/**
* This method returns the specified processing instruction.
*
* @access public
* @param string $target the target name of the processing
* instruction
* @param integer $index the index of the processing instruction
* @return array the data associated with the target
* @throws Throwable\Parse\Exception indicates that an invalid token was
* encountered
*
* @see http://msdn.microsoft.com/en-us/library/ms256173%28v=vs.110%29.aspx
* @see http://www.w3schools.com/xsl/el_processing-instruction.asp
* @see http://pastebin.com/x25seJPS
* @see https://github.com/petertornstrand/tornstrand.com/blob/master/_posts/2008-10-21-reading-xml-processing-instruction-with-php.html
* @see http://java2s.com/Tutorials/PHP/XML_Functions/PHP_xml_set_processing_instruction_handler_Function.htm
* @see http://www.xml.com/pub/a/2000/09/13/xslt/
*/
public function getProcessingInstruction($target, $index = 1)
{
$document = dom_import_simplexml($this)->ownerDocument;
$xpath = new \DOMXPath($document);
$instruction = trim($xpath->evaluate("string(//processing-instruction(\"{$target}\")[{$index}])"));
$directives = array();
$scanner = new Lexer\Scanner(new IO\StringReader($instruction));
$scanner->addRule(new Lexer\Scanner\TokenRule\Symbol('='));
$scanner->addRule(new Lexer\Scanner\TokenRule\Keyword());
$scanner->addRule(new Lexer\Scanner\TokenRule\Literal('"'));
$scanner->addRule(new Lexer\Scanner\TokenRule\Whitespace());
$state = 0;
$key = null;
while ($scanner->next()) {
$tuple = $scanner->current();
if (Lexer\Scanner\TokenType::identifier()->__equals($tuple->type) && $state == 0) {
$state = 1;
$key = $tuple->token->__toString();
} else {
if (Lexer\Scanner\TokenType::symbol()->__equals($tuple->type) && $state == 1) {
$state = 2;
} else {
if (Lexer\Scanner\TokenType::literal()->__equals($tuple->type) && $state == 2) {
$state = 3;
$directives[$key] = $tuple->token->substring(1, $tuple->token->length() - 1)->__toString();
} else {
if (Lexer\Scanner\TokenType::whitespace()->__equals($tuple->type)) {
$state = 0;
} else {
throw new Throwable\Parse\Exception('Unable to parse processing instruction. Invalid token ":token" encountered with type ":type".', array(':token' => $tuple->token, ':type' => $tuple->type));
}
}
}
}
}
return $directives;
}
/**
* This method return a tuple representing the token discovered.
*
* @access public
* @param \Unicity\IO\Reader $reader the reader to be used
* @return \Unicity\Lexer\Scanner\Tuple a tuple representing the token
* discovered
*/
public function process(IO\Reader $reader)
{
$index = $reader->position();
$char = $reader->readChar($index, false);
if ($char == $this->quotation) {
$lookahead = $index + 1;
$length = $reader->length() - 1;
while ($lookahead <= $length) {
if ($reader->readChar($lookahead, false) == $this->quotation) {
if ($lookahead == $length || $reader->readChar($lookahead + 1, false) != $this->quotation) {
$lookahead++;
break;
}
$lookahead++;
}
$lookahead++;
}
$token = $reader->readRange($index, $lookahead);
$tuple = new Lexer\Scanner\Tuple(Lexer\Scanner\TokenType::literal(), new Common\String($token));
return $tuple;
}
return null;
}
