David Siegel - The Plenitude of Arboreal Beauty

I’m really fortunate to be taking some amazing courses from some awesome professors in my last semester as an undergrad at Penn; I’m taking a course on technology and policy from Matt Blaze, and another course on functional programming from Benjamin Pierce. After only a couple lectures from Matt Blaze on technology and privacy, I’ve become so terrified of identity theft that I canceled my PayPal account, removing my bank and credit card information from the web; I went through my Gmail, deleting all emails containing sensitive information; and I even stopped by the local RadioShack looking for a paper shredder. What a rush!

On a lighter note, my functional programming course has been a breath of fresh air after spending four months coding GNOME Do in C#; writing C# feels like writing a novel, while writing Haskell feels like writing a haiku. As part of our second assignment, we wrote functions to find the fringe, size, and height of a tree using higher-order functions:

This could be written more clearly, but just marvel at how concise the tree functions become when they are expressed in terms of a more abstract tree function, “treeOp”. treeOp takes one polymorphic function to apply to leaves and another polymorphic function to apply to branch values returned from recursive calls to treeOp. myFringe is expressed as a tree operation that applies :[] (the singleton list constructor) to leaf values and ++ (list concatenation function) to branches. The result of calling myFringe is an in-order list of leaf values. Amazing!