Hi all,

I'm working with some code that was developed by someone else.
The document I'm typesetting is now giving the following error:

! Missing number, treated as zero.
<to be read again>
                   \otr:1:27
\OTRSETdoifcellelse ...er #1:\number #2\endcsname
                                                  \@EA
\secondoftwoarguments...

\@@ar@@1 ...ellelse {\mofcolumns }\columnlastcell
                                                  {\global \advance
\columnl...

\redoloop ->\expandrecursecontent
                                  \endofloop
<to be read again>
                   {
<inserted text>
                28
...
l.12 \startabblist
                  {
?

I haven't been able to figure out what's wrong or how to fix it.

I had just made changes to refactor the definitions of fonts. (I
confirmed that these changes really are a necessary cause of the error:
when I back out just these changes, the error goes away.)

>From the above error message I understand the error was detected during
the expansion of \startabblist. Here's the definition of abblist:

% Abbreviations
\definestartstop
  [abblist]
  [before={\setupbackgrounds[text][background=verticalline]
\starttextbackground[text]
\setuptab[headstyle={\switchtobodyfont[SansB,\SansBsize]},width=20mm,location=left]
\startcolumnset[abbcolumn] \startalignment[flushleft,nothyphenated]},
   after={\stopalignment \stopcolumnset \stoptextbackground
\setupbackgrounds[text][background=off]}]

>From that, one might guess that the font SansB or the font dimension
\SansBsize were the problem. But those definitions haven't changed
(though I would like to confirm that empirically with a run-time trace
message).

Here are the font settings changes that did occur:

E16fonts.tex:
changed this block:
  \definefont[SerifXLI][name:GentiumBookBasic-Italic at 10pt]
  \definefont[SerifXXL][name:GentiumBookBasic at 12pt]
  \definefont[SerifXXLB][name:GentiumBookBasic-Bold at 12pt]

to use size dimensions defined elsewhere:
\definefont[SerifXLI][name:GentiumBookBasic-Italic at \XLfontsize]
\definefont[SerifXXL][name:GentiumBookBasic at \XXLfontsize]
\definefont[SerifXXLB][name:GentiumBookBasic-Bold at \XXLfontsize]

E16settings.tex: I added these definitions:
\define\XLfontsize{14pt}
\define\XXLfontsize{16pt}

There are modes involved, so things are a bit more complicated, but I
believe that is the only effective difference.

I also created a log file, which I'll attach.
There is also a version with \tracingmacros=1, but it's 600K, so I'll
put it at
http://www.huttar.net/tmp/country-report-country_id-15-tracing.log

Thanks for taking a look. Please let me know what further information I
need to provide.
I can provide the .tex files themselves upon request.

I would especially like to know better techniques for debugging -- how I
can induce TeX/ConTeXt to tell me more about what's going on. I realize
that as a macro language, this is inherently difficult with TeX.

We are heavily invested in XeTeX, so switching to LuaTeX in the near
term is not an option.

ConTeXt version: ConTeXt  ver: 2012.05.30 11:26 MKII  fmt: 2012.11.14
int: english/english
(From TeX Live 2012)

XeTeX version: 3.1415926-2.4-0.9998 (TeX Live 2012) (format=cont-en
2012.11.14)

Lars