What's RHDL? Ruby Hardware Description Language, or maybe more accurately, 
Ruby as a Hardware Description Language.

What's an HDL: Hardware Description Languages are used to describe and 
simulate hardware components.  The two main HDLs used by hardware 
engineers are VHDL and Verilog.  In recent years the trend has been to 
adapt general purpose programming languages for use as HDLs (JHDL [Java 
HDL], System-C [an HDL based on C++]) - perhaps RHDL could be seen as part 
of this trend, but mostly I created it for fun and to experiment.
HDLs have special requirements not typically seen in regular programming 
languages - things like concurrent signal assignments and processes that 
get launched when the value of a signal changes.

The code will be available soon at: 
http://www.aracnet.com/~ptkwt/ruby_stuff/RHDL

Again, I have to marvel at how little code this all required.  The 
original implementation of RHDL was done in 300 lines of Ruby.  I may have 
added another 200 lines or so since then, so it's still well under 1000 
lines!

Fixes since the last release:
- concurrent processes now work correctly(ie. you can now have a process 
which is 
sensitive to a signal that is changed in another process - it didn't work 
right before.)

TODO: 
- hierarchy.  Currently you can only define one design, I'd like to 
introduce hierarchy so you can define components which can be 
instantiated in other components.

Phil