ascii

    A
    +--B
    |  +--C
    |  +--D
    |     +--E
    +--Fork
    

See the Tests for more examples of what the Drivers support.

How to Use

This is not for storing nested sets in the database, if that is what you are looking for you should be looking at Doctrine Extensions. The original purpose of this bundle is to provide a toolset for reading/writing functional code, or configuring the hierarchy of a menu in plain text for example.

Feel free to extend it to suit your needs, though.

Install

Add this bundle to your project using composer

composer require goutte/tree-bundle

Service

Use the service from the container :

    // get the serializer service
    $serializer = $container->get('goutte_tree.serializer');

    // this will create the nodes and return the root node
    $rootNode = $serializer->toNode('root(childA,childB(grandchildC))');

    // this will return the string for the subtree below the passed node
    $string = $serializer->toString($rootNode); // returns 'root(childA,childB(grandchildC))'

    // ... or use another driver
    $string = $serializer->useDriver('ascii')->toString($rootNode);
    // will return:
    // root
    // +--childA
    // +--childB
    //    +--grandchildC

See Goutte\TreeBundle\Is\Node for a list of the methods provided by the abstract class Goutte\TreeBundle\Model\AbstractNode.

Using your own Node

Extending

    use Goutte\TreeBundle\Model\Node as AbstractNode;
    class MyNode extends AbstractNode {
        // ...
    }

Implementing

    use Goutte\TreeBundle\Is\Node as NodeInterface;
    class MyNode implements NodeInterface {
        // ...
    }

Then, configure the service to use your own Node class.

Writing a Driver

Implement Goutte\TreeBundle\Is\Driver as follows :

    use Goutte\TreeBundle\Is\Driver;
    use Goutte\TreeBundle\Factory\NodeFactoryInterface;

    class MyDriver implements Driver
    {
        protected $factory

        public function __construct(NodeFactoryInterface $factory)
        {
            $this->factory = $factory;
        }

        // ... implement Driver
    }

The __construct part is optional, but you'll probably want a NodeFactory to create Nodes. We provide a default Node Factory as service, see the <argument> in the service definition below.

Add your driver to your services.xml, and tag it goutte_tree.driver :

    <service id="goutte_tree.driver.mydriver" class="MyVendor\MyBundle\Driver\MyDriver" public="false">
        <argument type="service" id="goutte_tree.node.factory" />
        <tag name="goutte_tree.driver" />
    </service>

(warn) The service id will define the driver alias, so it needs to start with goutte_tree.driver.. It is not the documented way of doing such a thing (which would be having an alias attribute in the tag), but it is a bit DRYer. This may be subject to change later, I'm still making up my mind.

Configure the service to use your custom driver with ->useDriver() :

    // Get the service, tell it to use your driver
    $serializer = $container->get('goutte_tree.serializer')->useDriver('mydriver');

You may skip usage of ->useDriver() by telling the service to use your driver as default in the services.xml :

    <tag name="goutte_tree.driver" default="true" />

Testing

This bundle is ruthlessly tested, except for some service configuration exceptions (if you know how to test these, I'm all ears!)

Run composer with the --dev option so that the autoloader is created and the needed sf2 DIC classes are autoloaded. Oddly enough, when I tried to install with --test and require-test in the composer.json, I was sent packing. (pun intended)

composer install --dev

Then, simply run

phpunit

Pitfalls

Parenthesis Driver

Nodes with empty label can convert to string, but not back to node.

Eg: A(B,C) tree, if nodes' labels are emptied, will convert back to (,)

Envisioned solutions :

  • Throw on toString conversion if label is empty -> loss of feature
  • Tweak the toNode regex to allow empty labels -> disturbing as A() will create two nodes for example

Timbre Driver

The nodes labels are not escaped by the driver, so no (, ) or ,. As these characters are not used by Timbre's nodes, this should not be a problem.

Numerical labels must be encapsulated in T(), like so : T(66.2).

Ascii Driver

Linebreaks will be (un)escaped so that labels stay on one line in the string representation.

Because the reader expects exactly 2 - as indentation, the Node label will hold the extra - if you add more.

Eg:

A
+---B

=> The child node's label will be -B, not B.

ChangeLog

v1.0

  • TreeIntegrityException
  • DriverException
  • Node base methods
  • Path finding
  • Tree integrity tests
  • DIC for Drivers
  • Documentation

v1.5

  • Parenthesis driver
  • Timbre driver
  • AsciiDriver for multiline ascii rooted trees
  • Node replacement with ->replaceBy()

v1.6

  • Node cloning

v1.7.1

  • ->getDescendants() (breadth-first TWA by default)
  • ->getRandomDescendant($includeSelf=false)

v1.7.4

  • Decoupling the Random util for easier/deeper deteministic testing
  • ->removeChildren()

v1.7.5

  • Usage of Factories in Drivers

RoadMap

These have no schedule, don't wait for them.

v1.8

  • ->getAncestors()
  • ->getRandomAncestor($includeSelf=false)

v2.0

  • Empty labels in parenthesis driver
  • Graph theory, see the BLACKBOARD
    • -> probably in another bundle
  • Custom tree walking for tree flattening
    • breadth-first
    • depth-first