Patterns in Functional Programming

So, evidently I failed to fulfill my ambition to blog regularly about the contents of my planned book on Patterns in Functional Programming.

My friend Alan Jeffrey passed away earlier this year.

My mentor, colleague, and friend Richard Bird died in April 2022 after a long battle with cancer.

The “Sieve of Eratosthenes” is often used as a nice example of the expressive power of streams (infinite lazy lists) and list comprehensions: That is, takes a stream of candidate primes; the head of this stream is a prime, and the remaining primes are obt…

I recently attended the Matthias Felleisen Half-Time Show, a symposium held in Boston on 3rd November in celebration of Matthias’s 60th birthday.

The previous post turned out to be rather complicated.

The previous two posts discussed arithmetic coding (AC).

In the previous post we saw the basic definitions of arithmetic encoding and decoding, and a proof that decoding does indeed successfully retrieve the input.

This post is about the data compression method called arithmetic coding, by which a text is encoded as a subinterval of the unit interval, which is then represented as a bit sequence.

In the previous post we were introduced to metamorphisms, which consist of an unfold after a fold—typically on lists, and the fold part typically a .