[XeTeX] polyglossia and ledpar conflict

[enrico.gregorio at univr.it]

Daron Wilson <daron.wilson at gmail.com> writes:

> I'm using the XeLaTeX on Mac OS X 10.6, with MacTeX 2009 
> installed. According to the TeXLive Utility that comes with 
> MacTeX 2009, all the packages installed are up to date
> 
> I've been working on typesetting a document with parallel texts, 
> having English on the left and Greek on the 
> right.    I started with the LateX packages 
> ledmac and ledpar because I would like to keep the English and 
> Greek synchronized, and I've managed to get a reasonably long 
> source document to compile satisfactorily, apart from a couple 
> of protruding lines due to lack of hyphenation support.  
> I'm fairly new to LaTeX, but after poking around a bit, it 
> seemed like the polyglossia package would help here.  On 
> adding polyglossia, the document would no longer compile, though 
> I've managed to narrow the problem down to an apparent conflict 
> between polyglossia and ledpar.
> 
> I've included a small document below that illustrates the 
> problem.  When I try to compile as written, I get the error 
> message shown at the bottom here. When I comment out the ledpar 
> package, everything compiles perfectly. In my editor, the line 
> number listed for the error is always the line containing the 
> actual Greek. (line 15 here)

The problem is that ledpar redefines \selectlanguage, which is ultimately used
by \begin{greek}, in a way that is incompatible with polyglossia.

You can patch it by replicating the definitions made by ledpar:

==== Change the two lines for ledmac and ledpar into this ====
\letcs\POLYselectlanguage{\string\selectlanguage}
\usepackage{ledmac}
\usepackage{ledpar}
\AtBeginDocument{
\renewcommand{\selectlanguage}[2][]{%
   \POLYselectlanguage[#1]{#2}%
   \ifledRcol
     \gdef\theledlanguageR{#2}%
   \else
     \gdef\theledlanguageL{#2}%
  \fi}
}
====

The strange \letcs is for accessing the internal name of \selectlanguage without incurring
in a loop; commands with an optional argument are bad beasts. :)

Give it a try, maybe something else will be necessary.

Ciao
Enrico

--
Enrico Gregorio          + Dipartimento di Informatica          + Tel: +39 045 8027937
Enrico.Gregorio at univr.it + Università degli Studi di Verona     +
(gregorio at math.unipd.it) + Strada le Grazie 15 / I-37134 Verona + Fax: +39 045 8027928