bug#19714: reftex under Xemacs 21.5.33 Mule

[David Kastrup]

Uwe Brauer <address@hidden> writes:

> Debugger entered--Lisp error: (invalid-regexp "Invalid regular expression")
>   
> re-search-forward("\\(?:\\\\label{\\(?1:[^}]*\\)}\\|\\[[^]]*\\<label[[:space:]]*=[[:space:]]*{?\\(?1:[^],}]+\\)}?\\)\\|\\(^\\)[
>   
> ]*\\\\\\(begin{SaveListing}\\|part\\|chapter\\|section\\|subsection\\|subsubsection\\|paragraph\\|subparagraph\\|addchap\\|addsec\\)\\*?\\(\\[[^]]*\\]\\)?[[{
>   \n\\]\\|\\(^\\)[    ]*\\\\\\(include\\|input\\|subfile\\)[{
>   ]+\\([^}    \n]+\\)\\|\\(^\\)[
>   
> ]*\\(\\\\appendix\\)\\|\\(\\\\glossary\\|\\\\index\\|\\\\nomenclature\\)[[{]"
>   nil t)

It would be my guess that

‘\(?NUM: … \)’
     is the "explicitly numbered group" construct.  Normal groups get
     their number implicitly, based on their position, which can be
     inconvenient.  This construct allows you to force a particular
     group number.  There is no particular restriction on the numbering,
     e.g., you can have several groups with the same number in which
     case the last one to match (i.e., the rightmost match) will win.
     Implicitly numbered groups always get the smallest integer larger
     than the one of any previous group.

is the culprit here.  At least in the current XEmacs manual
<URL:http://www.xemacs.org/Documentation/21.5/html/lispref_45.html#SEC599>
I can find nothing of the sort.

-- 
David Kastrup