Functional optimizations with PyPy

A wickedly clever idea for Python, from Christopher Armstrong:

If you think that's crazy, you can also take a look at Use-Once-Variables, an idea for adding "linear objects" to non-linear languages (pretty much all programming languages are non-linear). Use-once-variables refer to linear objects, which can only ever have one reference at a time. Copying and deletion both require explicit support from the linear object. It definitely changes your style of programming to use linear objects, but they can offer some serious improvements to the ability to reason about code that uses them, not to mention that you can optimize the crap out of them.

Henry Baker, author of the paper that Armstrong cites, also inspired the excellent Chicken Scheme implementation. His work would make good rainy-day reading, one of these rainy days.