Third SoCal Piggies meeting

The SoCal Piggies had their third meeting at USC on May 17th. A record number of 7 Piggies attended (Daniel, Howard, Mark, Grig, Brian, Titus, Diane), joined by a guest from Caltech. It was nice to meet Howard, Brian and Mark and to talk about Python while munching on a fairly decent Pizza Hut nourishment.

Titus Brown presented part 2 of his Quixote 2.0 tutorial. He showed a few introductory examples, then delved into more advanced stuff, showing how to manage sessions with Quixote. One thing I took away from it is that it takes remarkably little code. Generally speaking, Quixote seems very crisp and clean, and Titus' tutorials are very good in smoothing the learning curve, which can otherwise be steep.

Titus then spent some time talking about his Web app. testing tool twill. We couldn't get a live demo unfortunately, but it was an interesting discussion nevertheless, covering things such as the cmd module, pyparsing, and especially a great use of metaclasses. Titus ended his presentation talking about his Cucumber module, another magical metaclass-heavy module that provides a mapping between Python code and SQL statements, hiding the complexity of SQL away from the programmer.

Daniel Arbuckle was next, and he gave us an overview of iterators, generators and continuations. He highly recommended the little-used itertools module, which provides functions designed to work with iterators. The functions are similar to standard Python built-ins like map and range and allow you to write code that is faster memory-efficient. Daniel then covered generators, which can be seen as a way to express iterators using functions as opposed to classes (if you see a yield statement anywhere in a function, that function is a generator). However, there are many other and sometimes slightly brain-melting uses of generators, such as cooperative multitasking and state machine control.

Daniel ended with a mind-boggling discussion of continuations, which (luckily or unluckily?) are not and will not be offered as a feature of Python, due to GvR's dislike of them. Especially interesting was the parallel Daniel made between continuations and the HTTP GET mechanism.

Many thanks to Titus and Daniel for their presentations.

The next meeting will be at USC again, on a date to be announced. Topics for next meeting:

• CherryPy tutorial (if Greg McClure will be able to attend the meeting)
• SimpleTAL and Pyrex tutorials (Diane)
• Others?