[Aleph] Big in Aleph about \fam

[Benjamin BAYART]

Le Mon, Jan 17, 2005 at 12:53:22PM +0100, Giuseppe Bilotta:
> 
> > PS: I'm also looking around about a bug in the DVI files produced by
> > Aleph, but I don't have yet enough data about it.
> 
> I know of at least one case when the DVI produced is wrong
> (more pushes than pops or something like that), but I haven't
> been able to corner it to a minimal test case either.

I have a different case. It's related to a font with a lot of
kerning/ligatures. In a precise case: when a word in this font is
hyphenated Like that "Ac-clamation", the c in the beginning of the
second line produces a bug. TeX adds before the "c" the char coded 128.
Omega segfault. Aleph adds the char coded "257" in front of the "c".
There is no such character in the font. The good behaviour is the one of
TeX.

When the resulting file is viewed with xdvi, it crashes (cannot handle
chars >255). When viewed with oxdvi it complains about missing char in
the font. My guess is that the error is in chapter 40 of tex.web, in the
place about kern/ligature (the char 128 is involved in a ligature
between "c" and the beginning of line.

I do have an example that can reproduce the bug each time, but you will
need to have the font and so on.

Here is the test file frc.tex. The goal is to obtain an hyphenation in
the word "Ac-centue". I use LaTeX+babel to obtain french hyphenations,
but I guess it is not useful to reproduce the bug (it might be reduced
to a pure TeX document). I have no "aleph" format to test a "plain"
file.


\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage[frenchb]{babel}

\begin{document}

\font\fcr=frcc10
\hyphenpenalty=-100

\noindent long repousse tout doucement vers la gauche le texte qui
suit pour c\'esure \fcr Accentue les pleins.

\end{document}

A pure TeX example would look like that (with TeX it produces the
hyphenation, no way to check with Aleph on my system, with Omega
it produces the char 257):

\font\fcr=frcc10
\hyphenpenalty=-100

\hyphenation{Ac-cen-tue}

\hsize=8em

\noindent useless text here  \fcr Accentue les pleins.

\bye


If you need the file frcc10.tfm, I can provide it, of course.

Regards,

	Benjamin.