[XeTeX] unexpected DVI command: -1

[Jonathan Kew]

On 3 Sep 2004, at 5:36 pm, Bruno Voisin wrote:

> I have just been faced with this very same message for the first time, 
> straight after downloading and installing v0.85. I worked on a reduced 
> test case, for which the console output gets as short as this:

Bruno, with your reduced test file, I get the same crash with 0.84 as 
0.85, so at least it doesn't seem to be related to the update. (Which 
is a relief, as I haven't touched anything remotely related to this!)

> The error seems to be absolutely unrelated to the exact content of the 
> file TeXwise: the file compiles OK in LaTeX; switching to XeLaTeX, I 
> get the above error. If I comment out everything in the file starting 
> from a certain point, XeLaTeX'ing goes well; if I start commenting out 
> ten characters further, with only 7-bit ASCII Roman letters and a "," 
> in between, I get the error.
>
> There only seems to be one thing systematic about this error: it 
> happens only with the default CM/AMS fonts. If I switch to any other 
> font for text, for example by selecting Trebuchet MS as I reported 
> earlier on this list, all goes well; if I use the LaTeX packages times 
> or lucidabr, similarly, to switch to the Times or Lucida 
> Bright/NewMath fonts, all goes well too (except that I can't see the 
> characters in the output, XeTeX having no access to fonts in .pfa 
> format).

I believe this crash is happening during the second pass over the 
paragraph, when TeX looks for hyphenation points. Changing fonts or 
modifying the text content may cause it to go away, as the paragraph 
might not need hyphenation at all; I'm pretty sure that it *could* 
happen with other font packages such as times or lucidabr, you just got 
lucky in this case!

(Using an AAT or OpenType font might be a whole different situation, as 
these are handled differently inside xetex, and the hyphenation routine 
is working on different structures.)

Obviously, I didn't *intentionally* change anything about the standard 
paragraphing routines when working with TFM-based fonts, but my work to 
incorporate AAT/OT font support must have broken something under 
certain circumstances. I'll be looking into it, though it may be a few 
days.

Thanks for the reports, guys, and sorry about the trouble!

JK