FlightAware has released the SpeedTables package for Tcl, which basically creates C structures on the fly, as well as C-based accessor routines:

"Speed tables reads a structure definition and emits C code to create and manipulate tables of rows of that structure. This allows operations to be performed on the table at native code speeds, using a custom extension that manages rows of fields as native C structs and emit subroutines for manipulating those rows in an efficient manner."

FlightAware.com deals with extremely high-volume data throughput, and they manage the whole process with Tcl.

https://github.com/flightaware/speedtables