, where Markdown is not escaped.
* @return string
*/
protected function children_md( $node, $in_code = false ) {
$out = '';
foreach ( $node->childNodes as $child ) {
$out .= $this->node_to_md( $child, $in_code );
}
return $out;
}
/**
* @param \DOMNode $node
* @param bool $in_code
* @return string
*/
protected function node_to_md( $node, $in_code = false ) {
if ( XML_TEXT_NODE === $node->nodeType ) {
$text = preg_replace( '/\s+/', ' ', $node->nodeValue );
return $in_code ? $text : $this->escape( $text );
}
if ( XML_ELEMENT_NODE !== $node->nodeType ) {
return '';
}
$tag = strtolower( $node->nodeName );
// BetterDocs code snippets carry their own toolbar and line-number column;
// the toolbar is already pruned, so emit just the code with its language.
if ( 'div' === $tag && $this->node_has_class( $node, 'betterdocs-code-snippet-wrapper' ) ) {
return $this->fence( $node->textContent, $node->getAttribute( 'data-language' ) );
}
$inner = $this->children_md( $node, $in_code );
switch ( $tag ) {
case 'h1':
case 'h2':
case 'h3':
case 'h4':
case 'h5':
case 'h6':
return "\n\n" . str_repeat( '#', (int) substr( $tag, 1 ) ) . ' ' . trim( $inner ) . "\n\n";
case 'p':
return "\n\n" . trim( $inner ) . "\n\n";
case 'br':
return " \n";
case 'hr':
return "\n\n---\n\n";
case 'strong':
case 'b':
return '' === trim( $inner ) ? '' : '**' . trim( $inner ) . '**';
case 'em':
case 'i':
return '' === trim( $inner ) ? '' : '*' . trim( $inner ) . '*';
case 'del':
case 's':
case 'strike':
return '' === trim( $inner ) ? '' : '~~' . trim( $inner ) . '~~';
case 'mark':
return trim( $inner );
case 'kbd':
case 'samp':
return '`' . trim( $node->textContent ) . '`';
case 'sup':
return '^' . trim( $inner );
case 'sub':
return '~' . trim( $inner );
case 'a':
$href = $node->getAttribute( 'href' );
$text = trim( $inner );
if ( '' === $href ) {
return $text;
}
return '[' . ( '' === $text ? $href : $text ) . '](' . $href . ')';
case 'img':
$src = $node->getAttribute( 'src' );
return '' === $src ? '' : '';
case 'figure':
return "\n\n" . trim( $inner ) . "\n\n";
case 'figcaption':
return '' === trim( $inner ) ? '' : "\n" . trim( $inner ) . "\n";
case 'iframe':
$src = $node->getAttribute( 'src' );
if ( '' === $src ) {
return '';
}
$label = $node->getAttribute( 'title' );
return "\n\n[" . ( '' === $label ? $src : $this->escape( $label ) ) . '](' . $src . ")\n\n";
case 'code':
// Inline code only; fenced blocks are handled by .
return '`' . trim( $node->textContent ) . '`';
case 'pre':
return $this->fence( $node->textContent, $this->language_of( $node ) );
case 'blockquote':
$quote = trim( $this->children_md( $node, $in_code ) );
return "\n\n" . preg_replace( '/^/m', '> ', $quote ) . "\n\n";
case 'ul':
return "\n\n" . $this->list_md( $node, false ) . "\n\n";
case 'ol':
return "\n\n" . $this->list_md( $node, true ) . "\n\n";
case 'table':
return $this->table_md( $node );
case 'dl':
return "\n\n" . trim( $inner ) . "\n\n";
case 'dt':
return "\n" . '**' . trim( $inner ) . '**' . "\n";
case 'dd':
return ': ' . trim( $inner ) . "\n";
default:
return $inner; // unwrap unknown containers (div/span/section/…)
}
}
/**
* Escape the Markdown metacharacters that would otherwise reformat prose.
*
* Intra-word underscores are deliberately left alone: CommonMark does not treat
* them as emphasis, so escaping them only makes identifiers like `my_var` uglier
* for the model reading them.
