You don&#x27;t <i>need</i> any of them. This is a good guide to them <a href="http:&#x2F;&#x2F;dev.stephendiehl.com&#x2F;hask&#x2F;#language-extensions" rel="nofollow">http:&#x2F;&#x2F;dev.stephendiehl.com&#x2F;hask&#x2F;#language-extensions</a>