<?php

require_once __DIR__ . '/vendor/autoload.php';

use PHPStan\PhpDocParser\Ast\PhpDoc\ParamTagValueNode;
use PHPStan\PhpDocParser\Ast\PhpDoc\PhpDocNode;
use PHPStan\PhpDocParser\Ast\Type\IdentifierTypeNode;
use PHPStan\PhpDocParser\Lexer\Lexer;
use PHPStan\PhpDocParser\Parser\ConstExprParser;
use PHPStan\PhpDocParser\Parser\PhpDocParser;
use PHPStan\PhpDocParser\Parser\TokenIterator;
use PHPStan\PhpDocParser\Parser\TypeParser;

// basic setup

$lexer = new Lexer();
$constExprParser = new ConstExprParser();
$typeParser = new TypeParser($constExprParser);
$phpDocParser = new PhpDocParser($typeParser, $constExprParser);

// parsing and reading a PHPDoc string

$tokens = new TokenIterator($lexer->tokenize('/** @param Lorem $a */'));
$phpDocNode = $phpDocParser->parse($tokens); // PhpDocNode
$paramTags = $phpDocNode->getParamTagValues(); // ParamTagValueNode[]
echo $paramTags[0]->parameterName; // '$a'
echo $paramTags[0]->type; // IdentifierTypeNode - 'Lorem'

<?php

require_once __DIR__ . '/vendor/autoload.php';

use PHPStan\PhpDocParser\Ast\NodeTraverser;
use PHPStan\PhpDocParser\Ast\NodeVisitor\CloningVisitor;
use PHPStan\PhpDocParser\Ast\PhpDoc\PhpDocNode;
use PHPStan\PhpDocParser\Ast\Type\IdentifierTypeNode;
use PHPStan\PhpDocParser\Lexer\Lexer;
use PHPStan\PhpDocParser\Parser\ConstExprParser;
use PHPStan\PhpDocParser\Parser\PhpDocParser;
use PHPStan\PhpDocParser\Parser\TokenIterator;
use PHPStan\PhpDocParser\Parser\TypeParser;
use PHPStan\PhpDocParser\Printer\Printer;

// basic setup with enabled required lexer attributes

$usedAttributes = ['lines' => true, 'indexes' => true];

$lexer = new Lexer();
$constExprParser = new ConstExprParser(true, true, $usedAttributes);
$typeParser = new TypeParser($constExprParser, true, $usedAttributes);
$phpDocParser = new PhpDocParser($typeParser, $constExprParser, true, true, $usedAttributes);

$tokens = new TokenIterator($lexer->tokenize('/** @param Lorem $a */'));
$phpDocNode = $phpDocParser->parse($tokens); // PhpDocNode

$cloningTraverser = new NodeTraverser([new CloningVisitor()]);

/** @var PhpDocNode $newPhpDocNode */
[$newPhpDocNode] = $cloningTraverser->traverse([$phpDocNode]);

// change something in $newPhpDocNode
$newPhpDocNode->getParamTagValues()[0]->type = new IdentifierTypeNode('Ipsum');

// print changed PHPDoc
$printer = new Printer();
$newPhpDoc = $printer->printFormatPreserving($newPhpDocNode, $phpDocNode, $tokens);
echo $newPhpDoc; // '/** @param Ipsum $a */'