hehe.org/vendor/symfony/yaml/Dumper.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Yaml;

use Symfony\Component\Yaml\Tag\TaggedValue;

/**
 * Dumper dumps PHP variables to YAML strings.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 *
 * @final
 */
class Dumper
{
    /**
     * The amount of spaces to use for indentation of nested nodes.
     *
     * @var int
     */
    protected $indentation;

    public function __construct(int $indentation = 4)
    {
        if ($indentation < 1) {
            throw new \InvalidArgumentException('The indentation must be greater than zero.');
        }

        $this->indentation = $indentation;
    }

    /**
     * Dumps a PHP value to YAML.
     *
     * @param mixed $input  The PHP value
     * @param int   $inline The level where you switch to inline YAML
     * @param int   $indent The level of indentation (used internally)
     * @param int   $flags  A bit field of Yaml::DUMP_* constants to customize the dumped YAML string
     *
     * @return string The YAML representation of the PHP value
     */
    public function dump($input, int $inline = 0, int $indent = 0, int $flags = 0): string
    {
        $output = '';
        $prefix = $indent ? str_repeat(' ', $indent) : '';
        $dumpObjectAsInlineMap = true;

        if (Yaml::DUMP_OBJECT_AS_MAP & $flags && ($input instanceof \ArrayObject || $input instanceof \stdClass)) {
            $dumpObjectAsInlineMap = empty((array) $input);
        }

        if ($inline <= 0 || (!\is_array($input) && !$input instanceof TaggedValue && $dumpObjectAsInlineMap) || empty($input)) {
            $output .= $prefix.Inline::dump($input, $flags);
        } else {
            $dumpAsMap = Inline::isHash($input);

            foreach ($input as $key => $value) {
                if ($inline >= 1 && Yaml::DUMP_MULTI_LINE_LITERAL_BLOCK & $flags && \is_string($value) && false !== strpos($value, "\n") && false === strpos($value, "\r\n")) {
                    // If the first line starts with a space character, the spec requires a blockIndicationIndicator
                    // http://www.yaml.org/spec/1.2/spec.html#id2793979
                    $blockIndentationIndicator = (' ' === substr($value, 0, 1)) ? (string) $this->indentation : '';
                    $output .= sprintf("%s%s%s |%s\n", $prefix, $dumpAsMap ? Inline::dump($key, $flags).':' : '-', '', $blockIndentationIndicator);

                    foreach (preg_split('/\n|\r\n/', $value) as $row) {
                        $output .= sprintf("%s%s%s\n", $prefix, str_repeat(' ', $this->indentation), $row);
                    }

                    continue;
                }

                if ($value instanceof TaggedValue) {
                    $output .= sprintf('%s%s !%s', $prefix, $dumpAsMap ? Inline::dump($key, $flags).':' : '-', $value->getTag());

                    if ($inline - 1 <= 0) {
                        $output .= ' '.$this->dump($value->getValue(), $inline - 1, 0, $flags)."\n";
                    } else {
                        $output .= "\n";
                        $output .= $this->dump($value->getValue(), $inline - 1, $dumpAsMap ? $indent + $this->indentation : $indent + 2, $flags);
                    }

                    continue;
                }

                $dumpObjectAsInlineMap = true;

                if (Yaml::DUMP_OBJECT_AS_MAP & $flags && ($value instanceof \ArrayObject || $value instanceof \stdClass)) {
                    $dumpObjectAsInlineMap = empty((array) $value);
                }

                $willBeInlined = $inline - 1 <= 0 || !\is_array($value) && $dumpObjectAsInlineMap || empty($value);

                $output .= sprintf('%s%s%s%s',
                    $prefix,
                    $dumpAsMap ? Inline::dump($key, $flags).':' : '-',
                    $willBeInlined ? ' ' : "\n",
                    $this->dump($value, $inline - 1, $willBeInlined ? 0 : $indent + $this->indentation, $flags)
                ).($willBeInlined ? "\n" : '');
            }
        }

        return $output;
    }
}