_MarkdownExtra_TmpImpl::doAnchors PHP Method

    protected function doAnchors($text)
    {
        #
        # Turn Markdown link shortcuts into XHTML <a> tags.
        #
        if ($this->in_anchor) {
            return $text;
        }
        $this->in_anchor = true;
        #
        # First, handle reference-style links: [link text] [id]
        #
        $text = preg_replace_callback('{
			(					# wrap whole match in $1
			  \\[
				(' . $this->nested_brackets_re . ')	# link text = $2
			  \\]

			  [ ]?				# one optional space
			  (?:\\n[ ]*)?		# one optional newline followed by spaces

			  \\[
				(.*?)		# id = $3
			  \\]
			)
			}xs', array($this, '_doAnchors_reference_callback'), $text);
        #
        # Next, inline-style links: [link text](url "optional title")
        #
        $text = preg_replace_callback('{
			(				# wrap whole match in $1
			  \\[
				(' . $this->nested_brackets_re . ')	# link text = $2
			  \\]
			  \\(			# literal paren
				[ \\n]*
				(?:
					<(.+?)>	# href = $3
				|
					(' . $this->nested_url_parenthesis_re . ')	# href = $4
				)
				[ \\n]*
				(			# $5
				  ([\'"])	# quote char = $6
				  (.*?)		# Title = $7
				  \\6		# matching quote
				  [ \\n]*	# ignore any spaces/tabs between closing quote and )
				)?			# title is optional
			  \\)
			  (?:[ ]? ' . $this->id_class_attr_catch_re . ' )?	 # $8 = id/class attributes
			)
			}xs', array($this, '_doAnchors_inline_callback'), $text);
        #
        # Last, handle reference-style shortcuts: [link text]
        # These must come last in case you've also got [link text][1]
        # or [link text](/foo)
        #
        $text = preg_replace_callback('{
			(					# wrap whole match in $1
			  \\[
				([^\\[\\]]+)		# link text = $2; can\'t contain [ or ]
			  \\]
			)
			}xs', array($this, '_doAnchors_reference_callback'), $text);
        $this->in_anchor = false;
        return $text;
    }