RE: [Expectperl-discuss] parsing non-ascii char's

[BLACKSTONE, J. D. <jda...@ci...>]

> -----Original Message-----
> From: Christian Goetze [mailto:cg...@hq...] 
> Sent: Tuesday, April 08, 2003 2:22 PM
> To: exp...@li...
> Subject: Re: [Expectperl-discuss] parsing non-ascii char's
> 
> 
> > Thx for your suggestion and I can see some merit here.
> > I am, however, starting to think I am off topic for this list.
> >
> > My real problem is that I do not have multiple lines of
> > data to parse. It's all one long line with lots of
> > control chars.
> >
> > When I print the data to a file
> >   cat <filename>
> > shows output that looks just like my telnet session.
> >   cat -v <filename>
> > shows all the ugly special chars
> >   wc -l <filename>
> > shows I have one line of data and
> >   cat <filename> | wc -l
> > still tells me I have one line of data.
> 
> What you need here is a terminal emulator. If you're really 
> unlucky, the other side will optimize redraws and you will 
> not easily get the correct picture. As a first step, you 
> could simply try ignoring the special chars, but you may end 
> up having to emulate the screen and do "screen scraping".

  I have had to do some of that and it was not fun.  Two things that might
help you:

  If you capture your session to a file, write a program to "play it back"
as a "movie" by clearing the screen and sending each character to the screen
in sequence with a small delay in between (like 0.1 seconds).

  The terminal garbage may likely include codes that position the cursor.  I
think in my case those codes were something like escape, control-[ , row,
semicolon, height, control-G.  Or something awful like that; I can't
remember what.  But I could parse out the row and column and use it.  I
wrote a program to take a cut and paste terminal screen capture and print it
out with - and | characters, with row and column numbers at the top and
bottom.  I made printouts of these to see where my data displayed, and
checked the session capture log to make sure the row and column appeared
exactly in the control garbage.  Watching the movie also became important
because sometimes things did not print out on the screen in the order you
would expect.

  It would theoretically be possible to write a program that maintained an
80x24 "screen" array of characters, read the control codes, and updated the
appropriate places in the array.  If you do, put it on CPAN!!!  But I didn't
find it necessary.

jdb