programnode.java

是有关解释器的.用JAVA编写.可以解释一般的JAVA程序.

public class ProgramNode extends ExecutableNode 
{
	public static boolean vIsMainMethod= true;
	public static String vMessageReciever= null; 	
	public static Environment vTopLevelEnvironment= new Environment();
	MethodDefinitionNode[] vMethodDefinitionNodes;
	MainMethodNode vMainMethodNode;
	int vProgramCount;
	int vProgramSize;	

	/** This methods recognizes a task method within in the token stream **/
    static ProgramNode parseProgram(Environment env, Scanner s)throws ParserException, ScannerException
    {
        // Now we match the required tokens...
    	ProgramNode tmpProgramNode= new ProgramNode();
    	    	
        if(!MainMethodNode.mIsMainMethod(s))
        {
        	tmpProgramNode.mPushMethodDefinitionNode(MethodDefinitionNode.parserMethodDefinition(env,s));
        	while(!MainMethodNode.mIsMainMethod(s))
        		tmpProgramNode.mPushMethodDefinitionNode(MethodDefinitionNode.parserMethodDefinition(env,s));
        }
        tmpProgramNode.vMainMethodNode= MainMethodNode.parserMainMethod(env,s);
        if(isKeywordToken(s))
        {
        	tmpProgramNode.mPushMethodDefinitionNode(MethodDefinitionNode.parserMethodDefinition(env,s));
        	while(isKeywordToken(s))
        		tmpProgramNode.mPushMethodDefinitionNode(MethodDefinitionNode.parserMethodDefinition(env,s));
        }
        
        return tmpProgramNode;
    }
    static void mTypeCheckError(String clause)
    {
    	System.out.println(">>>>Type Check Error<<<<");
    	System.out.println("Statement: ");
		System.out.println("    "+clause);
		System.exit(1);
    }
    boolean mEmptyProgramBuf()
    {
    	return vProgramCount==0;
    }
    boolean mFullProgramBuf()
    {
    	return vProgramCount==vProgramSize;
    }
    void mPushMethodDefinitionNode(MethodDefinitionNode aMethodDefinitionNode)
    {
    	if(mFullProgramBuf())mAutoResizeProgramBuf();
    	vMethodDefinitionNodes[vProgramCount]= aMethodDefinitionNode;
    	vProgramCount++;
    }
    MethodDefinitionNode mPopMethodDefinitionNode()
    {
    	if(!mEmptyProgramBuf())
    	{
    		vProgramCount--;
    		return vMethodDefinitionNodes[vProgramCount];
    	}else return null;
    }
    void mResizeProgramBuf(int aNewProgramSize)
    {
    	if(aNewProgramSize > vProgramCount)
    	{
    		MethodDefinitionNode[] tmpMethodDefinitionNodes;
    		
    		tmpMethodDefinitionNodes= new MethodDefinitionNode[aNewProgramSize];
    		for(int i=0; i<vProgramCount; i++)
    			tmpMethodDefinitionNodes[i]= vMethodDefinitionNodes[i];
    		vMethodDefinitionNodes= tmpMethodDefinitionNodes;
    		vProgramSize= aNewProgramSize;
		}
    }
    void mAutoResizeProgramBuf()
    {
    	mResizeProgramBuf(vProgramSize*2);
    }
    /** Constructor for this class **/
    ProgramNode()
	{
    	vProgramCount= 0;
    	vProgramSize= 4;
    	vMethodDefinitionNodes= new MethodDefinitionNode[vProgramSize];
    	vMainMethodNode= null;
	}
    ProgramNode(int aProgramSize)
	{
    	vProgramCount= 0;
    	vProgramSize= aProgramSize;
    	vMethodDefinitionNodes= new MethodDefinitionNode[aProgramSize];
    	vMainMethodNode= null;
	}

    /** This methods should execute the saved program node. **/
    Environment run(Environment env) throws InterpreterException
    {
      // Here you can save a top-level-Environment by calling
      // Environment.setTopLevelEnv(env). It can be used by calling
      // Environment.getTopLevelEnv().
				    					    	
		env= vMainMethodNode.run(env);
      // finally call the run method of the saved statement.		
		return env;
    }


    String format(int indent)
    {
    	String str=	"/**********************************\n" +
    				" ****      GDI Praktikum       ****\n" +
					" ****        Gruppe 6          ****\n" +
					" **********************************/\n\n" +
					"// ############ BEGIN ############\n\n";
    	for(int i=0; i<vProgramCount; i++)
    		str+= "\n" + vMethodDefinitionNodes[i].format(indent);
    	str+= vMainMethodNode.format(indent);
    	str+= "\n\n// ############ END ############";
        return str;
    }

    // html pretty printing is optional
    String toHtml(int indent)
    {
        return "<pre>\n" +
               "<font color=\"#0000FF\">It</font> would be <u>nice</u>\n" +
               "  <b>if</b>\n"+
               "    <font color=\"#FF0000\">I</font>\n"+
               "  <b>were</b> implemented.\n" +
               "</pre>\n";
    }
    boolean typeCheck(Environment env) throws InterpreterException
	{
    	vTopLevelEnvironment.put("returnValue", "NOVALUE");//for method returns    	    	
    	vTopLevelEnvironment.put("returnType", "NOTYPE");
    	for(int i=0; i<vProgramCount; i++)
    		if(!vMethodDefinitionNodes[i].typeCheck(env.mCreateNewEnvironment()))return false;
    		
    	return vMainMethodNode.typeCheck(env);
	}
}