DeclarationEvaluator.java

package com.drawbridge.jsengine.ast;

import java.util.LinkedList;

import com.drawbridge.jsengine.Scope;
import com.drawbridge.jsengine.SymbolTableEntry;
import com.drawbridge.jsengine.jsobjects.ExecutionException;
import com.drawbridge.jsengine.jsobjects.JSType;
import com.drawbridge.vl.blocks.BlockAssignment;
import com.drawbridge.vl.blocks.BlockDeclaration;
import com.google.caja.parser.js.Declaration;
import com.google.caja.parser.js.Expression;
import com.google.caja.parser.js.Identifier;

public class DeclarationEvaluator extends Evaluator
{

	public Identifier	identifier;
	public Expression	initialiser;

	/**
	 * Used to declare a var. No other types can be used (rules of Js).
	 * 
	 * @param parser
	 * @param declaration
	 */
	public DeclarationEvaluator(Evaluator parent, Scope scope, Declaration declaration) {
		super(parent, scope, declaration.getFilePosition());

		identifier = declaration.getIdentifier();
		initialiser = declaration.getInitializer();
		scope.declareVariableForStaticAnalysis(identifier);
		Evaluator initEval = Evaluator.getEvaluator(this, mScope, initialiser);
		mChildren.add(initEval);
	}

	@Override
	public JSType evaluate() throws EvaluatorException, ExecutionException
	{
		// Evaluate the initializer: could be primitive, or function call, etc.
		JSType initialiserResult = null;
		if (mChildren.get(0) != null)
		{
			// Utils.out.println("initialiser evaluator: " +
			// mChildren.get(0).getClass().getName());
			initialiserResult = mChildren.get(0).evaluate();
			// Utils.out.println("Attempted to add: " + ((initialiserResult ==
			// null) ? "NULL" : initialiserResult.toString()) +
			// " as the value for: " + identifier.getValue());
			try
			{
				mScope.declareVariable(null, identifier.getValue(), new SymbolTableEntry(initialiserResult, this.getFilePosition().startLineNo()));
			} catch (Exception e)
			{
				throw new EvaluatorException("DeclarationEvaluation error: SymbolTable Addition:" + e.getMessage());
			}
		}
		else
		{
			throw new RuntimeException("DeclarationEvaluator returned null!");
		}
		return null;
	}

	@Override
	public LinkedList<com.drawbridge.vl.blocks.Block> getBlocks()
	{
		LinkedList<com.drawbridge.vl.blocks.Block> results = new LinkedList<com.drawbridge.vl.blocks.Block>();
		BlockDeclaration db = new BlockDeclaration(identifier.getFilePosition(), this, identifier.getValue());
		results.add(db);
		if (mChildren != null && mChildren.size() > 0 && mChildren.get(0) != null)
		{
			BlockAssignment ab = new BlockAssignment(initialiser.getFilePosition(), null);
			ab.setFilePosition(identifier.getFilePosition());
			results.add(ab);
			LinkedList<com.drawbridge.vl.blocks.Block> childResult = ((mChildren.get(0) == null) ? null : mChildren.get(0).getBlocks());
			if (childResult != null)
				results.addAll(childResult);
		}
		return results;
	}

}