merge from xcite branch

base/doc/ltnews30.tex

@@ -362,6 +362,21 @@ \subsection{\pkg{varioref}: }
 
 
 
+\subsection{\pkg{xr}: Support citations to bibiographies in external documents}
+
+The \pkg{xr} package can be used to reference labels in external
+document, e.g., when a work is split over different documents that
+need to be processed separateley, but has \cs{ref} or \cs{pageref}
+links between each other. With this update \cs{cite} commands and
+their cousins can now also reference bibliographies in external
+documents, a feature that was originally made available by the package
+\pkg{xcite} by Enrico Gregorio.
+
+Note that for technical reasons \pkg{xr} doesn't work with
+\pkg{hyperref}. Use \pkg{xr-hyper} instead if you need the latter
+package.
+
+
 \section{Changes to packages in the \pkg{amsmath} category}
 
 \subsection{\pkg{amsmath}: Introduce \texttt{overunderset} command}

required/tools/xr.dtx

@@ -21,11 +21,11 @@
 %
 % \fi
 % \iffalse
-%% File: xr.dtx Copyright (C) 1994-1994 2018 2019 David Carlisle
+%% File: xr.dtx Copyright (C) 1993-2019 David Carlisle
 %
 %<package>\NeedsTeXFormat{LaTeX2e}
 %<package>\ProvidesPackage{xr}
-%<package>         [2019/01/05 v5.04 eXternal References (DPC)]
+%<package>         [2019/07/22 v5.05 eXternal References (DPC)]
 %
 %<*driver>
 \documentclass{ltxdoc}
@@ -56,7 +56,8 @@
 %           aux files of \cmd\include'ed files. (Reported by J-PD)}
 %
 % \changes{v5.02}{1994/05/28}{Update for LaTeX2e}
-% \changes{v5.02}{1994/05/28}{Fix for conditionals in aux file}
+% \changes{v5.03}{2018/10/01}{Fix for conditionals in aux file}
+% \changes{v5.05}{2019/07/20}{include xcite}
 %
 %
 % This package implements a system for eXternal References.
@@ -83,6 +84,11 @@
 % characters can not usually be used in |\label|, and similarly may not
 % be used in the optional argument to |\externaldocument|.
 %
+% As first suggested in Enrico Gregorio's |xcite| package, the current version
+% also allows |\cite| to reference |\bibitem| in the external document.
+% For fcompatibility with |xcite|, |\externalcitedocument| is made available 
+% as an alias for |\externaldocument|
+%
 % \StopEventually{}
 %
 % \section{The macros}
@@ -94,6 +100,7 @@
 % Check for the optional argument.
 %    \begin{macrocode}
 \def\externaldocument{\@ifnextchar[\XR@{\XR@[]}}
+\let\externalcitedocument\externaldocument
 %    \end{macrocode}
 %
 % Save the optional prefix. Start processing the first |aux| file.
@@ -159,11 +166,13 @@
 \long\def\XR@test#1#2#3#4\XR@{%
   \let\XR@tempa\@gobbletwo
   \ifx#1\newlabel
-    \let\XR@tempa\@firstoftwo%
+    \let\XR@tempa\@firstoftwo
+  \else\ifx#1\bibcite
+    \let\XR@tempa\@firstoftwo
   \else\ifx#1\@input
      \let\XR@tempa\@secondoftwo
-  \fi\fi
-   \XR@tempa{\newlabel{\XR@prefix#2}{#3}}{\edef\XR@list{\XR@list#2\relax}}%
+  \fi\fi\fi
+   \XR@tempa{#1{\XR@prefix#2}{#3}}{\edef\XR@list{\XR@list#2\relax}}%
   \ifeof\@inputcheck\expandafter\XR@aux
   \else\expandafter\XR@read\fi}
 %    \end{macrocode}