quick and bad script to migrate PHP heredoc out into a separate file

extract-heredoc.php

<?php

/*
usage:
  php extract-heredoc.php my-code-file.php

creates my-code-file.heredoc.php

assumes input file is a single <?php code block

manual correction of super-global usage is needed
  e.g. $_POST, $_REQUEST, etc

highly-recommended that changes be human-vetted
*/

if ($argc < 2) {
    echo 'not enough arguments';
    exit(1);
}

$inputPath = realpath($argv[1]);

if (preg_match('|\.php$|', $inputPath) !== 1) {
    echo 'filename must end with ".php"';
    exit(1);
}

$heredocFilename = basename($inputPath, '.php') . '.heredoc.php';
$heredocPath = dirname($inputPath) . '/' . $heredocFilename;

$input = file_get_contents($inputPath);

$output = preg_replace('|<\?php\n|', "<?php\n\ninclude '$heredocFilename';\n", $input);
$heredocs = '<?php' . PHP_EOL . PHP_EOL;

function generateName ($content) {
    return 'heredoc_' . substr(hash('sha256', $content), 0, 7);
}

$output = preg_replace_callback(
    '|<<<(\w+).*(\1);|msU',
    function ($matches) {
        global $heredocs;
        $paramsFound = array();
        preg_match_all('|[^\\\](\$\w+)|', $matches[0], $paramsFound);
        $params = array_unique($paramsFound[1]);

        $name = generateName($matches[0]);

        $heredocs .= "function $name (" . implode(', ', $params) . ') {' . PHP_EOL;
        $heredocs .= 'return ' . $matches[0] . PHP_EOL;
        $heredocs .= '}' . PHP_EOL . PHP_EOL;

        return $name . '(' . implode(', ', $params) . ');';
    },
    $output
);

file_put_contents($inputPath, $output);
file_put_contents($heredocPath, $heredocs);