diff options
| -rw-r--r-- | Master/texmf-dist/doc/context/third/filter/filter.txt | 80 | ||||
| -rw-r--r-- | Master/texmf-dist/tex/context/third/filter/t-filter.tex | 14 |
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}}}}} |