<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div>Shreevatsa -<br></div><div><br data-mce-bogus="1"></div><div>Excellent advice.</div><div><br data-mce-bogus="1"></div><div>Unfortunately, when one (well, me) builds a mental model of what's (not) going on, it gets in the way, bee-in-the-bonnet-wise, of how to devise the right scientific experiment to debug something.</div><div><br data-mce-bogus="1"></div><div>I don't write a lot of TeX source code. I just work to interpret it. :-)<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>- Doug Mck.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"Shreevatsa" <shreevatsa.public@gmail.com><br><b>To: </b>"doug" <doug@mathemaesthetics.com><br><b>Cc: </b>"Karl Berry" <karl@freefriends.org>, "tex-k" <tex-k@tug.org><br><b>Sent: </b>Friday, March 6, 2020 5:55:32 PM<br><b>Subject: </b>Re: [tex-k] Is this a bug or just an inconsistency?<br></div><div><br></div><div data-marker="__QUOTED_TEXT__"><div dir="ltr">You probably know this, but eTeX has a \tracingassigns=1 that would have helped debug here: for \def\csname\endcsname{FOOBAR} it prints<br><div>{changing \csname=\csname}</div><div>{into \csname=macro:\endcsname ->FOOBAR}<br></div><br><div>and for \expandafter\def\csname\endcsname{FOOBAR} it prints</div><br><div>{changing \csname\endcsname=undefined}</div><div>{into \csname\endcsname=\relax}</div><div>{changing \csname\endcsname=\relax}</div><div>{into \csname\endcsname=macro:->FOOBAR}<br></div><br><div>so you can see which macros are being set to what definitions. Something like this (maybe with some <a href="https://tug.org/TUGboat/tb35-2/tb110mckenna.pdf" target="_blank">changes</a> to the output format) is useful to have.</div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 6 Mar 2020 at 15:51, Doug McKenna <<a href="mailto:doug@mathemaesthetics.com" target="_blank">doug@mathemaesthetics.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Karl -<br>
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Yes, I think that answers the question (i.e., it's my misunderstanding).<br>
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So it's treating |\endcsname| as a delimiting matching token for the macro's (non) argument collection.<br>
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Ah, TeX. It's amazing how one can write TeX code that seems to make complete sense, yet have it mean something entirely different.<br>
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Thanks!<br>
<br>
- Doug McK.<br>
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----- Original Message -----<br>
From: "Karl Berry" <<a href="mailto:karl@freefriends.org" target="_blank">karl@freefriends.org</a>><br>
To: "doug" <<a href="mailto:doug@mathemaesthetics.com" target="_blank">doug@mathemaesthetics.com</a>><br>
Cc: "tex-k" <<a href="mailto:tex-k@tug.org" target="_blank">tex-k@tug.org</a>><br>
Sent: Friday, March 6, 2020 4:18:42 PM<br>
Subject: Re: [tex-k] Is this a bug or just an inconsistency?<br>
<br>
\def\csname\endcsname{FOOBAR}<br>
<br>
Do you mean<br>
\expandafter\def\csname\endcsname{FOOBAR}<br>
? I think the above is redefining \csname, not the null CS.<br>
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