Jencel Panic<p>A <a href="https://mathstodon.xyz/tags/monad" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>monad</span></a> is when you know how to convert $M (M a)$ to $M a$, but not $M a$ to $a$.</p><p><a href="https://mathstodon.xyz/tags/haskell" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>haskell</span></a> <a href="https://mathstodon.xyz/tags/categorytheory" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>categorytheory</span></a> <a href="https://mathstodon.xyz/tags/functionalprogramming" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>functionalprogramming</span></a></p>