LaTeX::Encode - encode characters for LaTeX formatting


LaTeX-Encode documentation Contained in the LaTeX-Encode distribution.

Index


Code Index:

NAME

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LaTeX::Encode - encode characters for LaTeX formatting

SYNOPSIS

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  use LaTeX::Encode;

  $latex = latex_encode($text, %options);

VERSION

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This manual page describes version 0.03 of the LaTeX::Encode module.

DESCRIPTION

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This module provides a function to encode text that is to be formatted with LaTeX. It encodes characters that are special to LaTeX or that are represented in LaTeX by LaTeX commands.

The special characters are: \ (command character), { (open group), } (end group), & (table column separator), # (parameter specifier), % (comment character), _ (subscript), ^ (superscript), ~ (non-breakable space), $ (mathematics mode).

Note that some of the LaTeX commands for characters are defined in the LaTeX textcomp package. If your text includes such characters, you will need to include the following lines in the preamble to your LaTeX document.

    \usepackage[T1]{fontenc}
    \usepackage{textcomp}

The function is useful for encoding data that is interpolated into LaTeX document templates, say with Template::Plugin::Latex (shameless plug!).

SUBROUTINES/METHODS

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latex_encode($text, %options)

Encodes the specified text such that it is suitable for processing with LaTeX. The behaviour of the filter is modified by the options:

except

Lists the characters that should be excluded from encoding. By default no special characters are excluded, but it may be useful to specify except = "\\{}" to allow the input string to contain LaTeX commands such as "this is \\textbf{bold} text" (the doubled backslashes in the strings represent Perl escapes, and will be evaluated to single backslashes).

iquotes

If true then single or double quotes around words will be changed to LaTeX single or double quotes; double quotes around a phrase will be converted to "``" and "''" and single quotes to "`" and "'". This is sometimes called "intelligent quotes"

use_textcomp

By default the latex_encode filter will encode characters with the encodings provided by the textcomp LaTeX package (for example the Pounds Sterling symbol is encoded as \\textsterling{}). Setting use_textcomp = 0 turns off these encodings. NOT YET IMPLEMENTED

EXAMPLES

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The following snippet shows how data from a database can be encoded and inserted into a LaTeX table, the source of which is generated with LaTeX::Table.

    my $sth = $dbh->prepare('select col1, col2, col3 from table where $expr');
    $sth->execute;
    while (my $href = $sth->fetchrow_hashref) {
        my @row;
        foreach my $col (qw(col1 col2 col3)) {
            push(@row, latex_encode($href->{$col}));
        }
        push @data, \@row;
    }

    my $headings = [ [ 'Col1', 'Col2', 'Col3' ] ];

    my $table = LaTeX::Table->new( { caption => 'My caption',
                                     label   => 'table:caption',
                                     type    => 'xtab',
                                     header  => $header,
                                     data    => \@data } );

    my $table_text = $table->generate_string;    

Now $table_text can be interpolated into a LaTeX document template.

DIAGNOSTICS

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None. You could probably break the latex_encode function by passing it an array reference as the options, but there are no checks for that.

CONFIGURATION AND ENVIRONMENT

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Not applicable.

DEPENDENCIES

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The HTML::Entities and Pod::LaTeX modules were used for building the encoding table in LaTeX::Encode::EncodingTable, but this is not rebuilt at installation time. The LaTeX::Driver module is used for formatting the character encodings reference document.

INCOMPATIBILITIES

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None known.

BUGS AND LIMITATIONS

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Not all LaTeX special characters are included in the encoding tables (more may be added when I track down the definitions).

The use_textcomp option is not implemented.

AUTHOR

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

LICENSE AND COPYRIGHT

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SEE ALSO

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Template::Plugin::Latex


LaTeX-Encode documentation Contained in the LaTeX-Encode distribution.

#========================================================================
#
# LaTeX::Encode
#
# DESCRIPTION
#   Provides a function to encode text that contains characters
#   special to LaTeX.
#
# AUTHOR
#   Andrew Ford <a.ford@ford-mason.co.uk>
#
# COPYRIGHT
#   Copyright (C) 2007 Andrew Ford.   All Rights Reserved.
#
#   This module is free software; you can redistribute it and/or
#   modify it under the same terms as Perl itself.
#
#   $Id: Encode.pm 10 2007-10-03 11:00:21Z andrew $
#========================================================================

package LaTeX::Encode;

use strict;
use warnings;

use Exporter;
use base qw(Exporter);
use LaTeX::Encode::EncodingTable;

our $VERSION = 0.03;
our @EXPORT  = qw(latex_encode);


# Encode text with characters special to LaTeX

sub latex_encode {
    my $text = shift;
    my $options = ref $_[0] ? shift : { @_ };
    my $exceptions   = $options->{except};
    my $iquotes      = $options->{iquotes};
    my $use_textcomp = (!exists($options->{use_textcomp}) || $options->{use_textcomp});

    # If a list of exception characters was specified then we replace
    # those characters in the text string with something that is not
    # going to match the encoding regular expression.  The encoding we
    # use is a hex 01 byte followed by four hexadecimal digits

    if ($exceptions) {
        $exceptions =~ s{ \\ }{\\\\}gx;
        $text =~ s{ ([\x{01}$exceptions]) }
                                    { sprintf("\x{01}%04x", ord($1)); }gxe;
    }

    # Deal with "intelligent quotes".  This can be done separately
    # from the rest of the encoding as the characters ` and ' are not
    # encoded.

    if ($iquotes) {

        # A single or double quote before a word character, preceded
        # by start of line, whitespace or punctuation gets converted
        # to "`" or "``" respectively.

        $text =~ s{ ( ^ | [\s\p{IsPunct}] )( ['"] ) (?= \w ) }
                                    { $2 eq '"' ? "$1``" : "$1`" }mgxe;

        # A double quote preceded by a word or punctuation character
        # and followed by whitespace or end of line gets converted to
        # "''".  (Final single quotes are represented by themselves so
        # we don't need to worry about those.)

        $text =~ s{ (?<= [\w\p{IsPunct}] ) " (?= \s | $ ) }
                                    { "''" }mgxe
    }


    # Replace any characters that need encoding

    $text =~ s{ ($encoded_char_re)([\sa-zA-Z]?)}
                            { my $encoded  = $latex_encoding{$1};
                                my $nextchar = $2;
                                my $sepchars = "";
                                if ($nextchar and substr($encoded, -1) =~ /[a-zA-Z]/) {
                                        $sepchars = ($nextchar =~ /\s/) ? '{}' : ' ';
                                }
                                "$encoded$sepchars$nextchar" }gxe;


    # If the caller specified exceptions then we need to decode them

    if ($exceptions) {
        $text =~ s{ \x{01} ([0-9a-f]{4}) }{ chr(hex($1)) }gxe;
    }

    return $text;
}

1;

__END__

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