jlvn / tree-transform
A library to perform transformations on tree-like structures.
Requires
- php: >=7.4
Requires (Dev)
- phpunit/phpunit: ^9.5
- vimeo/psalm: ^4.22
This package is auto-updated.
Last update: 2024-05-22 15:19:58 UTC
README
A library to perform transformations on tree-like structures.
Usage
This library exposes a main class called: TreeTransformer
.
With this class a user can transform a tree-like structure with different data-types
on a data-type by data-type basis.
This is done using so-called TreeTransformable
s.
TreeTransformables
A TreeTransformable defines the transforming behaviour of a certain data-type.
All TreeTransformables must implement the TreeTransformableInterface
.
Using the GenericTreeTransformable class
This library exposes the GenericTreeTransformable
class. With this class TreeTransformables can be
created on the fly without having to define a class for each data type.
// A transformable that transforms a string into an array of strings $stringTreeTransformable = new GenericTreeTransformable( gettype(''), // the tag of the transformable. 'string' in this case. fn() => [], // the branches of the current transformable. None in this case. fn(string $trunk) => split('', $trunk), // the transform function )
implementing your own transformables
Another option is to simply implement the TreeTransformableInterface
for your own specific data type.
class Custom { public string $name; public array $children; } class CustomTreeTransformable implements TreeTransformableInterface { public function getTag(): string { return Custom::class } public function getBranches($trunk): array { return $trunk->children; } public function transform($trunk, ReadOnlyMapInterface $branches) { return [ 'name' => $trunk->name, 'customChildren' => $branches->getOrDefault(Custom::class, []) ] } }
Using the TreeTransformer
Now that we have defined our TreeTransformable
s we can use them in the TreeTransformer.
The TreeTransformer uses a simple depth first algorithm to traverse the tree.
Tou can interact with the TreeTransformer in a multitude of ways.
$transformer = new TreeTransformer; // Throws a NotFoundException when the transformable with a certain tag is not found. $transformer->tryTransform($data); // uses a default transformable (PlaceboTreeTransformer by default) when the transformable // with a certain tag is not found. $transformer->transformOrDefault($data);
Usage with method supplied transformables
$transformer = new TreeTransformer; $transformableMap = new TreeTransformableTagReadOnlyMap([ $stringTreeTransformable, new CustomTreeTransformable ]); try { $transformer->tryTransform($data, $transformableMap); } catch(NotfoundException $e) { // thrown if transformable is not found } $transformer->transformOrDefault($data, $transformableMap); //it is also possible to supply a new default transformable $transformer->transformOrDefault($data, $transformableMap, $stringTreeTransformable);
Usage with constructor or default supplied transformables
$transformableMap = new TreeTransformableTagReadOnlyMap([ $stringTreeTransformable, new CustomTreeTransformable ]); $transformer = new TreeTransformer($stringTreeTransformable, $transformableMap); try { $transformer->tryTransform($data); } catch(NotfoundException $e) { // thrown if transformable is not found } $transformer->transformOrDefault($data);