*
* @param string $text
* @return string
*/
protected function escape( $text ) {
return preg_replace( '/([\\\\`\*\[\]])/', '\\\\$1', (string) $text );
}
/**
* @param \DOMNode $node
* @param string $class
* @return bool
*/
protected function node_has_class( $node, $class ) {
if ( ! $node instanceof \DOMElement ) {
return false;
}
return in_array( $class, preg_split( '/\s+/', trim( $node->getAttribute( 'class' ) ) ), true );
}
/**
* Language hint for a fenced block, read from the usual `language-*` class on
* the or its child .
*
* @param \DOMNode $node
* @return string
*/
protected function language_of( $node ) {
$candidates = [ $node ];
foreach ( $node->childNodes as $child ) {
if ( XML_ELEMENT_NODE === $child->nodeType && 'code' === strtolower( $child->nodeName ) ) {
$candidates[] = $child;
}
}
foreach ( $candidates as $candidate ) {
if ( ! $candidate instanceof \DOMElement ) {
continue;
}
if ( preg_match( '/(?:language|lang|brush:)[-\s]([a-z0-9#+_-]+)/i', $candidate->getAttribute( 'class' ), $m ) ) {
return strtolower( $m[1] );
}
}
return '';
}
/**
* @param string $code
* @param string $language
* @return string
*/
protected function fence( $code, $language = '' ) {
$code = rtrim( ltrim( (string) $code, "\r\n" ) );
if ( '' === trim( $code ) ) {
return '';
}
// Use a longer fence when the snippet itself contains a triple backtick.
$fence = preg_match( '/^\s*```/m', $code ) ? '````' : '```';
return "\n\n" . $fence . $language . "\n" . $code . "\n" . $fence . "\n\n";
}
/**
* @param \DOMNode $node The / element.
* @param bool $ordered
* @return string
*/
protected function list_md( $node, $ordered ) {
$lines = [];
$index = 1;
foreach ( $node->childNodes as $li ) {
if ( XML_ELEMENT_NODE !== $li->nodeType || 'li' !== strtolower( $li->nodeName ) ) {
continue;
}
$marker = $ordered ? ( $index++ . '. ' ) : '- ';
$content = trim( $this->children_md( $li ) );
// Collapse blank lines inside the item so a nested list attaches directly
// under its parent marker, then indent continuation lines to the marker
// width (2 for "- ", 3 for "1. ").
$content = preg_replace( "/\n{2,}/", "\n", $content );
$content = str_replace( "\n", "\n" . str_repeat( ' ', strlen( $marker ) ), $content );
$lines[] = $marker . $content;
}
return implode( "\n", $lines );
}
/**
* Convert a to a GFM pipe table. Falls back to unwrapped text when the
* table has no rows we can line up.
*
* @param \DOMNode $node
* @return string
*/
protected function table_md( $node ) {
$dom = $node->ownerDocument;
$rows = [];
$tr_nodes = ( new \DOMXPath( $dom ) )->query( './/tr', $node );
if ( ! $tr_nodes || 0 === $tr_nodes->length ) {
return "\n\n" . trim( $this->children_md( $node ) ) . "\n\n";
}
foreach ( $tr_nodes as $tr ) {
$cells = [];
foreach ( $tr->childNodes as $cell ) {
if ( XML_ELEMENT_NODE !== $cell->nodeType ) {
continue;
}
$name = strtolower( $cell->nodeName );
if ( 'td' !== $name && 'th' !== $name ) {
continue;
}
// A pipe table cell is a single line; a literal pipe must be escaped.
$text = trim( preg_replace( "/\s*\n\s*/", ' ', $this->children_md( $cell ) ) );
$cells[] = str_replace( '|', '\|', $text );
}
if ( $cells ) {
$rows[] = $cells;
}
}
if ( ! $rows ) {
return '';
}
$columns = max( array_map( 'count', $rows ) );
$header = array_shift( $rows );
$header = array_pad( $header, $columns, '' );
$out = '| ' . implode( ' | ', $header ) . " |\n";
$out .= '| ' . implode( ' | ', array_fill( 0, $columns, '---' ) ) . " |\n";
foreach ( $rows as $row ) {
$out .= '| ' . implode( ' | ', array_pad( $row, $columns, '' ) ) . " |\n";
}
return "\n\n" . rtrim( $out ) . "\n\n";
}
}
`````