Re: Control chars during an escape sequence

[Thomas Dickey]

On Wed, Aug 07, 2019 at 10:23:07AM +1000, Tim Allen wrote:
> On Tue, Aug 06, 2019 at 06:02:35PM -0500, Bryan Christ wrote:
> > The reason I ask is because the the string which accompanies the OSC
> > "set window title" sequence is often terminated by 0x7 (bell) so that
> > seems to be an issue. In the "vttest" scenario, only "backspace" and
> > "vertical tab" are injected into the escape string. Is that because
> > they're the only two that are permissible?
> 
> The vt100.net state diagram[1] says that all control characters inside
> an OSC sequence are ignored, except for ESC (which starts a new
> sequence), CAN, and SUB (which are both "executed", and I think cancel
> the sequence). On the other hand, it doesn't say anything about BEL
> executing the sequence, only ST (0x9C).

something like that - the C0 and C1 codes are different cases,
as noted in a comment at the bottom of the picture.  In xterm,
that's the sos_table, which has non-ignore codes for half of the C1 range.

Paul Williams gave advice/fixes a while back, and I've added runtime
checks in xterm to help avoid breaking symmetry where it _should_ be preserved.
 
> [1]: https://vt100.net/emu/dec_ansi_parser
> 

-- 
Thomas E. Dickey <address@hidden>
https://invisible-island.net
ftp://ftp.invisible-island.net

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