texexpand



TEXEXPAND(1)          User Contributed Perl Documentation         TEXEXPAND(1)




NAME

       texexpand - expand  \input and \include statements in a TeX file


DESCRIPTION

       General translation mechanism:

       The main program latex2html calls texexpand with the document name in
       order to expand some of its \input and \include statements, here also
       called ’merging’, and to write a list of sensitized style, class,
       input, or include file names.  When texexpand has finished, all is
       contained in one file, TMP_foo.  (assumed foo.tex is the name of the
       document to translate).

       In this version, texexpand cares for following environments that may
       span include files / section boundaries: a) \begin{comment} b)
       %begin{comment} c) \begin{any}  introduced with \excludecomment d)
       %begin{any} e) \begin{verbatim} f) \begin{latexonly} g)
       %begin{latexonly}

       e) - g) prevent texexpand from expanding input files, but the
       environment content goes fully into the output file.

       Together with each merging of \input etc. there are so-called
       %%%texexpand markers accompanying the boundary.

       When latex2html reads in the output file, it uses these markers to
       write each part to a separate file, and process them further.

       Detailed technical notes:

       1. %begin{latexonly} and %end{latexonly} have to be on a separate line.
       Anything between these tags (including the tags) is discarded.

       2. \begin{latexonly} and \end{latexonly} have to be on a separate line.
       Anything between these tags (including the tags) is not expanded.

       3. [%\]begin{"to exclude"} and [%\]end{"to exclude"} have to be on a
       separate line.  Anything between these tags (including the tags) is
       discarded.

       4. \begin{verbatim/verbatim*} and \end{verbatim/verbatim*} have to be
       on a separate line.  Anything between these tags (including the tags)
       is not expanded.

       5. The scope of any such tags may extend over several files.  The
       opening tag for latexonly may occur on a different include level than
       the closing tag.  The opening tag for verbatim/"to exclude" must occur
       within the same file than the closing tag.

       6. Warnings are printed when the document has been parsed and open tags
       remain.

       7. When in a "to exclude"/verbatim environment, texexpand won’t
       recognize ANY command except the corresponding closing tag.  There
       cannot be any nested constructions.  This behaviour is identical to
       that of LaTeX.

       8. \begin{latexonly},\end{latexonly} may be nested, whereas
       %begin{latexonly},%end{latexonly} may not be nested.

       9. A "%" tag cannot close a "\" tag, and vice versa.

       10. Every \document(class│style), \usepackage, \input and \include
       command has to be on a separate line.

       11. Everything behind a ‘%’ that isn’t preceded by a ‘\’ is regarded as
       a comment, i.e. it is printed but not interpreted.

       12. If any command listed in 10. is preceded by an occurence of ‘\verb’
       or ‘\latex’ then it is NOT interpreted. This crashes on lines like
       this: blah blah \verb+foo foo+ \input{bar} % bar won’t be loaded!

       13. Packages provided via \usepackage are handled the same way as
       ‘options’ in \document(class│style), i.e. they are included when
       -auto_exclude is off, the package isn’t in @dont_include *OR* the
       package is in @do_include (new). They are added to the style file
       together with their options if the file itself hasn’t been merged.
       \documentclass[options]{class} searches for every option.clo,
       \documentstyle[options]{style} searches for every option.sty.
       \usepackage[options]{packages} searches for every package.sty.

       14. Each texinputs directory is searched for input files/styles. If it
       ends in ‘//’, the whole subdirectory tree is searched.

       15. \input / \include merge the given file (if found under the given
       name or with .tex extension) if its basename is in @do_include or if it
       isn’t in @dont_include or if the given filename doesn’t end in
       .sty/.clo/.cls when -auto_exclude is set.

       Notes

       Recognizes \documentclass, \documentstyle, \usepackage,
       \RequirePackage, \begin{verbatim}...\end{verbatim},
       %begin{latexonly}...%end{latexonly},
       \begin{latexonly}...\end{latexonly}, \input, \include, \verb, \latex
       \endinput, \end{document} \includecomment, \excludecomment \begin{"to
       exclude"}, \end{"to exclude"} %begin{"to exclude"}, %end{"to exclude"}


The gory Details

       Include and parse a file.  This routine is recursive, see also
       &process_input_include_file, &process_document_header, and
       &process_package_cmd.

