\s|^```|\*\*[^*\n]+\*\*|\[[^\]\n]+\]\([^)\s]+\)/m',
$text
);
}
public static function to_html( $text ) {
$text = str_replace( array( "\r\n", "\r" ), "\n", (string) $text );
$lines = explode( "\n", $text );
$html = array();
$para = array();
$count = count( $lines );
$flush = function () use ( &$para, &$html ) {
if ( $para ) {
$html[] = '' . implode( "
\n", array_map( array( __CLASS__, 'inline' ), $para ) ) . '
';
$para = array();
}
};
for ( $i = 0; $i < $count; $i++ ) {
$line = $lines[ $i ];
// Fenced code block.
if ( preg_match( '/^\s*```/', $line ) ) {
$flush();
$code = array();
for ( $i++; $i < $count && ! preg_match( '/^\s*```/', $lines[ $i ] ); $i++ ) {
$code[] = $lines[ $i ];
}
$html[] = '' . esc_html( implode( "\n", $code ) ) . '
';
continue;
}
if ( '' === trim( $line ) ) {
$flush();
continue;
}
if ( preg_match( '/^\s{0,3}(#{1,6})\s+(.+?)\s*#*\s*$/', $line, $m ) ) {
$flush();
$level = strlen( $m[1] );
$html[] = "" . self::inline( $m[2] ) . "";
continue;
}
if ( preg_match( '/^\s{0,3}([-*_])(\s*\1){2,}\s*$/', $line ) ) {
$flush();
$html[] = '
';
continue;
}
if ( preg_match( '/^\s{0,3}>\s?(.*)$/', $line ) ) {
$flush();
$quote = array();
while ( $i < $count && preg_match( '/^\s{0,3}>\s?(.*)$/', $lines[ $i ], $q ) ) {
$quote[] = $q[1];
++$i;
}
--$i;
$html[] = '' . self::to_html( implode( "\n", $quote ) ) . '
';
continue;
}
if ( self::list_item( $line ) ) {
$flush();
$html[] = self::render_list( $lines, $i );
continue;
}
$para[] = $line;
}
$flush();
return implode( "\n", $html );
}
/** @return array|null array( indent, ordered, text ) */
protected static function list_item( $line ) {
if ( preg_match( '/^(\s*)([-*+]|\d+[.)])\s+(.*)$/', $line, $m ) ) {
return array( strlen( str_replace( "\t", ' ', $m[1] ) ), ctype_digit( rtrim( $m[2], '.)' ) ), $m[3] );
}
return null;
}
/** Consume list lines from $i (left on the last list line). */
protected static function render_list( $lines, &$i ) {
$first = self::list_item( $lines[ $i ] );
$base = $first[0];
$tag = $first[1] ? 'ol' : 'ul';
$items = array();
$count = count( $lines );
for ( ; $i < $count; $i++ ) {
$item = self::list_item( $lines[ $i ] );
if ( ! $item ) {
// A non-blank, indented continuation line belongs to the last item.
if ( $items && '' !== trim( $lines[ $i ] ) && preg_match( '/^\s+/', $lines[ $i ] ) ) {
$items[ count( $items ) - 1 ]['text'] .= ' ' . trim( $lines[ $i ] );
continue;
}
break;
}
if ( $item[0] > $base && $items ) {
$items[ count( $items ) - 1 ]['sub'] = self::render_list( $lines, $i );
continue;
}
if ( $item[0] < $base ) {
break;
}
$items[] = array(
'text' => $item[2],
'sub' => '',
);
}
--$i;
$out = "<{$tag}>";
foreach ( $items as $item ) {
$out .= '' . self::inline( $item['text'] ) . $item['sub'] . '';
}
return $out . "";
}
/**
* A link or image target. esc_url() would turn a bare "photo.png" into
* "http://photo.png", and a bare filename is exactly how an image from the
* uploaded zip is referred to — so only absolute URLs go through it.
*/
protected static function url( $target ) {
return preg_match( '#^[a-z][a-z0-9+.-]*:|^//#i', $target ) ? esc_url( $target ) : esc_attr( $target );
}
/** Inline spans: code, images, links, bold, italic, strikethrough. */
public static function inline( $text ) {
$codes = array();
$text = preg_replace_callback(
'/`([^`]+)`/',
function ( $m ) use ( &$codes ) {
$codes[] = '' . esc_html( $m[1] ) . '';
return "\x1A" . ( count( $codes ) - 1 ) . "\x1A";
},
$text
);
$text = preg_replace_callback(
'/!\[([^\]]*)\]\(\s*([^)\s]+)(?:\s+"([^"]*)")?\s*\)/',
function ( $m ) {
return '![' . esc_attr( $m[1] ) . '](' . self::url( $m[2] ) . ' "' . esc_attr( $m[3] ) . '")
';
},
$text
);
$text = preg_replace_callback(
'/\[([^\]]+)\]\(\s*([^)\s]+)(?:\s+"([^"]*)")?\s*\)/',
function ( $m ) {
return '' . $m[1] . '';
},
$text
);
$text = preg_replace( '/<(https?:\/\/[^>\s]+)>/', '$1', $text );
$text = preg_replace( '/(\*\*|__)(?=\S)(.+?)(?<=\S)\1/', '$2', $text );
$text = preg_replace( '/(?$1', $text );
$text = preg_replace( '/(?$1', $text );
$text = preg_replace( '/~~(?=\S)(.+?)(?<=\S)~~/', '$1', $text );
return preg_replace_callback(
"/\x1A(\d+)\x1A/",
function ( $m ) use ( $codes ) {
return $codes[ (int) $m[1] ];
},
$text
);
}
}