parser.java

实验软装置（基于表达式的计算器ExprEval） 很不错的 有帮助于学习提高

			}
		}
		else if(token.getType()==TokenType.GE){
			if(top>3&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))&&(stack[top-3].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.NUMBER||tmpexp[1].getType()!=TokenType.NUMBER){
					throw new exceptions.TypeMismatchedException();//type smatch
				}
				int ret=0;
				//System.out.println("ge: "+(boolean)(tmpexp[1].getValue()>tmpexp[0].getValue()));
				if(tmpexp[1].getValue()>=tmpexp[0].getValue())
					ret=1;
				Expression expr=new Expression("E",ret,ret,ret,TokenType.BOOL);
				stack[top-3]=expr;
				top-=2;
			}
			else{
				throw new exceptions.MissingOperandException();
			}
		}
		else if(token.getType()==TokenType.LE){
			if(top>3&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))&&(stack[top-3].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.NUMBER||tmpexp[1].getType()!=TokenType.NUMBER){
					throw new exceptions.TypeMismatchedException();//type smatch
				}
				int ret=0;
				//System.out.println("le: "+(boolean)(tmpexp[1].getValue()>tmpexp[0].getValue()));
				if(tmpexp[1].getValue()<=tmpexp[0].getValue())
					ret=1;
				Expression expr=new Expression("E",ret,ret,ret,TokenType.BOOL);
				stack[top-3]=expr;
				top-=2;
			}
			else{
				throw new exceptions.MissingOperandException();
			}
		}
		else if(token.getType()==TokenType.NEQUAL){
			if(top>3&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))&&(stack[top-3].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.NUMBER||tmpexp[1].getType()!=TokenType.NUMBER){
					throw new exceptions.TypeMismatchedException();///type smatch
				}
				int ret=0;
				//System.out.println("ne: "+(boolean)(tmpexp[1].getValue()>tmpexp[0].getValue()));
				if(tmpexp[1].getValue()!=tmpexp[0].getValue())
					ret=1;
				Expression expr=new Expression("E",ret,ret,ret,TokenType.BOOL);
				stack[top-3]=expr;
				top-=2;
			}
			else{
				throw new exceptions.MissingOperandException();
			}
		}
		else if(token.getType()==TokenType.EQUAL){
			if(top>3&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))&&(stack[top-3].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.NUMBER||tmpexp[1].getType()!=TokenType.NUMBER){
					throw new exceptions.TypeMismatchedException();///type smatch
				}
				int ret=0;
				//System.out.println("ne: "+(boolean)(tmpexp[1].getValue()>tmpexp[0].getValue()));
				if(tmpexp[1].getValue()==tmpexp[0].getValue())
					ret=1;
				Expression expr=new Expression("E",ret,ret,ret,TokenType.BOOL);
				stack[top-3]=expr;
				top-=2;
			}
			else{
				throw new exceptions.MissingOperandException();
			}
		}
		else if(token.getType()==TokenType.COMMA){
			if(top>3&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))&&(stack[top-3].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.NUMBER||(tmpexp[1].getType()!=TokenType.NUMBER&&tmpexp[1].getType()!=TokenType.COMMA)){
					throw new exceptions.TypeMismatchedException();//type smatch
				}
				double ret1=tmpexp[0].getMax();
				double ret2=tmpexp[0].getMin();
				//System.out.println("comma: ");
				
				if(tmpexp[1].getMax()>ret1)
					ret1=tmpexp[1].getMax();//max
				if(tmpexp[1].getMin()<ret2)
					ret2=tmpexp[1].getMin();//min
				Expression expr=new Expression("E",ret1,ret1,ret2,TokenType.COMMA);
				stack[top-3]=expr;
				top-=2;
			}
			else{
				throw new exceptions.MissingOperandException();
			}
		}
		else if(token.getType()==TokenType.MAX){
			if(top>2&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.COMMA){
					throw new exceptions.MissingOperandException();//type smatch
				}
				//System.out.println("max: ");
				Expression expr=new Expression("E",tmpexp[0].getMax(),tmpexp[0].getMax(),tmpexp[0].getMax(),TokenType.NUMBER);
				stack[top-2]=expr;
				top-=1;
			}
			else{
				throw new exceptions.FunctionCallException();
			}
		}
		else if(token.getType()==TokenType.MIN){
			if(top>2&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.COMMA){
					throw new exceptions.MissingOperandException();
				}
				//System.out.println("min: "+tmpexp[0].getMin());
				Expression expr=new Expression("E",tmpexp[0].getMin(),tmpexp[0].getMin(),tmpexp[0].getMin(),TokenType.NUMBER);
				stack[top-2]=expr;
				top-=1;
			}
			else{
				throw new exceptions.FunctionCallException();
			}
		}
		else if(token.getType()==TokenType.SIN){
			if(top>2&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.NUMBER&&tmpexp[0].getType()!=TokenType.COMMA){
					throw new exceptions.TypeMismatchedException();//type smatch
				}
				if(tmpexp[0].getType()==TokenType.COMMA){
					throw new exceptions.FunctionCallException();//type smatch
				}
				//System.out.println("sin: ");
				double ret=Math.sin(tmpexp[0].getValue());
				Expression expr=new Expression("E",ret,ret,ret,TokenType.NUMBER);
				stack[top-2]=expr;
				top-=1;
			}
			else{
				throw new exceptions.FunctionCallException();
			}
		}
		else if(token.getType()==TokenType.COS){
			if(top>2&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))){
				if(tmpexp[0].getType()!=TokenType.NUMBER&&tmpexp[0].getType()!=TokenType.COMMA){
					throw new exceptions.TypeMismatchedException();//type smatch
				}
				if(tmpexp[0].getType()==TokenType.COMMA){
					throw new exceptions.FunctionCallException();//type smatch
				}
				//System.out.println("cos: ");
				double ret=Math.cos(tmpexp[0].getValue());
				Expression expr=new Expression("E",ret,ret,ret,TokenType.NUMBER);
				stack[top-2]=expr;
				top-=1;
			}
			else{
				throw new exceptions.FunctionCallException();
			}
		}
		else if(token.getType()==TokenType.COLON){
			if(top>5&&(stack[top-1].getName().equals("E"))&&(!stack[top-2].getName().equals("E"))
					&&(stack[top-3].getName().equals("E"))&&(!stack[top-4].getName().equals("E"))
					&&(stack[top-5].getName().equals("E"))){
				if(((Token)stack[top-4]).getType()!=TokenType.QMARK){
					throw new exceptions.TrinaryOperationException();//no colon match
				}
				if(tmpexp[0].getType()!=TokenType.NUMBER||tmpexp[1].getType()!=TokenType.NUMBER||
						tmpexp[2].getType()!=TokenType.BOOL){
					throw new exceptions.TypeMismatchedException();//type smatch
				}
				//System.out.println("?: ");
				double ret=tmpexp[0].getValue();
				if(tmpexp[2].getValue()>0){
					ret=tmpexp[1].getValue();
				}
				Expression expr=new Expression("E",ret,ret,ret,TokenType.NUMBER);
				stack[top-5]=expr;
				top-=4;
			}
			else{
					throw new exceptions.TrinaryOperationException();

