Catgut
catgut.php
<?php
/*
Catgut knows xhtml so you don't have to. Relax. Take a rest.
Nick B-W <nick@panharmonicon.com>
Catgut takes a string containing simple, intuitive markdown, and converts it
to strict xhtml. It provides only the parsing engine -- storage, retrieval, and
integrity checking of user-submitted text is up to the containing script.
The markdown is easily extended, and can be modified on a per-object basis --
examine the ->filters array of the catgut object class. This also includes
built-in documentation of the default markdown tags.
Copyright (c) 2005, Nick Blanchard-Wright
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of the Panharmonicon nor the names of its contributors may
be used to endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
class catgut {
function catgut($string, $headerlevel=0) {
$this->string = $string; // Hurray!
$this->headerlevel = $headerlevel;
$this->filters = array( // Have some defaults.
// Get it? They're regular expressions!
'contractions' => array(
're' => "/(\D)'(\w{1,2})\b/",
'replace' => '$1’$2',
'description' => "foo'd becomes foo’d"
),
'possessive' => array(
're' => "/s'\B/",
'replace' => 's’',
'description' => "foos' bar becomes foos’ bar"
),
'doublequotes' => array(
're' => '/\B"(\w(\d"|.)*)"\B/U',
'replace' => '“$1”',
'description' => '"foo" becomes “foo”'
),
'singlequotes' => array(
're' => "/\B'(\w(\d'|.)*)'\B/U",
'replace' => '‘$1’',
'description' => "'foo' becomes ‘foo’"
),
'ellipses' => array(
're' => '/\.{3}/',
'replace' => '…',
'description' => 'foo ... bar becomes foo … bar'
),
'endash' => array(
're' => '/(\s)--(\s)/',
'replace' => '$1–$2',
'description' => 'foo -- bar becomes foo – bar'
),
'emdash' => array(
're' => '/(\w)--(\w)/',
'replace' => '$1—$2',
'description' => 'foo--bar becomes foo—bar'
),
'newline' => array(
're' => '/(.)\n(.)/',
'replace' => "$1\n<br />\n$2",
'description' => 'foo\nbar becomes foo\n<br />\nbar'
),
'strong' => array(
're' => '/(\B)-(.*[^-].*)-(\B)/U',
'open' => '<strong>',
'close' => '</strong>',
'description' => '-foo- becomes <strong>foo</strong>'
),
'em' => array(
're' => '/(^|[^:\/]\B)\/(.+)\/(\B)/U',
'open' => '<em>',
'close' => '</em>',
'description' => '/foo/ becomes <em>foo</em>'
),
'cite' => array(
're' => '/(\W)_(.+)_(\W)/U',
'open' => '<cite>',
'close' => '</cite>',
'description' => '_foo_ becomes <cite>foo</cite>'
),
'paragraph' => array(
're' => '/(^|\n{2,})(.*\S.*)(?=\n{2,}|$)/Us',
'open' => '<p>',
'close' => '</p>',
'description' => 'foo\n\n becomes <p>foo</p>'
),
'blockquote' => array(
're' => '/&openparagraph;(\t+)(.+)&closeparagraph;/Us',
'open' => '<blockquote>',
'close' => '</blockquote>',
'description' => '\tfoo becomes <blockquote>foo</blockquote>'
),
'header' => array(
're' => '/&openparagraph;(!+?)(.+)&closeparagraph;/Us',
'open' =>'<h1>',
'close' => '</h1>',
'callback' => 'header',
'description' => '!foo becomes <h1>foo</h1>'
),
'horizontalrule' => array(
're' => '/&openparagraph;-{4,}&closeparagraph;/Us',
'replace' => '<hr />',
'description' => '--------- becomes <hr />'
),
'link' => array(
're' => '/\[(.+)\]/U',
'callback' => 'link',
'description' => '[foo|bar] becomes <a href="foo">bar</a>'
)
);
}
function transform() {
// The basics.
$string = str_replace("\r\n", "\n", $this->string); // Lousy Windows
$string = str_replace("\r", "\n", $string); // Lousy Apple
$string = preg_replace("/ {4,}/", "\t", $string); // I like tabs.
$string = preg_replace('/^\s+$/m', "", $string); // Empty lines should be empty
$string = htmlentities($string, ENT_NOQUOTES); // Mmm.
// The fun part.
foreach($this->filters as $name=>$filter) {
if(isset($filter['callback'])) {
$string = preg_replace_callback($filter['re'], array($this, $filter['callback']), $string);
} elseif(isset($filter['replace'])) {
$string = preg_replace($filter['re'], $filter['replace'], $string);
} elseif(isset($filter['open']) and isset($filter['close'])) {
$string = preg_replace($filter['re'], "$1&open$name;$2&close$name;$3", $string);
}
}
// Clean up for open/close style filters.
$string = preg_replace_callback('/&(open|close)(.+);/U', array($this, 'replace'), $string);
return($string);
}
// Track header levels
function header($string) {
$headn = strlen($string[1]);
if(isset($this->headerlevel) and is_int($this->headerlevel)) { $headn = $headn + abs($this->headerlevel); }
if($headn > 6) { $headn = 6; }
$open = str_replace('<h1', "<h$headn", $this->filters['header']['open']);
$close = str_replace('h1>', "h$headn>", $this->filters['header']['close']);
return($open . $string[2] . $close);
}
// Bracket links are easy on the n00bs.
function link($string) {
$link = explode("|", $string[1]);
if(count($link) > 1) {
$text = array_pop($link);
}
$link = implode("|", $link);
$return = "<a href=\"";
if(preg_match("/^[^:]+@[^:]+$/", $link)) {
$return = $return . "mailto:";
$return = $return . $link . "\">";
} else {
$return = $return . $link . "\">";
}
if(!$text) {
$text = $link;
}
$return = $return . $text . "</a>";
return($return);
}
// The $open array enforces nesting.
function replace($string) {
static $open = array();
if($string[1] == 'open') {
array_unshift($open, $string[2]);
return($this->filters[$string[2]]['open']);
} elseif($string[1] == 'close') {
if(count($open)) {
$return = '';
$nested = array();
while($open[0] != $string[2]) {
$now = array_shift($open);
$nested[] = $now;
$return .= $this->filters[$now]['close'];
}
array_shift($open);
$return .= $this->filters[$string[2]]['close'];
foreach($nested as $nest) {
$return .= $this->filters[$nest]['open'];
array_unshift($open, $nest);
}
return($return);
}
}
return('');
}
}
?>