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Visitors

GraPHP UML

ParentContextVisitor

The AST does not store parent nodes by default. However, the ParentContextVisitor is used to achieve this in the following context: when elements are either class, interface, trait, function, closure, method, arrow function and property.

The parent context visitor accepts an option array as the first argument, with the following default values:

  • the nodeAttributeParentKeyStore option contains the name of a new node attribute (default to bartlett.parent) that will store the parent node of only elements referenced above.

The AST does not include a namespace node (PhpParser\Node\Stmt\Namespace_) when source code is only in global namespace. The second goal of ParentContextVisitor is to add this node at top of node list to traverse (during the beforeTraverse method).

That will allow the CompatibilityAnalyser to show PHP versions required of full code in global namespace context.

For example with such script: 

<?php declare(strict_types=1);

function returnArray() {
    return ['one', 'two', 'three'];
}
$arrayValue1 = returnArray()[0];

PHP versions detected are :

  • 7.0.0 for full script, due to declare directive usage.
  • 5.4.0 for short array usage in returnArray function.
  • 5.4.0 for usage of array dereferencing syntax when calling returnArray function.

NameResolverVisitor

The NameResolverVisitor is applied to resolve names of each major elements where the PHP versions should be detected. It extends the basic Name Resolver by default that did not add namespacedName property on all elements.

The name resolver accepts an option array as the second argument, with the following default values:

  • the nodeAttributeParentKeyStore option contains the name of a new node attribute (default to bartlett.parent) that reference the parent node of the following elements : class, interface, trait, function, closure, method, arrow function and property.

After running this visitor, the parent node can be obtained through $node->getAttribute('bartlett.parent'). This will be useful with the CompatibilityAnalyser that should give PHP versions of each element including in their parent context.

VersionResolverVisitor

The VersionResolverVisitor is in charge to initialize PHP versions on each element (namespace, class, interface, trait, function, closure, method or arrow function nodes) of source code context.

The version resolver accepts an option array as the second argument, with the following default values:

  • the nodeAttributeParentKeyStore option contains the name of a new node attribute (default to bartlett.parent). Its value must be the same as the option used in the NameResolverVisitor.

  • the nodeAttributeKeyStore option contains the name of a new node attribute (default to bartlett.data_collector) that store the PHP versions of major elements.

After running this visitor, the PHP versions can be obtained through $node->getAttribute('bartlett.data_collector'). This will be useful with the CompatibilityAnalyser.

When user classes, interfaces or traits referenced extensions elements (with type hinting, parameters and return), it will call a local SQLite database to get information. Current database project supports all data for almost a hundred extensions on each PHP versions from 5.2.17 to latest 7.4

The version resolver accepts an instance of Bartlett\CompatInfo\Collection\ReferenceCollectionInterface as the first argument.

This collection referenced all information in the SQLite database.

FilterVisitor

The FilterVisitor is applied to retrieve all AST nodes that have attributes identified by nodeAttributeKeyStore option.

  • Data in final format are retrieved by the FilterVisitor::getCollection() method.
  • Data are normalized with the normalizer of the Symfony Serializer component, and transformed from internal format to final format by the NodeNormalizer of DataCollector.

This visitor is used by the VersionDataCollector.