			}
		}		
	}
	
	/**
	 * parse
	 * @param input input string
	 * @throws IOException 
	 * @throws ExpressionException
	 */
	private void parse(String input) throws IOException,ExpressionException
	{
		stack=new Symbol[100];
		top=1;

		Token t=new Token("",0,-1,TokenType.getPriority(-1));
		boolean flag=true;
		scanner=new Scanner(input);
		stack[0]=t;
		while(true)
		{
			if(flag){
				lookahead=scanner.getNextToken();
			//	System.out.println("get: "+lookahead.getType());///////////
			}
			Token tmptoken=(Token)(stack[getTop()]);
			if(((Token)stack[getTop()]).getType()==TokenType.END&&lookahead.getType()==TokenType.END){
				accept();
				return;
			}
			else if(parserTable.isError(tmptoken.getType(), lookahead.getType())){
				throw parserTable.getError(tmptoken.getType(), lookahead.getType());
			}
			/*
			else if(tmptoken.getPriority()==lookahead.getPriority()){
				if(TokenType.isLeft(tmptoken.getType())){
					stack[top++]=lookahead;
					System.out.println("in stack:"+lookahead.getType());////////
					flag=true;
				}
				else{
					flag=true;
					
					System.out.print("reduced1:");//////////
					while(!TokenType.isShift(((Token)stack[getTop()]).getType(),lookahead.getType())){
						reduce();
						if(parserTable.isError(((Token)stack[getTop()]).getType(), lookahead.getType())){
							throw parserTable.getError(((Token)stack[getTop()]).getType(), lookahead.getType());
						}
						if(((Token)stack[getTop()]).getType()==TokenType.END&&lookahead.getType()==TokenType.END){
							accept();
							return;
						}
					}
					stack[top++]=lookahead;
					System.out.println("in stack:"+lookahead.getType());///////
				}
			}
			*/
			else if(parserTable.isShift(((Token)stack[getTop()]).getType(),lookahead.getType())){
				flag=true;
				stack[top++]=lookahead;
				//System.out.println("in stack:"+lookahead.getType());///////
			}
			else if(!parserTable.isShift(((Token)stack[getTop()]).getType(),lookahead.getType())){
				flag=true;
				
				while(!parserTable.isShift(((Token)stack[getTop()]).getType(),lookahead.getType())){
					//System.out.println("reduced2.1:"+((Token)stack[getTop()]).getType()+" "+lookahead.getType());//////////
					reduce();
					if(parserTable.isError(((Token)stack[getTop()]).getType(), lookahead.getType())){
						throw parserTable.getError(((Token)stack[getTop()]).getType(), lookahead.getType());
					}
					if(((Token)stack[getTop()]).getType()==TokenType.END&&lookahead.getType()==TokenType.END){
						accept();
						return;
					}
				}
				stack[top++]=lookahead;
				//System.out.println("in stack:"+lookahead.getType());///////
				
			}
		}
		
	}
	
	/**
	 * calculate an expression
	 * @param string input string
	 * @return result of expression
	 * @throws IOException
	 * @throws ExpressionException
	 */
	public double calculate(String string) throws IOException,ExpressionException
	{
		parse(string);
		System.out.println(fin.getValue());
		if(fin.getType()==TokenType.BOOL)
			throw new exceptions.TypeMismatchedException();
		return fin.getValue();
	}
	
	static public void main(String []args) throws IOException,Exception
	{
		Parser a=new Parser();

		a.calculate("max(5,8)=sin(2)?5:cos(5)<1?5+3:-4");
		
	}
	
}