function tokenize($code) {
    $regexes = [
        // ...
    ];

    $statements = split(' ', $code);
    $tokens = [];
    foreach($regexes as $regex) {
        foreach($statements as $statement) {
            $tokens[] = /* ... */;
        });
    });

    return $tokens;
}

function lexer($tokens) {
    $ast = [];
    foreach($tokens as $token) {
        $ast[] = /* ... */;
    });

    return $ast;
}

function parseBetterJSAlternative($code) {
    $tokens = tokenize($code);
    $ast = lexer($tokens);
    foreach($ast as $node) {
        // parse...
    });
}