Trf is an extension library to the script language Tcl,
as created by John Ousterhout. It provides transformer procedures
which change the flow of bytes through a channel in arbitrary ways.
The underlying functionlaity in the core is that of ''stacked channels
which allows code outside of the core to intercept all actions
(read/write) on a channel.
Among the applications of the above provided here are compression,
charset recording, error correction, and hash generation.
The latest release of the extension is version 2.1.4 as of October 26, 2009.