Very primitive filter lets your users use some of TeX/LaTeX commands in their postings.";
break;
}
return t($output);
}
/**
* Implementation of filter_filter().
*/
function latex_filter($op, $delta = 0, $format = -1, $text = '') {
switch ($op) {
case 'list':
return array(t('TeX/LaTeX'));
case 'description':
return t("Allows to use some elements of TeX/LaTeX.");
case 'settings':
$form['conf'] = array(
'#type' => 'fieldset',
'#title' => t('LaTeX filter'),
'#collapsible' => TRUE,
'#collapsed' => TRUE,
);
$form['conf']['latex_filter_link'] = array(
'#type' => 'select',
'#title' => t("Recognize TeX/LaTeX commands"),
'#default_value' => variable_get("latex_filter_link", 0),
'#options' => array(t("Show unknown commands"), t("Strip unknown commands")),
'#description' => t('Enable usage of TeX/LaTeX commands in user-distributed content.
If option set to "Strip unknown commands", then unrecognized TeX/LaTeX commands are not showed in output.
If option set to "Show unknown commands", then arguments of all unrecognized commands are showed in HTML-output.'),
);
$form['conf']['latex_custom_commands'] = array(
'#type' => 'textarea',
'#title' => t("Extend LaTeX filter with your custom commands"),
'#default_value' => variable_get("latex_custom_commands", ""),
//'#cols' => 70,
//'#rows' => 7,
'#description' => t('Define your custom regexps (one per line) like this example: \link{(.*)}{(.*)} <a href="$1">$2</a> - separate pattern part from replace parts with one space character. For inserting space in pattern part use numeric code "\040". '),
);
return $form;
case 'process':
return _latex_filter_process($text);
default:
return $text;
}
}
function _latex_filter_process($text) {
// Save verbatims from conversions:
$text = str_replace("\begin{verbatim}", "", $text);
$text = str_replace("\end{verbatim}", "", $text);
$text = preg_replace_callback("|(.*)
|smU", "_latex_hash_verbatim", $text);
// Convert some special characters:
$text = str_replace("\TeX", "TEX", $text);
$text = str_replace("\LaTeX", "LATEX", $text);
$text = str_replace("\copyright", "©", $text);
$text = str_replace("\dots", "…", $text);
$text = str_replace("\ldots", "…", $text);
$text = str_replace("\cdots", "…", $text);
$text = str_replace("\pm", "±", $text);
$text = str_replace("\div", "÷", $text);
$text = str_replace("\le", "≤", $text);
$text = str_replace("\ge", "≥", $text);
$text = str_replace("\lt", "<", $text);
$text = str_replace("\gt", ">", $text);
$text = str_replace("``", '“', $text);
$text = str_replace("''", '”', $text);
$text = str_replace("\;", " ", $text);
// BUG: next two lines never pass to filter if Drupal HTML filtering ON and strip unknown tags
$text = str_replace("<<", '«', $text);
$text = str_replace(">>", '»', $text);
$text = str_replace("~---", " —", $text); // I not sure for TeX standards for dash conversion, but Latex on my system eat such things and produce appropriate longdashes
$text = str_replace(" ---", " —", $text);
$text = str_replace(" --", " —", $text);
$text = str_replace("-{}-", "--", $text);
$text = str_replace("\ ", " ", $text);
// Custom commands (from `latex_custom_commands` site variable):
if ($lines = explode("\n", variable_get("latex_custom_commands", ""))) {
foreach ($lines as $line) {
if (! trim($line)) {
continue;
}
list($pattern, $command) = split(' ', $line, 2);
$text = preg_replace($pattern, $command, $text);
}
}
// TeX comments -> HTML comments
