IReductionContext.java

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 * Version: GPL 3
 *
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package com.aptana.ide.parsing.bnf;

import com.aptana.ide.parsing.IParser;

/**
 * @author Kevin Lindsey
 */
public interface IReductionContext
{
	/**
	 * Returns the name of the action associated with this rule that caused a reduction handler to fire
	 * 
	 * @return
	 */
	String getAction();

	/**
	 * Returns the node at the given index. Indexes correspond to the position of the terminals and non-terminals for
	 * the rule that matched. Nodes are zero-indexed
	 * 
	 * @param index
	 * @return Returns null if the index is invalid
	 */
	Object getNode(int index);

	/**
	 * Returns a node with the given alias. If more than one terminal or non-terminal have the same alias, the item
	 * furthest to the left will be returned. Use getNode(String, int) to nodes to the right of that node. Returns null
	 * 
	 * @param name
	 * @return Returns null if the name does not exist
	 */
	Object getNode(String name);

	/**
	 * Returns the nth node with the given alias. Index corresponds to the nth terminal or non-terminal in the rule
	 * having the name specified. The first item with the alias begins with a zero index.
	 * 
	 * @param name
	 * @param index
	 * @return Returns null if the name does not exist of if the index is invalid
	 */
	Object getNode(String name, int index);

	/**
	 * Returns the number of nodes in this context
	 * 
	 * @return
	 */
	int getNodeCount();

	/**
	 * Returns all nodes in this context
	 * 
	 * @return
	 */
	Object[] getNodes();

	/**
	 * Returns a reference to the parser associated with this handler
	 * 
	 * @return
	 */
	IParser getParser();

	/**
	 * Returns the name of the production in the BNF grammar that has matched
	 * 
	 * @return
	 */
	String getProductionName();
	
	/**
	 * Set the nodes that are active within this context
	 * 
	 * @param nodes
	 */
	void setNodes(Object[] nodes);
}