Simon Willison’s Weblog

Closures and continuations

3rd April 2003

Thanks to Dan Sugalski (designer of Parrot, the next generation Perl VM) I finally understand what continuations and closures actually are. He explains them as part of a comparison between the forthcoming Parrot and two popular virtual machines already in existence:

1. (Perl|python|Ruby) on (.NET|JVM) leads in to the explanation.
2. The reason for Parrot, part 2 explains closures.
3. Continuations and VMs explains continuations.
4. Continuations and VMs, part 2 rounds things off by explaining why the JVM and the CLR are unsuitable environments for supporting these language features.