title: Replacing "->"s with "→"s, "=>"s with "⇒"s and so on in Haskell
body: <p>There are a lot of interesting <a href="/questions/tagged/haskell" class="post-tag" title="show questions tagged &#39;haskell&#39;" rel="tag">haskell</a> snippets to be found online. <a href="https://gergo.erdi.hu/blog/2012-12-01-static_analysis_with_applicatives/" rel="noreferrer">This post</a> could be found under <a href="https://stackoverflow.com/questions/12001350/useful-operations-on-free-arrows">this (awesome) Stack Overflow question</a>. <a href="https://stackoverflow.com/users/477476/cactus">The author</a> writes the following:</p>
  <pre class="lang-hs prettyprint-override"><code>discount ∷ Floating α ⇒ α → α → α → α
  discount τ df x = x * (1 + df) ** (-τ)
  </code></pre>
  <p>Are those fancy arrows and dots just a way to make the online page look nicer, or is there an actual Haskell extension (or whatever, I don't quite know the terminology) which would compile something like that? I should note that the usual <code>-&gt;</code> is used in the code just as well.</p>
  <p>I have a strong feeling it's not the first time I see things like that.</p>