context-filter (15sep11)

git-svn-id: svn://tug.org/texlive/trunk@23972 c570f23f-e606-0410-a88d-b1316a301751

2 files changed, 85 insertions, 9 deletions

diff --git a/Master/texmf-dist/doc/context/third/filter/filter.txt b/Master/texmf-dist/doc/context/third/filter/filter.txt
index 97dd922ea6f..ab4e9c6f90c 100644
--- a/Master/texmf-dist/doc/context/third/filter/filter.txt
+++ b/Master/texmf-dist/doc/context/third/filter/filter.txt
@@ -31,7 +31,7 @@ the blanks with the appropriate values. And so, the filter module was born.
 Compatibility
 ------------
 
-This module works with both MkII and MkIV
+This module works with both MkII and MkIV.
 
 Installation
 ------------
@@ -505,6 +505,79 @@ Then you can use
 
 to get a chess board.
 
+Dealing with expansion
+----------------------
+
+All the arguments of `filtercommand` must be fully expandable. Sometimes,
+writing an expandable command is tricky.  For example, suppose you want to use
+GNU barcode to draw barcodes. One way to do this is
+
+
+    \defineexternalfilter
+      [barcode]
+      [encoding=code128,
+       output=\externalfilterbasefile.eps,
+       continue=yes,
+       filtercommand=\barcodefiltercommand,
+       readcommand=\barcodereadcommand]
+
+    \def\barcodereadcommand#1%
+      {\externalfigure[#1]}
+
+    \def\barcodefiltercommand
+      {barcode -i \externalfilterinputfile\space -o \externalfilterbasefile.eps\space
+       -E % EPS output
+       -e \externalfilterparameter{encoding}
+
+One of the options that GNU barcode provides is
+
+       -n     ``Numeric'' output: don't print the ASCII form of the code, only
+               the bars.
+
+The ideal way to support this option is to provide a `label=(yes|no)` option,
+and in `\barcodefiltercommand` check the value of
+`\externalfilterparameter{label}`. If this value is `no`, add a `-n` flag. That
+is, redefine `\barcodefiltercommand` as follows:
+
+    \def\barcodefiltercommand
+      {barcode -i \externalfilterinputfile\space -o \externalfilterbasefile.eps\space
+       -E % EPS output
+       -e \externalfilterparameter{encoding}
+       \doif{\externalfilterparameter{label}}{no}{-n} }
+
+This approach does not work. The log says:
+
+    t-filter    > command : barcode -i barcode-temp-barcode-1.tmp -o barcode-temp-barcode-1.eps -E -e code128 \edef {yes}\edef yes{no}
+
+Instead of `-n`, we get `\edef {yes} \edef yes{no}` in the output. This is
+because `\doif` macro is not fully expandable. 
+
+One way to circumvent this limitation is to check for the value of `label`
+outside the `filtercommand`. The filter module provides a `filtersetup` option
+for this. For example, in  the above barcode example, use
+
+    \def\barcodelabeloption{}
+
+    \startsetups barcode:options
+      \doifelse{\externalfilterparameter{label}}{no}
+        {\edef\barcodelabeloption{-n}}
+        {\edef\barcodelabeloption{}}
+    \stopsetups
+
+    \defineexternalfilter
+        [barcode]
+        [....
+         filtersetups={barcode:options},
+         filtercommand=\barcodefiltercommand,
+         ...
+        ]
+
+    \def\barcodefiltercommand
+      {barcode -i \externalfilterinputfile\space -o \externalfilterbasefile.eps\space
+       -E % EPS output
+       -e \externalfilterparameter{encoding}
+       \barcodelabeloption % check for label
+      }
 
 Limitations
 ------------
@@ -601,4 +674,7 @@ Version History
     - Internal change: Defined own macros for setting attrbutes rather than
       using built-in ones.
 - **2011.09.03**
-    - Added `filtersetups` **TODO** document this feature
+    - Added `filtersetups` 
+- **2011.09.14**
+    - `\inline<filter>` now accepts optional arguments.
+    - `before=` and `after=` keys are disabled in `\inline<filter>`
diff --git a/Master/texmf-dist/tex/context/third/filter/t-filter.tex b/Master/texmf-dist/tex/context/third/filter/t-filter.tex
index babb9f43811..266c8e182ea 100644
--- a/Master/texmf-dist/tex/context/third/filter/t-filter.tex
+++ b/Master/texmf-dist/tex/context/third/filter/t-filter.tex
@@ -1,6 +1,6 @@
 %D \module
 %D   [     file=t-filter,
-%D      version=2011.09.03,
+%D      version=2011.09.14,
 %D        title=\CONTEXT\ User Module,
 %D     subtitle=Filter,
 %D       author=Aditya Mahajan,
@@ -9,7 +9,7 @@
 %D        email=adityam <at> ieee <dot> org,
 %D      license=Simplified BSD License]
 
-\writestatus{loading}{Filter (ver: 2011.09.03)}
+\writestatus{loading}{Filter (ver: 2011.09.14)}
 
 \ifx\undefined\normalexpanded \let\normalexpanded\expanded \fi
 
@@ -111,7 +111,7 @@
     \setvalue {\e!stop#1}{\externalfilter::process_filter}
 
     \setvalue{process#1file}{\dodoubleargument\externalfilter::process_file[#1]}
-    \setvalue{inline#1}{\externalfilter::inline[#1]}
+    \setvalue{inline#1}{\dodoubleargument\externalfilter::inline[#1]}
 
 \stoptexdefinition
 
@@ -155,11 +155,11 @@
     \endgroup
 \stoptexdefinition
    
-\starttexdefinition externalfilter::inline [#1]
+\starttexdefinition externalfilter::inline [#1][#2]
    \edef\externalfilter::name{#1}
 
    \begingroup % to keep assignments local
-   \setupexternalfilter[#1][\c!name=]
+   \setupexternalfilter[#1][\c!name=,\c!before=,\c!after=,#2]
 
    \externalfilter::set_filenames
 
@@ -362,7 +362,7 @@
                      \externalfilterparameter{\c!buffer\c!after}]
                     [\externalfilter::id]
          \startluacode
-           %% On Windows, os.rename does not overwrite files :(
+           %% -- On Windows, os.rename does not overwrite files :(
            file.copy("\jobname-\externalfilter::id.\f!temporaryextension", "\externalfilter::input_file")
          \stopluacode
      \stopmode
@@ -394,7 +394,7 @@
                {\doifmodeelse{force}
                    {\message{\externalfilterparameter\c!filtercommand}
                     \executesystemcommand
-                      {\externalfilterparameter\c!filtercommand}}
+                      {mtxrun --direct \externalfilterparameter\c!filtercommand}}
                    {\executesystemcommand
                     {mtxrun --ifchanged=\externalfilter::input_file\space 
                         --direct \externalfilterparameter\c!filtercommand}}}}}