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diff --git a/Master/texmf-dist/tex/context/third/filter/t-filter.tex b/Master/texmf-dist/tex/context/third/filter/t-filter.tex
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+%D \module
+%D   [     file=t-filter,
+%D      version=2010.09.26,
+%D        title=\CONTEXT\ User Module,
+%D     subtitle=Filter,
+%D       author=Aditya Mahajan,
+%D         date=\currentdate,
+%D    copyright=Aditya Mahajan,
+%D        email=adityam <at> umich <dot> edu,
+%D      license=Simplified BSD License]
+
+\writestatus{loading}{ConTeXt User Module / Filter}
+
+\startmodule    [filter]
+
+\unprotect
+
+\startinterface all
+  \setinterfaceconstant {filter}           {filter}
+  \setinterfaceconstant {filtercommand}    {filtercommand}
+  \setinterfaceconstant {output}           {output} 
+  \setinterfaceconstant {read}             {read} 
+  \setinterfaceconstant {readcommand}      {readcommand} 
+\stopinterface
+
+\def\??externalfilter??{externalfilter}
+\def\currentexternalfilter{}
+\def\externalfiltercountername{\??externalfilter??-\currentexternalfilter-counter}
+
+\def\externalfilterparameter#1%
+  {\csname
+     \docheckparentparameter{\??externalfilter??\currentexternalfilter}{#1}%
+   \endcsname}
+
+\def\docheckparentparameter#1#2%
+  {\ifcsname#1#2\endcsname
+      #1#2%
+    \else
+      \expandafter\redocheckparentparameter\csname#1\s!parent\endcsname{#2}%
+    \fi}
+
+\def\redocheckparentparameter#1#2%
+  {\ifx#1\relax
+      \s!empty
+   \else
+      \docheckparentparameter{#1}{#2}%
+   \fi}
+
+\def\setupexternalfilters
+  {\dodoubleargument\dosetupexternalfilters}
+  
+\def\dosetupexternalfilters[#1][#2]%
+  {\ifsecondargument
+     \getparameters[\??externalfilter??#1][#2]%
+   \else
+     \getparameters[\??externalfilter??][#1]%
+   \fi}
+
+
+\def\defineexternalfilter
+  {\dodoubleargument\dodefineexternalfilter}
+
+\def\dodefineexternalfilter[#1][#2]%
+  {\edef\currentexternalfilter{#1}%
+  \getparameters[\??externalfilter??#1][\s!parent=\??externalfilter??,#2]%
+   \doif{\externalfilterparameter\c!continue}\v!yes
+      {\expandafter\newcounter\csname\externalfiltercountername\endcsname}%
+   \setvalue{\e!start#1}{\bgroup\obeylines\dodoubleargument\dostartexternalfilter[#1]}%
+   \setvalue{\e!stop#1}{\doprocessexternalfilter}%
+   \setvalue{process#1file}{\dodoubleargument\doprocessexternalfile[#1]}%
+   %TODO: Inline.
+   %\setvalue{#1}##1{\save ##1 to file}
+   }
+
+
+\def\dostartexternalfilter[#1][#2]% filter options
+  {% Initializations
+   \egroup %\bgroup in \start#1
+   \begingroup % to keep assignments local
+   \edef\currentexternalfilter   {#1}%
+   \getparameters[\??externalfilter??#1][\c!name=,#2]%
+   % Set the name of temp file for os filter
+   \doifelse{\externalfilterparameter\c!continue}\v!yes
+       {\edef\externalfiltertmpfile{\??externalfilter??-#1-\csname\externalfiltercountername\endcsname}}
+       {\edef\externalfiltertmpfile{\??externalfilter??-#1}}
+   \doifsomething{\externalfilterparameter\c!name}
+       {\edef\externalfiltertmpfile{\externalfilterparameter\c!name}}
+   % The following  macros are useful for filter= and filtercommand= options
+   % The basename of the external file 
+   \edef\externalfilterbasefile  {\jobname-\externalfiltertmpfile}%
+   % The name of the buffer to which data is written
+   \edef\externalfilterinputfile {\externalfilterbasefile.tmp}%
+   % The name of the file to which the output is written
+   \edef\externalfilteroutputfile{\externalfilterparameter\c!output}%
+   % Capture the contents of the buffer
+   \dostartbuffer[\externalfiltertmpfile][\e!start#1][\e!stop#1]}
+
+\def\doprocessexternalfilter%
+  {% By defualt, buffers are in memory in MkIV
+   \doifmode\s!mkiv{\savebuffer[\externalfiltertmpfile]}%
+   % Run external command
+   \doexecuteexternalfilter
+   \doreadprocessedfile
+   \endgroup 
+   % Finalization
+   \doif{\externalfilterparameter\c!continue}\v!yes
+        {\expandafter\increment\csname\externalfiltercountername\endcsname}%
+   }
+
+\def\doexecuteexternalfilter
+  {\doifelse{\externalfilterparameter\c!continue}\v!yes
+   {\doifmode{*first}
+     {\executesystemcommand
+      {mtxrun --ifchanged=\externalfilterinputfile\space 
+          bin:\externalfilterparameter\c!filtercommand}}}
+   {\executesystemcommand
+      {\externalfilterparameter\c!filtercommand}}}
+
+\def\doreadprocessedfile
+  {\doif{\externalfilterparameter\c!read}\v!yes
+      {\doiffileelse{\externalfilteroutputfile}
+          {\dodoreadprocessedfile}
+          {{\tttf TODO: File \externalfilteroutputfile\ not found! Check your definition}}}}
+
+\def\dodoreadprocessedfile
+  {\begingroup
+   \externalfilterparameter\c!before
+   \processcommacommand[\externalfilterparameter\c!setups]\directsetup
+   \externalfilterparameter\c!readcommand\externalfilteroutputfile
+   \externalfilterparameter\c!after
+   \endgroup}
+
+\def\doprocessexternalfile[#1][#2]%
+  {\edef\currentexternalfilter    {#1}%
+   \edef\externalfilterinputfile  {#2}%
+   \splitfiletype {#2}%
+   %BEWARE. \edef doesn not work
+   \def\externalfilterbasefile   {\splitoffname}
+   \def\externalfilteroutputfile{\externalfilterparameter\c!output}%
+   \doexecuteexternalfilter
+   \doreadprocessedfile}
+   
+
+\setupexternalfilters
+  [
+   \c!before=,
+   \c!after=,
+   \c!setups=,
+   \c!continue=\v!no,
+   \c!read=\v!yes,
+   \c!readcommand=\ReadFile,
+   \c!output=\externalfilterbasefile.tex,
+   \c!filter=,
+   \c!filtercommand={\externalfilterparameter\c!filter\space \externalfilterinputfile},
+ ]
+   
+% For tracing
+\def\showexternalfilterstate
+  {\starttable[|l|l|]
+  \NC currentexternalfilter     \NC \currentexternalfilter      \NC \AR
+  \NC externalfilterinputfile   \NC \externalfilterinputfile    \NC \AR
+  \NC externalfilteroutputfile  \NC \externalfilteroutputfile   \NC \AR
+  \NC externalfilterbasefile    \NC \externalfilterbasefile     \NC \AR
+  \stoptable}
+   
+\protect
+\stopmodule