Tool for changing "var" keywords to "public" in PHP

portVarKeywords.php

<?php

/*
 * Note: This script will directly modify the .php files in the given directory.
 * It is assumed that the code is under version control, so you can easily review
 * the changes using `git diff` or similar.
 */

function usageError() {
    die("Usage: php portVarKeywords.php dir/\n");
}

if ($argc !== 2) {
    usageError();
}

$dir = $argv[1];
if (!is_dir($dir)) {
    echo "\"$dir\" is not a directory.\n";
    usageError();
}

$it = new RecursiveIteratorIterator(
    new RecursiveDirectoryIterator($dir),
    RecursiveIteratorIterator::LEAVES_ONLY
);

foreach ($it as $file) {
    if (!preg_match('/\.php$/', $file)) {
        continue;
    }

    $code = file_get_contents($file);

    $tokens = token_get_all($code);
    $tokens = portVarKeywords($tokens);

    $code = tokensToCode($tokens);

    file_put_contents($file, $code);
}

function portVarKeywords(array $tokens) {
    foreach ($tokens as $i => &$token) {
        if ($token[0] === T_VAR) {
            $token[1] = 'public';
        }
    }

    return $tokens;
}

function tokensToCode(array $tokens) {
    $code = '';
    foreach ($tokens as $token) {
        if (is_array($token)) {
            $code .= $token[1];
        } else {
            $code .= $token;
        }
    }
    return $code;
}