[Xy-pic] Latest XY Pic broken in Mac OS 10.6.7?

Ross Moore ross.moore at mq.edu.au
Mon Apr 18 00:27:02 CEST 2011

Hi Tom,

On 16/04/2011, at 9:18 AM, Tom Reinhardt wrote:

> Up until late this week (15 April 2011), I had been happily using XY Pic on a variety of machines: two Linux (Ubuntu 10.4) boxes, a Windoze Box (MiKTeX) at work, and my iMac, running 10.6.7, at home.

This sounds rather spurious to me, blaming a problem of the kind you
describe below on the OS version. 
If it were related to display and fonts, then yes, the OS may have 
a role. But certainly it should not during any TeX processing.

> Sometime about the middle of the week I noticed that TeXShop complained about formatting diagrams with "double arrows," such as the standard monomorphism, such as:
> \xymatrix{A\ar@<0.5ex>[r]^{f}\ar@<-0.5ex>[r]_{g} &B\ar[r]^{h} & C}
> Specifically, it complained about an extra "}" after the \next @ (it seemed to me that it was focussing on the arrow specification containing the second "@<loc>" specification.

No, I'd doubt that that is where it is happening.
More likely  \next@  has been split, due to the \catcode of @ being
not a letter, at some point.

My guess is that you have done some recent edits which result
in using an \Xy-pic diagram within a section title.

On the first run it works fine, but fails next time as the diagram
needs to be reproduced in the Table of Contents.
But too much expansion took place when the code for the title was
being written into the .aux file, and/or .toc file.

This is the most likely way for \next@  to appear within an incorrect

> Have you seen this before? Has anyone else noticed this problem this week?
> I confirmed that the code works fine on MiKTeX (Windoze) and on TeXLive (Linux); it's just on the Mac.

 ...and you wouldn't notice it on another platform unless you processed
the file multiple times.

> Naturally, I thank any kind soul for any advice/suggestions.

Please send the complete .log file of a run that fails, so it is possible
to get a better idea of where the problem occurs.

Also, have a look inside the .aux and .toc files, to see whether there
is evidence of "too much expansion" in either of these.
If so, then you will need to make use of \protect or "robust" commands,
to create the proper context for all the processing to run smoothly.

If you don't know what this means, then send a much greater chunk
of your job, including the LaTeX preamble and some of the overall
document structure, so that we can run tests.

> Regards,
> Tom R

Hope this helps,


Ross Moore                                       ross.moore at mq.edu.au 
Mathematics Department                           office: E7A-419      
Macquarie University                             tel: +61 (0)2 9850 8955
Sydney, Australia  2109                          fax: +61 (0)2 9850 8114

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