Just ran this from the readme:
composer create-project pattern-lab/edition-development-twig pattern-library && cd $_
And got this:
> PatternLab\Installer::postUpdateCmd
PHP Parse error: syntax error, unexpected ')' in /Users/bdub/Projects/envirovantage-web-api-symfony/pattern-library/vendor/pattern-lab/core/src/PatternLab/InstallerUtil.php on line 353
Sure enough, in that file, there's an extra paren:
line 353:
$pathName = $file->getPathname());