Re: JLine for VMS

From	cross@spitfire.i.gajendra.net (Dan Cross)
Newsgroups	comp.os.vms
Subject	Re: JLine for VMS
Date	2026-03-25 18:43 +0000
Organization	PANIX Public Access Internet and UNIX, NYC
Message-ID	<10q1abm$c8b$1@reader2.panix.com> (permalink)
References	<10pu8oa$10r0f$1@dont-email.me> <10pvg1j$1g49c$1@dont-email.me> <10q0esf$m74$1@reader2.panix.com> <10q0u0p$20cet$2@dont-email.me>

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In article <10q0u0p$20cet$2@dont-email.me>,
Arne Vajhøj  <arne@vajhoej.dk> wrote:
>On 3/25/2026 6:54 AM, Dan Cross wrote:
>> In article <10pvg1j$1g49c$1@dont-email.me>,
>> Arne Vajhøj  <arne@vajhoej.dk> wrote:
>>> On 3/24/2026 9:46 PM, Dan Cross wrote:
>>>> It looks like that's pretty deeply intertwined with the POSIX
>>>> termios interfaces.
>>>>
>>>> What, exactly, are you trying to do?
>>>
>>> There are several Java applications that use JLine.
>>>
>>> It would be nice to be able to run them on VMS.
>>>
>>> Not all of those applications need JLine for
>>> basic functionality, but still nice to have.
>
>> Looking at the documentation, this seems to be a mashup of what
>> curses and GNU Readline provide on Unix-like systems.  Curses
>> works on VMS, but JLine seems to want to reach into the
>> pseudo-terminal system and do everything itself.  Reading
>> between the lines, it probably creates PTY master/slave pairs
>> behind the scenes, using JNI.
>
>It is commonly used in cases where a tool needs to work
>in 3 ways:
>
>$ foobar whatever.db
>$
>
>and:
>
>$ foobar -c "..."
>$
>
>and:
>
>$ foobar
>fb> ...
>fb> ...
>fb> CTRL/Z
>$
>
>and the last needs some enhanced capabilities.

It seems rather more advanced than that.  It has a full terminal
manipulation subsystem baked in, complete with cursor position
handling and so on.  I don't know if they handle the row update
problem the way that curses does (most recent TUI libraries seem
to punt on it; practically no one is writing to a plain 'ol
serial terminal anymore: we're pretty much writing to little
windows on a screen driven by a bitmapped graphics adapter, so
"updating rows" is less intersting than just bitblt'ing images).

>> So if you'd like this to work on OpenVMS, you'll have to provide
>> either some sort of compatibility shim that looks like POSIX
>> termios, or reimplement those bits using native OpenVMS
>> primtives.
>> 
>> What I'd probably do is dig into the curses (or perhaps ncurses)
>> port and see what they do to bridge that gap, and then modify
>> JLine's JNI components similarly.
>
>Maybe.
>
>But my order of preference if I were to start on this would be:
>1) SYS$QIOW (QIO is not bad for terminal IO)
>2) SMG$ (haven't used it for 30 years but it is pretty solid)
>3) curses/ncurses (back in the days the VMS curses had a very bad
>    reputation, but maybe the Bill P ncurses is OK)

I don't see how that's significantly different than what I said.
I presume that the (n)curses ports to VMS use the native VMS
facilities, and don't try to pretend they talking to Unix.  The
point was to look at the implementation of the ncurses/curses
ports to see how they do work, and if there's anything useful
you can mine from them to port this JLine thing.

	- Dan C.

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Thread

JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-24 10:57 -0400
  Re: JLine for VMS Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2026-03-24 18:15 +0000
    Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-24 14:29 -0400
      Re: JLine for VMS "Craig A. Berry" <craigberry@nospam.mac.com> - 2026-03-24 15:13 -0500
        Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-24 16:34 -0400
      Re: JLine for VMS cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-25 01:46 +0000
        Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-24 22:07 -0400
          Re: JLine for VMS Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-25 04:40 +0000
            Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-25 11:02 -0400
          Re: JLine for VMS cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-25 10:54 +0000
            Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-25 11:12 -0400
              Re: JLine for VMS cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-25 18:43 +0000
          Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-25 20:40 -0400
            Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-27 12:41 -0400
              Re: JLine for VMS Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2026-03-27 18:18 +0000
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-27 14:41 -0400
                Re: JLine for VMS Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2026-03-27 18:54 +0000
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-27 15:12 -0400
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-27 15:14 -0400
                Re: JLine for VMS hb0815 <mw40171@mucweb.de> - 2026-03-28 21:39 +0100
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-28 17:33 -0400
                Re: JLine for VMS hb0815 <mw40171@mucweb.de> - 2026-03-28 23:25 +0100
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-28 21:24 -0400
                Re: JLine for VMS hb0815 <mw40171@mucweb.de> - 2026-03-29 12:34 +0200
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-28 21:27 -0400
                Re: JLine for VMS Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-29 03:19 +0000
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-29 10:13 -0400
                Re: JLine for VMS kludge@panix.com (Scott Dorsey) - 2026-03-29 11:05 -0400
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-29 15:51 -0400
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-29 16:03 -0400
                Re: JLine for VMS cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-30 01:39 +0000
                Re: JLine for VMS Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2026-03-30 12:25 +0000
                Re: JLine for VMS Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-29 22:44 +0000
                Re: JLine for VMS hb0815 <mw40171@mucweb.de> - 2026-03-29 12:41 +0200
                Re: JLine for VMS Arne Vajhøj <arne@vajhoej.dk> - 2026-03-29 08:03 -0400
                Re: JLine for VMS hb0815 <mw40171@mucweb.de> - 2026-03-30 10:50 +0200
                Re: JLine for VMS Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-29 22:46 +0000

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