Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uunet!snorkelwacker!bloom-beacon!SHAMASH.MCRCIM.MCGILL.EDU!mouse
From: mouse@SHAMASH.MCRCIM.MCGILL.EDU (der Mouse)
Newsgroups: comp.windows.x
Subject: Re:  X11R4 xterm twists: PageUp/PageDown, Sun4 Numeric/Keypad, etc.
Message-ID: <9007230603.AA02011@shamash.McRCIM.McGill.EDU>
Date: 23 Jul 90 06:03:13 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 22

> We add wrapped-newlines, control-carats, and space-in-tab codes to
> the existing display codes [...].

The wrapped-newlines and space-in-tab are reasonable; the control-^
sounds reasonable but isn't.  The reason it isn't is that it's printed
to the pty as hat-plus-letter, unlike the others.  That is, xterm can't
tell whether that ^-followed-by-E is supposed to be a control-E or not.
A tab is received by xterm as a tab, and xterm chooses to display it as
some number of spaces; wraps are generated internally anyway.  But a ^E
representing control-E will be received by xterm as ^-plus-E, not as a
control-E character, hence the problem.

There's another problem with tabs: they are generally not destructive.
For example, the "foo^^^^^bar"->"foo  x  bar" example could just as
well be sent to xterm as "     x\rfoo\tbar" (to use the C conventions)
instead of the "foo\tbar\r\33[5Cx" we have been assuming.  (Or
something like that; the details are irrelevant.)

					der Mouse

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