I lack the skills to do this (at this time), but I think it would be very
useful.

I would like a widget that displayed scrolling text. Configurable parameters
are:

The number of lines of text to display.

The number of lines of text to save (can scroll back to).

The width of a line in characters (should scroll sideways or possibly wrap
if exceeded).

The name of a file to read the text from. The widget should do the
equivalent of a 'tail' on this file. That is, it should keep a read pending
on the file and add whatever lines it reads to the bottom of the display. In
use, the file will actually be a named pipe.

The general use for this widget will be as a way for the interpreter to
generate output for the user. The interpreter will be modified to provide
debugging information to the user. For instance, it will be possible for the
user gcode to have embedded "print" statements. (They exist already, but use
the msg facility which is only good for a line at a time and which Axis
requires the user to clear.) When an error occurs, the line number, the last
line, and a subroutine traceback can be generated. Changing the interpreter
to write this to a named pipe is trivial.

One downside of this method is that only a single interface at a time would
be able to read the named pipe. You couldn't run two interfaces and have
them both display this information. There are many advantages of this over
using shared memory, though. (1) Messages transmission is synchronous. There
is no polling by the display interface to see what is there. The display
interface has a thread that just waits for data and displays it when it
arrives. (2) The display application is unaware of any structure associated
with the messages. It just displays them. (3) There is no shared memory
allocation or destruction. A named pipe looks like any other file in the
file system. It is created by 'mkfifo pipename'.

The next thing I might ask for is a way for a button to write to a named
pipe, although I suspect that we can do what I want using HAL. The idea is
that the gui will be able to set flags saying single step, step over, step
through, breakpoint, and so on to let us build a debugging interface to the
interpreter.

Your help would be appreciate. [Also, you can tell me I'm all wet and
suggest a better way. Or a different way.]

Thanks,

Ken



[EMAIL PROTECTED]
Mark Kenny Products Company, LLC
55 Main Street                     Voice: (203)426-7166
Newtown, CT 06470                    Fax: (203)426-9138
http://www.MarkKenny.com

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