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From: eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout)
Newsgroups: comp.text.tex
Subject: Re: [OzTeX] ^^M^^M not the same as \par.
Message-ID: <1991Mar29.200048.14404@csrd.uiuc.edu>
Date: 29 Mar 91 20:00:48 GMT
References: <1991Mar28.071310.26773@basho.uucp>
Sender: news@csrd.uiuc.edu (news)
Organization: UIUC Center for Supercomputing Research and Development
Lines: 55

john@basho.uucp (John Lacey) writes:

>I have a problem with OzTeX 1.3.  If I say `\def\foo#1\par{...}',
>and then say `\foo text\par', I get #1 as four tokens, `t', 
>`e', `x', and `t'.

How would you want it otherwise? There are two kinds of
tokens: character tokens and control sequence tokens
(oh well. parameter tokens is the third kind),
and you didn't say \foo\text\par, so you get four
character tokens.

>BUT, if instead I say `\foo text^^M^^M' (either just like that 
>or by actually pressing two returns), I get five tokens---the 
>obvious four and a trailing blank space.

Now I think you're holding something back here.
If you write 
\foo text^^M^^M
\nextmacros....
\againsomehting
\par
you will get 
#1 <- text \nextmacros\againsomething
so I suspect that you left an empty line after the
^^M^^M call.

Explanation: the first ^^M is the end of the line so the
second one is never seen.

Contrary to popular misconceptions, a \par is not the
result of two ^^M's in a row, it is the effect of
an ^^M while TeX is still in state N, that is,
if there were at most space characters on the line
so far.

Exercise for the reader: do you get a \par in the following
cases:
---
\space
---

---
\expandafter\relax
\space
---

---
\catcode`Q=10
Q
---

???

Victor.