<form method="POST">
    <h3>Editing: KeywordEmulator.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php declare(strict_types=1);

namespace PhpParser\Lexer\TokenEmulator;

use PhpParser\Token;

abstract class KeywordEmulator extends TokenEmulator {
    abstract public function getKeywordString(): string;
    abstract public function getKeywordToken(): int;

    public function isEmulationNeeded(string $code): bool {
        return strpos(strtolower($code), $this-&gt;getKeywordString()) !== false;
    }

    /** @param Token[] $tokens */
    protected function isKeywordContext(array $tokens, int $pos): bool {
        $previousNonSpaceToken = $this-&gt;getPreviousNonSpaceToken($tokens, $pos);
        return $previousNonSpaceToken === null || $previousNonSpaceToken-&gt;id !== \T_OBJECT_OPERATOR;
    }

    public function emulate(string $code, array $tokens): array {
        $keywordString = $this-&gt;getKeywordString();
        foreach ($tokens as $i =&gt; $token) {
            if ($token-&gt;id === T_STRING &amp;&amp; strtolower($token-&gt;text) === $keywordString
                    &amp;&amp; $this-&gt;isKeywordContext($tokens, $i)) {
                $token-&gt;id = $this-&gt;getKeywordToken();
            }
        }

        return $tokens;
    }

    /** @param Token[] $tokens */
    private function getPreviousNonSpaceToken(array $tokens, int $start): ?Token {
        for ($i = $start - 1; $i &gt;= 0; --$i) {
            if ($tokens[$i]-&gt;id === T_WHITESPACE) {
                continue;
            }

            return $tokens[$i];
        }

        return null;
    }

    public function reverseEmulate(string $code, array $tokens): array {
        $keywordToken = $this-&gt;getKeywordToken();
        foreach ($tokens as $token) {
            if ($token-&gt;id === $keywordToken) {
                $token-&gt;id = \T_STRING;
            }
        }

        return $tokens;
    }
}
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