VPWEDIT

VPWEDIT is an EDT V3.0 front end and tries to exactly emulate the distributed
EDT and provide WINDOWS.  It uses the XLATE function of EDT and a bunch of
rather fancy footwork with SYS$VPWFILES:WINDOW.COM.  When F20 (VT2xx in
VT200 mode) or GOLD V on VT1xx terminals is pressed (key definitions must
be part of EDTSYS.EDT), EDT spawns an @SYS$VPWFILES:WINDOW the first time
it is invoked.  WINDOW.COM displays a window banner, sets up a scrolling
region, and prompts for input.  Control-Z exits the window back to
EDT (Attaches back to main process) but leaves the subprocess ready for more
action.  A LOGOUT deletes the window and returns to EDT.  Subsequent
invocations of the WINDOW command first try to attach to the previous
subprocess.  If successful, WINDOW.COM again starts up, displays a header
and prompts.  If unsuccessful, EDT spawns a new process and proceeds
as it did the first time.

As stated above, WINDOW.COM does a lot of fancy footwork.  After each
command it finds out where the cursor is sitting so that it can return
there (but only within the scrolling region) to the right spot after 
repainting the banner.  In the previous release, typeahead was not 
supported because it is a tad bit tricky to get a command procedure
to distinguish between the terminal response to a "where are you cursor"
command and asynchronously input user input.  Also, emulating the
above in a command procedure slows things down.   Well, my users loved
windows but bitched about missing typeahead.  

So, after some sole searching, much head scratching, and after
putting on my little spiked hat with the stars and funny symbols on 
it, I came up a command procedure which "supports" typeahead emulation.
So far, it looks like the emulation works.  Now because the 
typeahead is saved in an internal buffer (not terminal buffer), if one
makes a mistake, typing a ^U will not flush the buffer.  Rather one can
press the REMOVE key on VT2xx terminals in VT2xx 7-bit mode or ^Y on other
terminals to flush the buffer as it is prompting for the rest of the line. 
You know when it is ready and prompting because the "$" prompt appears with
any typeahead characters following it. Note, however, that when in window
mode, continuation lines are not supported (and easily lead to chaos) and
that quotes are bad news and lead to even grater chaos.  However, all else
is great and works just like a VTxxx terminal with a 20 line screen (albeit
a tad bit slower).  Users not liking the banner (etc.) can speed up things
considerably by removing the banner generation code in WINDOW.COM. 

As a side benefit VPWEDIT also provides a CLIPBOARD function. I am not
satisfied with the way this function works, so it may or may not be present
in subsequent versions of VPWEDIT.  At present, I am keeping the
functionality a secret from my users.  The reason for this is that it is
easy to get into a terminal lockout situation requiring the process to be
stopped.  This can happen if you request a DCL function with output to go
to the CLIPBOARD which does not terminate (ie not SHOW PROCESS/CONTINUOUS).
Subprocesses spawned with /WAIT have Control-Y disabled for the main
process while the subprocess executes. 

The EDTINI files EDTSYS.EDT (EDTSYSSLO.EDT for dial-in terminals) should be
placed on SYS$SHARE:.  On VT2xx terminals in VT2xx mode, F20 activates the
window.  On VT100 terminals GOLD Control-V does the same.  The clipboard is
activated by GOLD Control-D (at present, no commitment to the future). 

Ideas for improving VPWEDIT are welcome.  Until then.... Enjoy!