Spilornis is part of the Eagle project.
It is a utility library that implements the Tcl list splitting and joining algorithm in native code.
It is fully Unicode (UCS-2 / UTF-16) aware, is based on the official Tcl sources, and may be used by any project.
When optionally enabled for use by the core Eagle library (i.e. managed code), a couple things will occur:
The source code can be seen at Eagle Native Utility Library (Spilornis)