+To exit, enter ^D on a blank line or use the `BYE` word.
+
+## FORTH-83 Compliance
+
+One of my goals has been to have forth.jl contain as much of the
+[F83 required word set](http://forth.sourceforge.net/standard/fst83/fst83-12.htm)
+as makes sense given the underlying VM. (Actually, my main goal goes a bit
+beyond this: I want to be able to, with a couple of exceptions, be compatible
+with the description of forth contained in the second edition of Leo Brodie's
+book "Starting Forth".) I'm fairly happy with my progress so far. Of the
+131 required F83 words, only 20 remain unimplemented. These words fall into
+two categories: those I may possibly implement at some point, and those that I
+do not intend to ever implement for reasons of obsolescence or incompatibility
+with the design of the VM.
+
+### F83 Words that may be implemented someday
+
+ # #> #S -TRAILING <#
+
+These words all have to do with number to string conversion, something I've
+not been interested in enough yet to get on top of.
+
+### F83 Words that won't be implemented
+
+ D+ D< DNEGATE U< UM* UM/MOD BLOCK BUFFER FLUSH
+ SAVE-BUFFERS UPDATE BLK HOLD LOAD FORTH-83
+
+These words don't make sense to implement. The double-length integer words are
+useless because the smallest unit of memory in our VM is a full 64 bit
+integer. For the same reason, there's no point in dealing with unsigned values
+just to gain access to another bit. The block I/O words don't make sense because
+we have access to a filesystem via the OS.
+