Stateless Tests in a Stateful Protocol

January 25th, 2010

Lets suppose you want to test the correctness of a protocol. I know I do, all the time; get me that input fuzzer. A typical way to start might be a minor variation on how I learned to test my code in CSE 142 and hadn’t really thought too much about since: plug in some “representative” values and see if it does the right thing. But let’s suppose someone came over with a pile of documentation and said “Here. Some genius in the back room made this insanely complex server that apparently speaks this protocol, and somehow managed to do it without so much as a single unit test. Can you test it? By the way, we want some guarantees about security.”

The Many Flavors of Curry

August 31st, 2009

Many functional languages have this nifty feature called ‘currying’ or ‘curried functions’. The name comes from the logician Haskell Curry (son of Samuel Silas Curry — someone please hook me up with wherever they are getting these names!), for whom the Haskell programming language is also named. Currying is a technique for making partial applications of functions first class objects in an intuitive way.

Gems in Scheme

July 27th, 2009

One sometimes hears that call-with-current-continuation is useless or pointless. Such things have come from the Python developers, and while Ruby 1.8 had a call/cc method, it’s not clear if it will survive in the next major release, allegedly because it’s “useless” or “too expensive”.

In fact, I tend to think that in fact, these developers simply don’t understand what call/cc is about or why it is valuable. So I’ll show some examples.

This Part 1 of our Gems in Scheme series