At https://gist.github.com/ckirkendall/2934374 you find solutions in many languages to a simple programming problem: the evaluation of an expression in an environment. I want to point your attention to the currently last three entries: - one using the UUAGC compiler to solve the problem in an aspect oriented way (entered by Jeroen Bransen (jbransen)) - one using some Haskell features, libraries and extensions (entered by me (doaitse)) - one using our attribute grammar combinators from the AspectAG package, which expresses the various aspects in an attribute grammar style (entered by Marcos Viera (marcosomarviera)) In case you did not manage to avoid getting wound up in a discussion about programming languages you can find ammunition here. Doaitse