/**
* Parse current rule.
*
* @param \Hoa\Compiler\Llk\Rule $zeRule Current rule.
* @param int $next Next rule index.
* @return bool
*/
protected function _parse(Rule $zeRule, $next)
{
if ($zeRule instanceof Rule\Token) {
$name = $this->getCurrentToken();
if ($zeRule->getTokenName() !== $name) {
return false;
}
$value = $this->getCurrentToken('value');
if (0 <= ($unification = $zeRule->getUnificationIndex())) {
for ($skip = 0, $i = count($this->_trace) - 1; $i >= 0; --$i) {
$trace = $this->_trace[$i];
if ($trace instanceof Rule\Entry) {
if (false === $trace->isTransitional()) {
if ($trace->getDepth() <= $this->_depth) {
break;
}
--$skip;
}
} elseif ($trace instanceof Rule\Ekzit && false === $trace->isTransitional()) {
$skip += $trace->getDepth() > $this->_depth;
}
if (0 < $skip) {
continue;
}
if ($trace instanceof Rule\Token && $unification === $trace->getUnificationIndex() && $value !== $trace->getValue()) {
return false;
}
}
}
$namespace = $this->getCurrentToken('namespace');
$zzeRule = clone $zeRule;
$zzeRule->setValue($value);
$zzeRule->setNamespace($namespace);
if (isset($this->_tokens[$namespace][$name])) {
$zzeRule->setRepresentation($this->_tokens[$namespace][$name]);
} else {
foreach ($this->_tokens[$namespace] as $_name => $regex) {
if (false === ($pos = strpos($_name, ':'))) {
continue;
}
$_name = substr($_name, 0, $pos);
if ($_name === $name) {
break;
}
}
$zzeRule->setRepresentation($regex);
}
array_pop($this->_todo);
$this->_trace[] = $zzeRule;
$this->_errorState = ++$this->_currentState;
return true;
} elseif ($zeRule instanceof Rule\Concatenation) {
if (false === $zeRule->isTransitional()) {
++$this->_depth;
}
$this->_trace[] = new Rule\Entry($zeRule->getName(), 0, null, $this->_depth);
$content = $zeRule->getContent();
for ($i = count($content) - 1; $i >= 0; --$i) {
$nextRule = $content[$i];
$this->_todo[] = new Rule\Ekzit($nextRule, 0);
$this->_todo[] = new Rule\Entry($nextRule, 0);
}
return true;
} elseif ($zeRule instanceof Rule\Choice) {
$content = $zeRule->getContent();
if ($next >= count($content)) {
return false;
}
if (false === $zeRule->isTransitional()) {
++$this->_depth;
}
$this->_trace[] = new Rule\Entry($zeRule->getName(), $next, $this->_todo, $this->_depth);
$nextRule = $content[$next];
$this->_todo[] = new Rule\Ekzit($nextRule, 0);
$this->_todo[] = new Rule\Entry($nextRule, 0);
return true;
} elseif ($zeRule instanceof Rule\Repetition) {
$nextRule = $zeRule->getContent();
if (0 === $next) {
$name = $zeRule->getName();
$min = $zeRule->getMin();
if (false === $zeRule->isTransitional()) {
++$this->_depth;
}
$this->_trace[] = new Rule\Entry($name, $min, null, $this->_depth);
array_pop($this->_todo);
$this->_todo[] = new Rule\Ekzit($name, $min, $this->_todo);
for ($i = 0; $i < $min; ++$i) {
$this->_todo[] = new Rule\Ekzit($nextRule, 0);
$this->_todo[] = new Rule\Entry($nextRule, 0);
}
return true;
} else {
$max = $zeRule->getMax();
if (-1 != $max && $next > $max) {
return false;
}
$this->_todo[] = new Rule\Ekzit($zeRule->getName(), $next, $this->_todo);
$this->_todo[] = new Rule\Ekzit($nextRule, 0);
$this->_todo[] = new Rule\Entry($nextRule, 0);
return true;
}
}
return false;
}