import java.util.*;
import java.*;
import java.io.*;

public class Parser
{
	private Scanner my_scanner;
	private PrintWriter output;

	//This scanner gets the input numbers from input_values file.
	java.util.Scanner input_list;

    // Store all the IDENTS ID and their values here
    private Hashtable variables = new Hashtable();

	public Parser(String input_file, String input_values, String output_file)
	{
		my_scanner = new Scanner(input_file);
		output = new PrintWriter(new FileOutputStream(new File(output_file)), true);
		input_list = new java.util.Scanner(new File(input_values));

	}

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	public void code_interpreter()
	{
		computation();

		// Add the necessary code

		output.close();
	}

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	/* This is the first method that should be called for parsing
	** The program should of the form "main" [ varDecl ] "{" statSequence "}" "."
	** If this template is violated in the input program, a parsing error should be generated
	*/

	public void computation()
	{
		//To be completed
    }


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    /*
    ** This method is responsible for parsing variable declaration list and populating the list of the defined variables.
    ** Variable decleration should have the form of "var" ident {"," ident } ";" An error should be generated if this form is violated.
    */
    public void varDecl()
    {
    	//To be completed
    }

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    /*
    ** Parse statSequence: statement {";" statement }.
    */
    public void statSequence()
    {
		//To be completed
    }

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	/*
	** Parse statement: assignment | funcCall | ifStatement
	*/

    public void statement()
    {
		int token = my_scanner.GetSym();
		//Be aware that if you're using GetSym method, you are actually reading the token and advancing to the next token.
		//This means that if the token you read is "let" the next time you call GetSym you will read the next token in the input file

        // Check for assignment
        if (token == 100)
            assignment();

        // Check for function call
        else if (token == 101)
            funcCall();

        // check for if statement
        else if (token == 102)
            ifStatement();

        else
            Error("The statement is neither an assignment or a function call or an \"if\" statement" );
    }

//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

	/*
	** Parse ifStatement: "if" relation "then" statSequence [ "else" statSequence ] "fi"
	*/

    public void ifStatement()
    {
		//To be completed
    }

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	/*
	** "call" ident [ "(" [expression { "," expression } ] ")" ]
	**
	** If the called function is OutputNum or OutputNewLine then the return value of the function is assumed to be 0.
	*/

    public int funcCall()
    {
		int temp = my_scanner.GetSym();

		if (temp != 61)
			Error("After \"call\" identifier of a function should be mentioned!");

		if((my_scanner.Id2String(my_scanner.id)).compareTo("InputNum") == 0)
			return InputNum();

		if((my_scanner.Id2String(my_scanner.id)).compareTo("OutputNum") == 0)
			OutputNum();

		else if((my_scanner.Id2String(my_scanner.id)).compareTo("OutputNewLine") == 0)
			OutputNewLine();

		return 0;
    }

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	/*
	** Parse assignment: "let" ident "<-" expression
	** make sure that you update the value of the variable which has been assigned to!
	*/

    public void assignment()
    {
        //To be completed
    }

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	/*
	** Parse relation: expression relOp expression
	** The output of the relation will determine if you need to execute the statement sequence after then or
	** the statement sequence after else (if there is any!)
	*/

    public bool relation()
    {
        //To be completed
    }

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	/*
	** Parse expression: term {("+"|"-") term}
	*/
    public int expression()
    {
        //To be completed
    }

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	/*
	** Parse term: factor {("*"|"/") factor}
	*/
    public int term()
    {
		//To be completed
    }

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	/*
	** Parse factor: ident | number | "(" expression ")" | funcCall | InputStat
	*/

    public int factor()
    {
		//To be completed
    }

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	/*
	** Parse InputStat: "InputNum" "(" ")"
	** I assume that the way that you know you have to execute this method is through parsing factor. So I assume that token "InputNum"
	** has already been detected and here you are going to check for "(" and ")". Then you read a number from the input_values file and
	** you will return the number as the value of the function!
	*/

	public int InputNum()
	{
		int temp = my_scanner.GetSym();

		if (temp != 50)
			Error("\"(\" is missing after InputNum!");

		temp = my_scanner.GetSym();

		if (temp != 35)
			Error("\")\" is missing after InputNum(");

		return input_list.nextInt();

	}

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	/*
	** Parse "OutputNum" "(" expression ")"
	** I assume that "OutputNum" is detected and then this method is called.
	*/

	public void OutputNum()
	{
		int temp = my_scanner.GetSym();

		if (temp != 50)
			Error("\"(\" is missing after OutputNum.");

		int value = expression();

		temp = my_scanner.GetSym();

		if (temp != 35)
			Error("\")\" is missing after OutputNum(expression");

		output.print(value);
		output.print("\t");

		return;
	}


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	/*
	** Parse "OutputNewLine" "(" ")"
	** I assume that "OutputNewLine" is detected and then this method is called.
	*/

	public void OutputNewLine()
	{
		int temp = my_scanner.GetSym();

		if (temp != 50)
			Error("\"(\" is missing after OutputNewLine.");

		temp = my_scanner.GetSym();

		if (temp != 35)
			Error("\")\" is missing after OutputNewLine(");

		output.print("\n");

		return;
	}

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	/* A call to this method should generate the error message, generate the necessary information (line number, etc) and then
	** halt the program execution!
	*/

	private void Error (String errMsg)
	{
		//To be completed
	}

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}//End of public class parser