memchan is an  extension library to the script language  tcl, as created
by  John Ousterhout.  It provides  two new  channel types  for in-memory
channels and the appropriate commands for their creation.

They are useful to transfer large  amounts of data between procedures or
interpreters, and  additionally provide an easy  interface to on-the-fly
generation of code too. No need to set  or append to a string, just do a
simple puts.