Re: Terminal emulator in Windows

[Jim Porter]

On 1/11/2023 10:26 AM, Akib Azmain Turja wrote:
> Jim Porter <jporterbugs@gmail.com> writes:
>
> > On 1/11/2023 1:35 AM, Akib Azmain Turja wrote:
> > > In general, is it possible to implement Windows terminal emulation?
> >
> > Do you mean "emulating cmd.exe" or "emulating a terminal and running
> > that emulator on MS Windows"? The former might be trickier, and I
>
> I started the thread, and even I don't know.  But I guess the latter.
> For more information, you may check the Eat issue 35 on Codeberg:
> https://codeberg.org/akib/emacs-eat/issues/35

In some ways this issue actually sounds more like the former. It sounds 
like the user wants something like ConEmu[1] in Emacs. ConEmu's 
implementation seems pretty hacky to me, since it relies on an invisible 
Windows Console window[2].

On the other hand, there's the new-ish MS Windows API called ConPTY (as 
the name implies, it gives you a pseudoterminal). This would give us 
similar benefits compared to what ConEmu does, but using an 
explicitly-supported API for it. This would be nice, since then Emacs 
could just use pseudoterminals everywhere, which I think is what we 
want. Unfortunately, it seems that this API isn't suitable for Emacs, as 
discussed here[3] by Eli.

> > haven't really looked into how you'd do that. However, the latter
> > might just mean handling VT100 terminal sequences, which I don't think
> > would require knowing about any Windows-specific features/APIs.
>
> But somehow we need to tell the program what escape sequences to send,
> don't we?

From this discussion[4], it's the *program* that decides to opt in to 
sending VT100 sequences to a Windows console. That is, if I wrote a 
cross-platform program that uses VT100 sequences, I'd call 
'SetConsoleMode' with 'ENABLE_VIRTUAL_TERMINAL_PROCESSING' in my MS 
Windows port. Maybe Emacs could piggyback off of that.

I don't know if this would help solve the issue in the bug you linked, 
but maybe something like this would work for handling VT100 sequences in 
Eshell via 'eat-eshell-mode', or when running *nix programs remotely 
through Tramp.

[1] https://conemu.github.io/

[2] https://conemu.github.io/en/RealConsole.html

[3] https://github.com/microsoft/terminal/issues/9174

[4] https://news.ycombinator.com/item?id=25866634