NAME

LaTeX::Driver - Latex driver

VERSION

This document describes version 0.08 of LaTeX::Driver.

SYNOPSIS

    use LaTeX::Driver;

    $drv = LaTeX::Driver->new( source  => \$doc_text,
                               output  => $filename,
                               format  => 'pdf',
                               %other_params );
    $ok    = $drv->run;
    $stats = $drv->stats;
    $drv->cleanup($what);

DESCRIPTION

The LaTeX::Driver module encapsulates the details of invoking the Latex programs to format a LaTeX document. Formatting with LaTeX is complicated; there are potentially many programs to run and the output of those programs must be monitored to determine whether further processing is required.

This module runs the required commands in the directory specified, either explicitly with the dirname option or implicitly by the directory part of basename, or in the current directory. As a result of the processing up to a dozen or more intermediate files are created. These can be removed with the cleanup method.

SUBROUTINES/METHODS

new(%params)

This is the constructor method. It creates a driver object on which the run method is used to format the document specified. The main arguments are source and output; the source argument is required to specify the input document; output is only mandatory if source is a scalar reference.

The full list of arguments is as follows:

source: This parameter is mandatory; it can either specify the name of the document to be formatted or be a reference to a scalar containing the document source.
output: specifies the output for the formatted document; this may either be a file name or be a scalar reference. In the latter case the contents of the formatted document file is copied into the scalar variable referenced.
format: the format of output required: one of "dvi" (TeX Device Independent format), "ps" (PostScript) or "pdf" (Adobe Portable Document Format). The follow special values are also accepted: "pdf(ps)" (generates PDF via PostScript, using dvips and ps2pdf), "pdf(dvi)" (generates PDF via dvi, using dvipdfm). If not specified then the format is determined from the name of the output document if specified, or defaults to PDF.
tmpdir: Specifies whether the formatting should be done in a temporary directory in which case the source document is copied into the directory before formatting. This option can either take the value 1, in which case a temporary directory is automatically generated, or it is taken as the name of a subdirectory of the system temporary directory. A temporary directory is always created if the source document is specified as a scalar reference.
paths: Specifies a mapping of program names to full pathname as a hash reference. These paths override the paths determined at installation time.
maxruns: The maximum number of runs of the formatter program (defaults to 10).
extraruns: The number of additional runs of the formatter program after the document has stabilized.
cleanup: Specifies whether temporary files and directories should be automatically removed when the object destructor is called. Accepted values are none (do no cleanup), logfiles (remove log files) and tempfiles (remove log and temporary files). By default the destructor will remove the entire contents of any automatically generated temporary directory, but will leave all other files intact.
indexstyle: The name of a makeindex index style file that should be passed to makeindex.
indexoptions: Specifies additional options that should be passed to makeindex. Useful options are: -c to compress intermediate blanks in index keys, -l to specify letter ordering rather than word ordering, -r to disable implicit range formation. Refer to makeindex(1) for full details.
texinputs: Specifies one or more directories to be searched for LaTeX files.
DEBUG: Enables debug statements if set to a non-zero value.
DEBUGPREFIX: Sets the debug prefix, which is prepended to debug output if debug statements. By default there is no prefix.

The constructor performs sanity checking on the options and will die if the following conditions are detected:

no source is specified
an invalid format is specified

The constructor method returns a driver object.

run()

Format the document.

stats()

Returns a reference to a hash containing stats about the processing tht was performed, containing the following items:

pages: number of pages in the formatted document
bytes: number of bytes in the formatted document
runs: hash of the number of times each of the programs was run

Note: the return value will probably become an object in a future version of the module.

cleanup($what)

Removes temporary intermediate files from the document directory and resets the stats.

Not yet implemented

program_path($program_name, $opt_value)

Get or set the path to the named program. Can be used as a class method to set the default path or as an object method to set the path for that instance of the driver object.

There are a number of other methods that are used internally by the driver. Calling these methods directly may lead to unpredictable results.

run_latex: Runs the formatter (latex or pdflatex).
need_to_run_latex: Determines whether the formatter needs to be run.
reset_latex_required: Reset the flags that indicate whether latex needs to be re-run (invoked prior to each iteration of running any necessary commands).
run_bibtex: Runs bibtex to generate the bibliography.
need_to_run_bibtex: Determines whether bibtex needs to be run.
run_makeindex: Runs makeindex to generate the index.
need_to_run_makeindex: Determines whether makeindex needs to be run.
run_dvips: Runs dvips to generate postscript output from an intermediate .dvi file.
run_ps2pdf: Runs ps2pdf to generate PDF output from an intermediate PostScript file.
run_pdf2ps: Runs pdf2ps to generate PostScript output from an intermediate PDF file.
run_command: Run a command in a controlled environment, allowing for operating system differences.
copy_to_output: Copy the output to its final destination.
throw: Throw an exception.
debug: Print a debug message - the caller should test $DEBUG to determine whether to invoke this function.