       Two global flags control the states of texexpand.
        o $active is true if we should interprete the lines to expand files,
       check for packages, etc.
        o $mute is true if we should prevent the lines from going into the out
       file.

       We have three general states of texexpand:
        1) interprete the lines and pass them to the out file This is the
       normal case. Corresponding: $active true, $mute false

        2) interprete minimal and suppress them
       This is when parsing inside a comment environment, which
       also would retain its body from LaTeX. => $active false, $mute true

        3) interprete minimal and pass the lines to the out file
       This is inside a verbatim or latexonly environment.
       The line of course must be at least interpreted to determine the closing tag.
       => $active false, $mute false

       Any environment may extend over several include files.  Any
       environement except verbatim and latexonly may have its opening or
       closing tag on different input levels.  The comment and verbatim
       environments cannot be nested, as is with LaTeX.  We must at least
       parse verbatim/comment environments in latexonly environments, to catch
       fake latexonly tags.

       The work scheme: Five functions influence texexpand’s behavior.  o
       &process_file opens the given file and parses the non-comment part in
       order to set $active and $mute (see above).  It calls &interprete to
       interprete the non-comment content and either continues with the next
       line of its file or terminates if &interprete detected the
       \end{document} or an \endinput.

       o &interprete handles some LaTeX tags with respect to the three states
       controlled by $active and $mute.  Regarding to \input│include,
       \document(class│style), and \(use│Require)package the functions
       &process_input_include_file, &process_document_header, and
       &process_package_cmd are called respectively.

       o These three functions check if the file name or option files are
       enabled or disabled for merging (via TEXE_DO_INCLUDE or
       TEXE_DONT_INCLUDE).  Any file that is to include will be ’merged’ into
       the current file, i.e.  the function &process_file is called at this
       place in time (recursively).  This will stop interpretation at the
       current line in file, start with the new file to process and continues
       with the next line as soon as the new file is interpreted to its end.

       The call tree (noweb+xy.sty would be handy here):

           main
             │
             v
        +->process_file
        │    │
        │    v
        │  interprete (with respect to the current line, one of that three)
        │    │                           │                        │
        │    v                           v                        v
        │  process_input_include_file  process_document_header  process_package_cmd
        │    │                           │                        │
        │    v                           v                        v
        +----+---------------------------+------------------------+

       Bugs: o Since the latexonly environment is not parsed, its contents
       might introduce environments which are not recognized.

       o The closing tag for latexonly is not found if hidden inside an input
       file.

       o One environment tag per line, yet!

       o If I would have to design test cases for this beast I would
       immediately desintegrate into a logic cloud.

       Notes:

       o Ok, I designed test cases for it.  Please refer to test ’expand’ of
       the regression test suite in the developers’ module of the l2h
       repository.

       o -unsegment feature: In this (rare) case, the user wants to translate
       a segmented document not in segments but in a whole (for testing, say).
       We enable this by recognizing the \segment command in &interprete,
       causing the segment file to be treated like \input but loosing the
       first lines prior to \startdocument (incl.), as controlled via
       $segmentfile.  On how to segment a document you are best guided by
       section ‘‘Document Segmentation’’ of the LaTeX2HTML manual.


CAVEATS

       This utility is automatically configured and built to work on the local
       setup. If this setup changes (e.g. some of the external commands are
       moved), the script has be be reconfigured.


Authors

        Based on texexpand by Robert Thau, MIT AI lab, including modifications by
        Franz Vojik <vojik@de.tu-muenchen.informatik>
        Nikos Drakos <nikos@cbl.leeds.ac.uk>
        Sebastian Rahtz <spqr@uk.ac.tex.ftp>
        Maximilian Ott <max@com.nec.nj.ccrl>
        Martin Boyer
        Herbert Swan
        Jens Lippmann













3rd Berkeley Distribution    perl 5.005, patch 03                 TEXEXPAND(1)

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