
		       Stem::TtyMsg Design Notes

The Stem::TtyMsg is a class Cell which provides a simple command line
interface to a Stem Hub. It parses lines typed into stdin and creates
and dispatches command type Stem Messages from them. It also can accept
and print response messages sent back by the command method in the
addressed Cell.

This class Cell is registered under its class name and with the nickname
'tty'. It must be configured to initialize it but it takes no
configuration arguments. Its 'new' method just creates an Stem::AsyncIO
object to handle I/O to and from stdin and stdout and doesn't return an
object.

Command lines entered are parsed very simply. The first token must have
a colon (:) which separates the Hub and Cell name. The Hub name is optional
and the Cell name is required. The next token is the command of the
message and it will cause this message to be delivered to a command
method of the addressed Cell (or the 'msg_in' method if the command
method is not found). The rest of the line is sent as the data part of
the message.

If the command method returns any data, the Stem Messaging subsystem
will automatically create a response message and send it back to this Cell.
The data of the response message will be printed to stdout.
