<story><title>Categories for Programmers: The Yoneda Lemma</title><url>http://bartoszmilewski.com/2015/09/01/the-yoneda-lemma/</url></story><parent_chain></parent_chain><comment><author>jonnybgood</author><text>This reminded of an OCamlers critique of Haskell [1], which I think raises a very good point:&lt;p&gt;&lt;i&gt;Yoneda-crazy: I know Haskell, I know some category theory, but I am highly sceptical that teaching the Yoneda Lemma to C++ programmers is actually useful in any way. I am the first to applaud the idea of scientific curiosity, of learning fun stuff of unclear usefulness just for the fun of it, but I think that a few excellent writers and tinkerers have given the Haskell community as a whole (and the foreigners that receive some of its TV shows by satellite) the wrong impression that the theoretical underpinning of typed functional programming is category theory. I would say that (1) it&amp;#x27;s a gross over-simplification of what the theory of typed functional programming is about, emphasizing a small part of it that has enabled some people to do very interesting things and (2) it is highly likely to be absolutely useless to an overwhelming large majority of the readers of such popularization material. Category Theory is fashionable these days, and I find the fashion aspect irritating -- it may be that I&amp;#x27;m just bitter? I&amp;#x27;m worried that we may have a backslash at some point when, you know, people realize that unless your initials are E.K. you are wasting your time thinking about the co-density transformation. On the other hand, this category circus has been going on for years, and I believe nobody has been hurt so far, so maybe it&amp;#x27;s just fine. &lt;/i&gt;&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.reddit.com&amp;#x2F;r&amp;#x2F;ocaml&amp;#x2F;comments&amp;#x2F;3ifwe9&amp;#x2F;what_are_ocamlers_critiques_of_haskell&amp;#x2F;cugbbbw&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.reddit.com&amp;#x2F;r&amp;#x2F;ocaml&amp;#x2F;comments&amp;#x2F;3ifwe9&amp;#x2F;what_are_ocam...&lt;/a&gt;</text></comment>
<story><title>Categories for Programmers: The Yoneda Lemma</title><url>http://bartoszmilewski.com/2015/09/01/the-yoneda-lemma/</url></story><parent_chain></parent_chain><comment><author>mordocai</author><text>Started reading this, was confused, thought &amp;quot;WTH this is for programmers(not computer scientists)?&amp;quot;. Then realized it is part 14. Oh well, guess I need to start at part 1...</text></comment>