Streamulus, written by Irit Katriel, uses very clever template meta-programming (via Boost Fusion) to implement an embedded domain-specific event language created specifically for event stream processing.
The packages wraps the four existing examples by Irit, all her unit tests and includes a slide deck from a workshop presentation. The framework is quite powerful, and it brings a very promising avenue for (efficient !!) stream event processing to R.
The NEWS file entries follows below:
Changes in version 0.1.0 (2015-01-30)
First CRAN release
Contains all upstream examples and documentation from Streamulus
Added Rcpp Attributes wrapping and minimal manual pages