DIAGNOSTICS

The following errors may be detected by the constructor method.

not available on XXX: The module is not supported on MacOS, OS/2 or VMS (or on a host of other operating systems but these are the only ones that are explicitly tested for).
no source specified: The source paramater should be specified as the name of a LaTeX source file or it should be a reference to a scalar variable holding the LaTeX source document.
source is an invalid reference: source is a reference, but not a reference to a scalar variable
source file XXX.tex does not exist: The source file specified does not exist
output directory DIR does not exist: An output parameter was specified as a scalar value, which was taken as the name of the output file, but the directory part of the path does not exist.
invalid output format XXX: An output format was specified, either explicitly or implicitly as the extension of the output file, but the output format specified is not supported.
cannot create temporary directory: The module could not create the temporary directory, which is used if the source is not specified as a filename, and the output is not to be left in the same directory as the source, or if a temporary directory name is specified explicitly.
cannot create temporary latex file: The module has determined that it needs to create a temporary file containing the source document but it cannot.
cannot copy XXX.ext to temporary directory: The module was trying to copy the specified source file to the temporary directory but couldn't. Perhaps you specified the temporary directory name explicitly but the directory does not exist or is not writeable.

The following errors may be detected when the driver's run() method is called:

file XXX.tex does not exist: The source file does not exist; it may have been removed between the time the constructor was called and the time that the driver was run.
PROGRAM exited with errors: ERRORS: The named program (latex or pdflatex) exited with the errors listed. You may have errors in your source file.
bibtex FILE failed (EXITCODE): The bibtex program exited with errors. These are not fully parsed yet.
failed to open BASEPATH.cit: The driver generates its own temporary file listing the citations for a document, so that it can determine whether the citations have changed. This error indicates that it was unable to create the file.
makeindex FILE failed (EXITCODE): The makeindex program exited with errors. These are not fully parsed yet.
dvips FILE failed (EXITCODE): The dvips program exited with errors. These are not fully parsed yet.
ps2pdf FILE failed (EXITCODE): The ps2pdf program exited with errors. These are not fully parsed yet.
PROGNAME cannot be found, please specify its location: The pathname for the specified program was not found in the modules configuration. The program may not have been found and the pathname not been explicitly specified when the module was installed.
failed to copy FILE to OUTPUT: The driver failed to copy the formatted file to the specified output location.

CONFIGURATION AND ENVIRONMENT

DEPENDENCIES

LaTeX::Driver depends on latex and friends being installed.

BUGS AND LIMITATIONS

This is beta software - there are bound to be bugs and misfeatures. If you have any comments about this software I would be very grateful to hear them; email me at <a.ford@ford-mason.co.uk>.

Among the things I am aware of are:

I haven't worked out how I am going to deal with tex-related environment variables.

FUTURE DIRECTIONS

Look at how path variables could be specified to the filter (TEXINPUTS, TEXINPUTS_latex, TEXINPUTS_pdflatex, BIBINPUTS, etc), and how these should interact with the system paths.
Investigate pre- and post-processors and other auxilliary programs.

BACKGROUND

This module has its origins in the original latex filter that was part of Template Toolkit prior to version 2.16. That code was fairly simplistic; it created a temporary directory, copied the source text to a file in that directory, and ran either latex or pdflatex on the file once; if postscript output was requested then it would run dvips after running latex. This did not cope with documents that contained forward references, a table of contents, lists of figures or tables, bibliographies, or indexes.

The current module does not create a temporary directory for formatting the document; it is given the name and location of an existing LaTeX document and runs the latex programs in the directory specified (the Template Toolkit plugin will be modified to set up a temporary directory, copy the source text in, then run this module, extract the output and remove the temporary directory).

INTERNALS

This section is aimed at a technical audience. It documents the internal methods and subroutines as a reference for the module's developers, maintainers and anyone interesting in understanding how it works. You don't need to know anything about them to use the module and can safely skip this section.

Formatting with LaTeX or PDFLaTeX

LaTeX documents can be formatted with latex or pdflatex; the former generates a .dvi file (device independent - TeX's native output format), which can be converted to PostScript or PDF; the latter program generates PDF directly.

finds inputs in TEXINPUTS, TEXINPUTS_latex, TEXINPUTS_pdflatex, etc

Generating indexes

The standard program for generating indexes is makeindex, is a general purpose hierarchical index generator. makeindex accepts one or more input files (.idx), sorts the entries, and produces an output (.ind) file which can be formatted.

The style of the generated index is specified by a style file (.ist), which is found in the path specified by the INDEXSTYLE environment variable.

An alternative to makeindex is xindy, but that program is not widespread yet.

Generating bibliographies with BiBTeX

BiBTeX generates a bibliography for a LaTeX document. It reads the top-level auxiliary file (.aux) output during the running of latex and creates a bibliograpy file (.bbl) that will be incorporated into the document on subsequent runs of latex. It looks up the entries specified by \cite and \nocite commands in the bibliographic database files (.bib) specified by the \bibliography commands. The entries are formatted according to instructions in a bibliography style file (.bst), specified by the \bibliographystyle command.

Bibliography style files are searched for in the path specified by the BSTINPUTS environment variable; for bibliography files it uses the BIBINPUTS environment variable. System defaults are used if these environment variables are not set.

Running Dvips

The dvips program takes a DVI file produced by TeX and converts it to PostScript.

Running ps2pdf

The ps2pdf program invokes Ghostscript to converts a PostScript file to PDF.

Running on Windows

Commands are executed with cmd.exe. The syntax is:

   cmd /c "cd $dir && $program $args"

This changes to the specified directory and executes the program there, without affecting the working directory of the the Perl process.

Need more information on how to set environment variables for the invoked programs.

Miscellaneous Information

This is a placeholder for information not yet incorporated into the rest of the document.

May want to mention the kpathsea library, the kpsewhich program, the web2c TeX distribution, TeX live, tetex, TeX on Windows, etc.

AUTHOR

Andrew Ford <a.ford@ford-mason.co.uk>

LICENSE AND COPYRIGHT

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

CPAN RT