$minifier = gulch\Minify\Minifier::createDefault();
// default optimizations are: whitespaces remove, html comments remove, minification of css and js code
// above code is equivalent to:
// $minifier = new gulch\Minify\Minifier(
//     new gulch\Minify\Processor\WhitespacesRemover,
//     new gulch\Minify\Processor\HtmlCommentsRemover,
//     new gulch\Minify\Processor\InlineCssMinifier,
//     new gulch\Minify\Processor\InlineJavascriptMinifier,
// );
$minified_code = $minifier->process($code);

$minifier = new gulch\Minify\Minifier(
    new gulch\Minify\Processor\WhitespacesRemover,
    new gulch\Minify\Processor\HtmlCommentsRemover,
    new gulch\Minify\Processor\InlineCssMinifier,
    new gulch\Minify\Processor\InlineJavascriptMinifier,
    new gulch\Minify\Processor\AttributesSimplifier,
    new gulch\Minify\Processor\AttributeQuotesRemover,
);
$minified_code = $minifier->process($code);