Nock is a stateless virtual machine defined in 200 words. The Nock machine is sealed - all execution is “pure.” Nock’s goal is extreme commoditization of computing semantics.
Hoon is a high-level language which defines itself in Nock. Its self-compiling kernel, 7000 lines of code, specifies Hoon unambiguously; there is no Hoon spec. Hoon can be classified as a pure, strict higher-order static type-inferred functional language, with co/contra/bivariance and genericity. However, Hoon does not use lambda calculus, unification, or other constructs from “PL theory.” Hoon also excels at handling and validating untyped data, a common task on teh Internets. Its syntax is entirely novel and initially quite frightening.
Arvo is a deterministic functional operating system defined in Hoon. While still basically a toy, it can serve web apps and network securely with other Arvo instances. An Arvo instance is designed to be a simple independent computer in the cloud.