$text = preg_replace("/[^\\\]?%(.*)/iS", "", $text);
// Text blocks:
$text = str_replace("\begin{itemize}", "", $text);
$text = str_replace("\begin{list}", "", $text);
$text = str_replace("\begin{enumerate}", "", $text);
$text = str_replace("\begin{description}", "", $text);
$text = str_replace("\item", "
- ", $text);
$text = preg_replace("/\\\item{(.*)}/U", "
- $1", $text);
$text = str_replace("\end{description}", "", $text);
$text = str_replace("\end{enumerate}", "
", $text);
$text = str_replace("\end{list}", "
", $text);
$text = str_replace("\end{itemize}", "
", $text);
$text = preg_replace("/\\\begin{flush(left|right)}/U", '', $text);
$text = preg_replace("/\\\end{flush(left|right)}/U", '
', $text);
// Skip these commands:
$text = str_replace("\\\(begin|end){document}", "", $text);
$text = str_replace("\\\documentclass.*{.*})", "", $text);
$text = str_replace("\\\usepackage{.*}", "", $text);
$text = str_replace("\\\thispagestyle{.*}", "", $text);
$text = str_replace("\\\pagestyle{.*}", "", $text);
// Captions:
$text = preg_replace("/\\\section{(.*)}/U", "$1
", $text);
$text = preg_replace("/\\\subsection{(.*)}/U", "$1
", $text);
$text = preg_replace("/\\\subsubsection{(.*)}/U", "$1
", $text);
$text = preg_replace("/\\\subsubsubsection{(.*)}/U", "$1
", $text);
// Font styles:
$text = preg_replace("/{\\\(em|it) (.*)}/U", "$2", $text);
$text = preg_replace("/\\\\(emph|textit|textsl){(.*)}/U", "$2", $text);
$text = preg_replace("/{\\\\tt (.*)}/U", "$1", $text);
$text = preg_replace("/\\\\texttt{(.*)}/U", "$1", $text);
$text = preg_replace("/{\\\bf (.*)}/U", "$1", $text);
$text = preg_replace("/\\\\textbf{(.*)}/U", "$1", $text);
$text = preg_replace("/{\\\textsc (.*)}/U", "$1", $text);
// Footnotes:
preg_match_all("/\\\footnote{((.)(.*))}/uUms", $text, $footnotes);
if ($footnotes) {
$text = preg_replace_callback("/\\\footnote{((.)(.*))}/uUms", "_latex_hash_name", $text);
}
// Unknown commands visibility:
if (variable_get("latex_filter_link", 0) == 1) {
// ignore unknown commands:
$text = preg_replace("/\\\[a-z0-9\[\]]+{(.*)}/Ui", "", $text);
}
else {
// show unknown commands
$text = preg_replace("/\\\([a-z0-9\[\]]+){(.*)}/Ui", "\$1\{$2}", $text);
}
// Finally some miscellaneous conversions:
// $text = preg_replace("/(
|<\/h[1-9]>|<\/[uo]l>)\s*$^\s*/ms", "$1", $text); // new paragraph if command on next line (need testing)
//$text = preg_replace("/(.*)^\s*$/msU", "$1
", $text); // new paragraph in other cases
// $text = preg_replace("/\\\(.){}/U", "$1", $text); // any single char escaped with \{}
// $text = preg_replace("/\\\([#$%&_ ])/U", "$1", $text); // and other special chars
// BR-conversions commented out, because it now dealed with HTML-filter
$text = str_replace("\\", "
", $text); // EOL
$text = str_replace("\backslash", "\\", $text);
// Return to text previously saved verbatims:
foreach (_latex_hash_verbatim() as $key => $value) {
$text = str_replace($LATEX_VERBATIM_START_MAGIC. $key. $LATEX_VERBATIM_END_MAGIC, "". $value. "
", $text);
}
if($footnotes) {
$footnote = "
— ". $footnotes[1][$i]. "
";
}
$footnote .= "\n";
}
return $text . $footnote;
}
function _latex_hash_verbatim($matches = NULL) {
static $verbatim = array();
if ($matches) {
$verbatim = array(md5($matches[1]) => $matches[1]);
return $LATEX_VERBATIM_START_MAGIC. md5($matches[1]). $LATEX_VERBATIM_END_MAGIC;
} else {
return $verbatim;
}
}
function _latex_hash_name($matches) {
return "";
}
?>