[Info-vax] macOS Terminal app. Numeric keypad fails for EDT.

[Johnny Billquist]

On 2022-09-24 21:36, alanfe... at gmail.com wrote:
> On Saturday, September 24, 2022 at 11:38:53 AM UTC-4, Johnny Billquist wrote:
>> On 2022-09-24 05:13, alanfe... at gmail.com wrote:
>>> On Friday, September 23, 2022 at 4:34:55 PM UTC-4, Johnny Billquist wrote:
>>>> On 2022-09-23 21:16, Michael Moroney wrote:
>>>>> On 9/22/2022 5:06 PM, alanfe... at gmail.com wrote:
>>>>>> The only problem I have with Terminal is that using EDT in full-screen
>>>>>> mode wipes out part of the history buffer (not the commands, but
>>>>>> screen output).
>>>>>
>>>>> I noticed something like that with iterm2, not elsewhere, I'll look at
>>>>> EDT to see what's up.
>>>> Not sure what you are referring to. EDT clears the screen in order to
>>>> draw whatever it wants to show there. So of course, whatever else was
>>>> there before is gone.
>>>>
>>>> Or are you referring to something else?
>>>>
>>>> Johnny
>>>
>>> Say I run SHOW SYSTEM on EISNER. It's like a hundred-something lines. Say it's 160 lines. I run EDT. It clears the screen, brings up the file, I do my edits, and exit. Now I page-up to review the SHOW SYSTEM output, and the l last 30 or 40 or whatever lines are gone. If I had instead run, say, SH DEV DS, I get what,10 lines of output? Then I do a full-screen editing session. Then I page-up to see the SH DEV DS output again, and it's gone. Older stuff is still there, but the last n lines of what was there before I edited something is gone for good. Maybe you never do the page-up bit to see previous commands and their outputs.
>> The last 30-40 lines (the screen size I would guess) would be gone,
>> since those lines were reused by EDT. Anything that was off the top of
>> the screen are no longer active, and can't be overwritten, so they stay
>> around.
>>
>> On newer terminal emulators, there exists an escape sequence to switch
>> to an alternative window, which some applications use, so that all
>> current screen content remains. I highly doubt EDT knows about, or uses
>> that escape sequence. But I have a feeling that is what you are thinking
>> of/hoping for. Some other, newer editors, would be using that when possible.
>>
>> A real VT terminal do not have that alternative window, so it's
>> something that DEC never played with.
>>
>> Johnny
> 
> Yep, it works fine with TPU. One then needs to put it in a DCL jacket with the right secret escape sequence, or get one of these newfangled terminal emulators.

You need both a new fangled termina emulator, *and* an editor which 
switches to this alternative screen.

A little surprised TPU knows about it, but I guess maybe because of 
xterm and the VXT terminals, it already was around in the later days of 
DEC software?

   Johnny