[XeTeX] xmaths: bugs report

[Bruno Voisin]

Result from a half-hour encounter with xmaths.sty this morning:

- Characters produced through \mathbin or \mathord in stix-tex- 
plane0.tex must be enclosed in braces when used as single-character  
subscripts or superscripts. I saw this with \star, \pm and \infty: _ 
\star must be replaced by _{\star} and ^\infty by ^{\infty}, for  
example. Typical error messages:

> ! Missing { inserted.
> <to be read again>
>                    \mathbin
> l.324 ... the area of the obstacle, $\rho_0A_\star
>                                                   $ its added mass  
> (per unit...

> ! Missing { inserted.
> <to be read again>
>                    \mathord
> l.803 .../U}^{N/U}\mathrm{d}k\int_{-\infty}^\infty
>                                                   \mathrm{d}l\,

On the other hand, characters produced through \mathalpha in stix-tex- 
plane0.tex can be used as single-character subscripts or superscripts  
with no problem. For example, F_\ell, J_\nu or \int_\delta work  
allright.

- \{ and \} seem not to be recognized as delimiters any more, so that  
\left\{ produces an error message about a missing delimiter. What's  
confusing is that the error message appears a couple of lines after  
the \{, so that the origin for it is a bit difficult to trace.  
Typical error message:

> ! Missing delimiter (. inserted).
> <to be read again>
>                    \mathopen
> l.1306 ...t-t')\frac{|Z(t')|}{R(t')}\right]^{1/2}}

whereas the complete equation was:

>   \frac{\displaystyle
>         \exp\left\{-\mathrm{i}\left[N(t-t')\frac{|Z(t')|}{R(t')}
>         -\frac{\pi}{4}\right]\right\}}
>        {\displaystyle
>         \left[N(t-t')\frac{|Z(t')|}{R(t')}\right]^{1/2}}

so that the \left\{ and \right\} triggering the bug appeared 2 and 3  
lines earlier. The bug seems to happen with all delimiters that are  
entered as control sequences, so that replacing, for example, \{ by  
\lbrace and \} by \rbrace doesn't work any better.

- Primes produced through either ' or ^{\prime} are replaced by empty  
boxes in the output, such as:

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This appears in a document loading first Lucida then Hoefler Text,  
through:

\usepackage[LY1]{fontenc}
\usepackage[expert,lucidasmallscale,vargreek,altbullet]{lucidabr}
\usepackage{xunicode}
\usepackage{fontspec}
\usepackage{xmaths}
\defaultfontfeatures{%
   Mapping=tex-text,
   Numbers=Lining,
   Contextuals={NoLineInitial,NoLineFinal}
   }
\setromanfont{Hoefler Text}

so that I'm not sure where the \prime is supposed to come from  
(Lucida or Hoefler).

Happy debugging!

Bruno