Haskell's deriving construct is both wonderful and magical at the same time: it is wonderful, because with just a single line of code, you can obtain functionality such as(de)serialization, comparison and traversal functions for your newly defined datatype; it is magical because all of this happens behind the scenes, by code deeply built into the compiler.

But does it have to be magic? Since recently, the Glasgow Haskell Compiler (GHC) supports a feature that lets you define your own derivable functionality! And it is not difficult to use, either. All you have to do is to understand a little bit about how Haskell datatypes can be uniformly represented using a limited set of simple datatypes. Then you define a class plus instances for this limited set of types, and get all the rest for free.

So-called datatype-generic functions let you properly express your code in terms of specific, user-defined datatypes without paying a price: for your new datatypes, you can still use lots of pre-defined functionality, simply by deriving it.

In the talk, I will explain all about how datatype-generic programming in GHC works, and I will present several examples of its use, including examples of how it already is successfully being used in some prominent Haskell libraries.

	Developing Python with PyDev : 21st May 2013
	Datatype-Generic Programming in Haskell Andres Löh : 9th Apr 2013
	Lambda|Wars Andrey Levushkin : 20th Mar 2013
	Reducing cognitive bias in design with Paul Dale : 15th Mar 2013
	Elnode: the evented IO web server Nic Ferrier : 15th Mar 2013
	Adventures with types Simon Peyton Jones : 15th Mar 2013
	Across Time and Address Space: Lift 3.0 David Pollak : 15th Mar 2013
	LexiFi: describing financial contracts a Alain Frisch : 15th Mar 2013
	Comparing Scala and Clojure Robert Rees : 15th Mar 2013
	F# in the open source world Don Syme : 15th Mar 2013
	This Year in Emacs Nic Ferrier : 19th Feb 2013
	Lambda|Wars Andrey Levushkin : 6th Feb 2013
	Clojure at Nokia Entertainment... Andrew Jones : 22nd Jan 2013
	Lambda|Wars Andrey Levushkin : 11th Dec 2012
	Practical Functional-first Programming w Don Syme : 1st Nov 2012