[tex-eplain] btxmac.tex causes Runaway definition and Forbidden control sequence on compile.

[Laurence.Finston at gmx.net]

You have to include btxmac.tex before you include eplain.tex. I just tried this out and you get the error if you include eplain.tex first and you don't if you include btxmac.tex first.

At the beginning of btxmac.tex (/usr/share/texlive/texmf-dist/tex/eplain/btxmac.tex on my system), there is
a long explanation of how to use it. I don't use BibTeX so I don't know anything more about it.

> \beginpackages
> \usepackage{url}

I don't know about this. Is this defined in (plain) TeX when using eplain? It's correct for LaTeX but if one wants to use packages (and LaTeX syntax), I think one might just as well use LaTeX.

For hyperlinks, either of these commands suffices:
\enablehyperlinks[pdftex]
\enablehyperlinks[dvipdfm]

I often add this: \hlopts{bwidth=0}

Then, for the links, for example:

\hlstart{}{bwidth=0}{instructions}\Blue{General Instructions}\hlend
[...]
\hldest{fit}{}{instructions}


> Gesendet: Dienstag, 10. Oktober 2023 um 08:22 Uhr
> Von: terry.s at Safe-mail.net
> An: tex-eplain at tug.org
> Betreff: [tex-eplain] btxmac.tex causes Runaway definition and Forbidden control sequence on compile.
>
> Hello,
>
> I have TeX Live 2022 installed on Windows 10, and am learning TeX and eplain.
> If I try to compile a (previously fine) document with 'btxmac.tex' loaded, I get a "Runaway definition" error.
> I believe the problem is in the source of 'btxmac.tex' for 3 reasons:
>
> 1) It compiles fine without it.
> 2) The error references macros I don't have in my document (including some with '@' and '@@').
> 3) The error references "L. 357" but my source barely tops 200 lines. (The example attached only has 18.)
>
> Below are error and *minimal example* source (which I will also attach):
>
> **Error**
> This is TeX, Version 3.141592653 (TeX Live 2022) (preloaded format=tex)
> (./eplain-01.tex (c:/texlive/2022/texmf-dist/tex/eplain/eplain.tex)
> (c:/texlive/2022/texmf-dist/tex/eplain/btxmac.tex
> Runaway definition?
> [#1]->\def \@optionalarg {#1}\let
> ! Forbidden control sequence found while scanning definition of \@@getoptionala
> rg.
> <inserted text>
> }
> <to be read again>
> \@optdummy
> l.357 \let\@optdummy
> =\relax % just in case it has become \outer somehow
> ?
>
> **Example TeX Code**
> \input eplain
> \input btxmac.tex
> \beginpackages
> \usepackage{url}
> \endpackages
> \enablehyperlinks
> \parskip=\baselineskip
> % SHORTCUTS + CUSTOM DEFINITIONS (retained in case they contribute to error):
> \def\footnote{\numberedfootnote}
> \def\bslash{$\backslash$}
> \def\mycmd #1{{\tt\bslash#1}}
> \def\startnoskip{\bgroup\parskip=0pt}
> \def\endnoskip{\egroup}
> \def\mysep{\vskip2pt\centerline{$ˆ{\vrule width2cm height .5pt}$}\vskip2pt\noindent}
>
> \beginsection Minimal Example (with eplain, btxmac.tex and url)
> Hello there!
> \bye
>