NXTalk: dynamic object-oriented programming in a constrained environment

Dynamic programming languages offer high expressiveness and flexibility, improving programmer productivity. Still, making dynamic programming languages available for embedded systems is challenging because such environments are often constrained in terms of memory or computational power. For this, it is necessary to reduce the size of language implementations (virtual machines, VMs) while at the same time retaining good performance and robustness. Automatic memory management deserves special attention because its performance and space overhead have noticeable impact on overall system usability. In this paper, we present NXTalk, a VM and programming environment for the Smalltalk programming language, making high-level object-oriented programming available on Lego Mindstorms NXT robots. We describe its VM implementation and evaluate its size and performance characteristics.