/itexToMML

# itex2MML

# version 2.0

# copyright 2003-2019, Jacques Distler

#

package MT::Plugin::itex2MML;

use MT;

use MathML::itex2MML qw( itex_html_filter );

use vars qw( $VERSION );

$VERSION = '2.0';

eval{ require MT::Plugin;};

unless ($@) {

   my $plugin = {

      name => "itex2MML",

      version => $VERSION,

      description => "A Text-Filter, translating embedded itex equations into MathML",

      doc_link => 'http://golem.ph.utexas.edu/~distler/blog/itex2MML.html',

   };

   MT->add_plugin(new MT::Plugin($plugin));

}

MT->add_text_filter(itexToMML => {

	label => 'itex to MathML',

	on_format => sub { &itexToMML; },

});

MT->add_text_filter(itexToMMLpara => {

        label => 'itex to MathML with parbreaks',

        on_format => sub { &itexToMMLpara; },

});

my $itex2mml_number_equations = 1;

sub itexToMML {

    $_=shift;

    $ctx = shift;

    $_=~ s/\r//g;

    $_ = number_equations($_, $itex2mml_number_equations, $ctx);

    itex_html_filter($_);

}

sub itexToMMLpara {

    $_ = shift;

    $ctx = shift;

    $_=~ s/\r//g;

    $_ = number_equations($_, $itex2mml_number_equations, $ctx);

    $_ = splitparas($_);

    itex_html_filter($_);

}

sub splitparas {

    my $str = shift;

    $str ||= '';

    my @paras = split /\n{2,}/, $str;

    for my $p (@paras) {

        if ($p !~ m@^</?(?:h1|h2|h3|h4|h5|h6|table|ol|dl|ul|menu|dir|p|pre|center|form|fieldset|select|blockquote|address|div|hr)@) {

#        if ($p !~ m@^\s*</?(?:h1|h2|h3|h4|h5|h6|table|ol|dl|ul|menu|dir|p|pre|center|form|fieldset|select|blockquote|address|div|hr)@) {

            $p = "<p>$p</p>";

        }

    }

    join "\n\n", @paras;

}

sub number_equations {

  $_ = shift;

  my $arg_value = shift;

  my $ctx = shift;

  if ($arg_value == 0) {return $_;}

  my $prefix = "eq";

  if ((defined $ctx)  && (ref($ctx) eq 'MT::Template::Context')) {

    if ($ctx->stash('comment') ) {

       $prefix = "c" . $ctx->stash('comment')->id;

    } elsif ($ctx->stash('entry') ) {

       $prefix = "e" . $ctx->stash('entry')->id;

    }

  }

  my $cls = "numberedEq";

  my %eqnumber;

  my $eqno=1;

  # add equation numbers to \[...\]

  #  - introduce a wrapper-<div> and a <span> with the equation number

#  while (s/(^\s*)?\\\[(.*?)\\\]/\n\n$1<div class=\"$cls\"><span>\($eqno\)<\/span>\$\$$2\$\$<\/div>\n\n/s) {

  while (s/\\\[(.*?)\\\]/\n\n<div class=\"$cls\"><span>\($eqno\)<\/span>\$\$$1\$\$<\/div>\n\n/s) {

    $eqno++;

  }

  # assemble equation labels into a hash

  # - remove the \label{} command, collapse surrounding whitespace

  # - add an ID to the wrapper-<div>. prefix it to give a fighting chance

  #   for the ID to be unique

  # - hash key is the equation label, value is the equation number

  while (s/<div class=\"$cls\"><span>\((\d+)\)<\/span>\$\$((?:[^\$]|\\\$)*)\s*\\label{(\w*)}\s*((?:[^\$]|\\\$)*)\$\$<\/div>/<div class=\"$cls\" id=\"$prefix:$3\"><span>\($1\)<\/span>\$\$$2$4\$\$<\/div>/s) {

    $eqnumber{"$3"} = $1;

  }

  # add cross-references

  # - they can be either (eq:foo) or \eqref{foo}

  s/\(eq:(\w+)\)/\(<a href=\"#$prefix:$1\">$eqnumber{"$1"}<\/a>\)/g;

  s/\\eqref\{(\w+)\}/\(<a href=\'#$prefix:$1\'>$eqnumber{"$1"}<\/a>\)/g;

  return $_;

}

1;