Archive for the 'fp@cs' Category

October 9 Meeting of the Functional Programming Reading Group

October 9, 2008

We reviewed “Why Functional Programming Matters”, by John Hughes.

Along the way, we discussed some foundational FP concepts, such as currying, closures and functors.

Eventually, we’d like to move to a model where each meeting we cover a set of papers. Each of us reads a different one in depth and skims the others. At the meeting each of us will teach the deeply studied concepts to the others.

We agreed that we needed more foundational material before we begin to specialize. We also agreed that we’d like to move in a more theoretical direction for now—for example, we’ll look at some type theory, lambda calculus, and category theory.

I found an online book called “Type Theory and Functional Programming.” [PDF] We’ll read chapters 2 & 3 for the next meeting in two weeks: October 23.

Notes on “Why Functional Programming Matters”

October 8, 2008

Why Functional Programming Matters: John Hughes

Two functional language features, higher-order functions and lazy evaluation, allow for improved modularity in computer programs. For this reason, functional languages are important.

For example, reduce over lists and trees can be used to create other powerful functions such as sum, product and map. An abstraction for iterative improvement algorithms allows for simple square root calculations, derivatives and integrals. A combination of higher-order functions and lazy evaluation allows for a simple minimax implementation with alpha-beta pruning.

The first few examples given in this paper are drawn from the Structure and Interpretation of Computer Programs. This overlap makes me wonder: Perhaps functional languages are excellent for these specific tasks, or perhaps it is difficult to discover new generally useful functional abstractions.

September 25 Meeting of the Functional Programming Reading Group

September 26, 2008

We went over McCarthy’s Recursive Functions of Symbolic Expressions, discussed the paper and cleared up some confusion.

We’re going to try to meet at 5pm on Thursday October 9th, to allow for the people who have Algorithmic Software Verification at noon.

The paper to be discussed is “Why Functional Programming Matters,” by John Hughes. PDF Link.

Inaugural meeting of Functional Programming reading group

September 17, 2008

Sept. 16 2008, Bahen 5250.

Six in attendance of nine on the list. Not a bad start.

Abe led a brief discussion of basics of FP for beginners, and suggests we check out Lambda the Ultimate.

We’ll meet again and BA 5250 on Thursday September 25th, 12pm-1pm. The paper to read is John McCarthy’s Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I.