[tex-eplain] Can't use nor define my own "newlinechar"

[terry.s at Safe-mail.net]

Thank you for the explanation. (^^J is character 10 = Omega in Computer Modern). Petr Oslak shows \nl in the documentation for OpTeX ... but searching the Eplain PDF nothing is found. So it is hopefully safe to define it here? I was thinking a /nl would be eminently safe (I can't think of an "and/or" phrase in English that would include "/nl"), but would it work, not being a control sequence?

I'm not on Linux at the moment. I have Puppy installed on my computer (still), because it's so dependable with computers of all ages, depending on the "flavor", but I have TeX Live installed on Windows 10. I edit with *EditPad Lite* except for TeX (TeXworks), C++ (Dev C++) and Python (either IDLE or SciTE).

-------- Original Message --------
From: Laurence.Finston at gmx.net
Apparently from: tex-eplain-bounces+terry.s=safe-mail.net at tug.org
To: tex-eplain TUG <tex-eplain at tug.org>
Subject: Re: [tex-eplain] Can't use nor define my own "newlinechar"
Date: Thu, 12 Oct 2023 22:35:18 +0200

> J is the tenth letter in the alphabet and Control-J, or ^^J in TeX, is a way of representing the non-printing ASCII characters, which refer to commands for teletype machines;  a device no home should be without.  ASCII 10 is the newline command (or character).  You can confirm this in emacs by typing ?[Cntrl-J], which will put a newline in your buffer.  Then type C-xe, or whatever key sequence is bound to the function eval-last-sexp and you will see this in the mini-buffer:  10 (#o12, #xa, ?\C-j)
> 
> Capital Omega is character 10 in Computer Modern Roman.  If you use a sequence defined to mean "character 10", it will cause character 10 in the current font to be typeset.
> 
> > I'd really like to make \nl the newline character
> 
> \def\nl{\hfil\break} does what I think you want.
> 
> As far as I know, the newline character is only for output with \write and \message.  I believe the character that tells
> TeX that a line of the input has ended is 13 [RETURN] but TeX reencodes every character it reads so it is independent
> of ASCII, EBCDIC or any other encoding.  I think _The TeXbook_ explains this.  Otherwise, it's in _TeX:  The Program_.
> 
> > The thing is, the *eplain* documentation says this is ALREADY defined as ^^J, but it's not. And using \show reveals it has some sort of circular definition to itself! (Maybe I don't understand the terminal output in this case.)
> 
> It shows that \newlinechar is a primitive.