[gergoerdi]

Here's an example where I used, if not the Yoneda lemma, its categorical dual the co-Yoneda lemma (named `MarketRequest` in this post because I didn't know about it at that point so had to reinvent it to my particular use case) to solve a very real software engineering problem: http://unsafePerform.IO/blog/2012-12-01-static_analysis_with...