/**
* @param Expression $expression
* @param HierarchyVisitor $visitor
* @return bool
*/
public function depthFirstHierarchicWalk(Expression $expression, HierarchyVisitor $visitor)
{
$hierarchicVisitDispatcher = new HierachicalVisitDispatcher($visitor);
$walker = new DepthFirstStackBasedWalker();
$walkState = $walker->walk($expression, $hierarchicVisitDispatcher);
return $walkState;
}
/**
* @param Expression $e
* @param \Helstern\Nomsky\Grammar\Transformations\EliminateOptionals\OptionalsEliminator $visitor
*
* @return Expression|null
*/
public function walkAndVisitExpression(Expression $e, OptionalsEliminator $visitor)
{
$hierarchicVisitDispatcher = new CompleteVisitDispatcher($visitor);
$walker = new DepthFirstStackBasedWalker();
$walker->walk($e, $hierarchicVisitDispatcher);
$walkResult = $visitor->getRoot();
return $walkResult;
}
public function findFirst(SymbolPredicate $predicate)
{
$findFirstStateMachine = new FindFirstStateMachine($predicate);
$walker = new DepthFirstStackBasedWalker($findFirstStateMachine);
$expression = $this->getExpression();
$walker->walk($expression, NoDispatchDispatcher::singletonInstance());
$found = $findFirstStateMachine->getExpression();
return $found;
}
/**
* @param Expression $e
* @param NonTerminalNamingStrategy $namingStrategy
*
*@return Expression|null
*/
public function getDepthFirstWalkResult(Expression $e, NonTerminalNamingStrategy $namingStrategy)
{
$visitor = new OptionalsEliminator($namingStrategy);
$hierarchicVisitDispatcher = new CompleteVisitDispatcher($visitor);
$walker = new DepthFirstStackBasedWalker();
$walker->walk($e, $hierarchicVisitDispatcher);
$walkResult = $visitor->getRoot();
return $walkResult;
}
/**
* @param Expression $e
*
* @return Expression|null
*/
public function getDepthFirstWalkResult(Expression $e)
{
$visitor = new Visitor();
$hierarchicVisitDispatcher = new CompleteVisitDispatcher($visitor);
$walker = new DepthFirstStackBasedWalker();
$walker->walk($e, $hierarchicVisitDispatcher);
$walkResult = $visitor->getRoot();
return $walkResult;
}
/**
* @param Production $production
* @return array|Production[]
*/
public function transform(Production $production)
{
$expression = $production->getExpression();
$visitor = new Visitor();
$hierarchicVisitDispatcher = new CompleteVisitDispatcher($visitor);
$walker = new DepthFirstStackBasedWalker();
$walker->walk($expression, $hierarchicVisitDispatcher);
$rootExpression = $visitor->getRoot();
$production = new StandardProduction($production->getNonTerminal(), $rootExpression);
return array($production);
}
/**
* @param Production $initialProduction
* @return array|Production[]
*/
public function transform(Production $initialProduction)
{
$expression = $initialProduction->getExpression();
$visitor = new OptionalsEliminator($this->nonTerminalNamingStrategy);
$hierarchicVisitDispatcher = new CompleteVisitDispatcher($visitor);
$walker = new DepthFirstStackBasedWalker();
$walker->walk($expression, $hierarchicVisitDispatcher);
$visitRoot = $visitor->getRoot();
$cleanedProduction = new StandardProduction($initialProduction->getNonTerminal(), $visitRoot);
$cleanedProductionsList = array($cleanedProduction);
$cleanedProductionsList = array_merge($cleanedProductionsList, $visitor->getEpsilonAlternatives());
return $cleanedProductionsList;
}
/**
* @param Expression $e
*
* @return Expression|null
*/
public function getDepthFirstWalkResult(Expression $e)
{
$visitors = [new EliminateGroups\Visitor(), new EliminateNesting\Visitor()];
$walkResult = $e;
foreach ($visitors as $visitor) {
$hierarchicVisitDispatcher = new CompleteVisitDispatcher($visitor);
$walker = new DepthFirstStackBasedWalker();
$walker->walk($walkResult, $hierarchicVisitDispatcher);
if ($visitor instanceof EliminateGroups\Visitor | $visitor instanceof EliminateNesting\Visitor) {
$walkResult = $visitor->getRoot();
}
}
return $walkResult;
}
