Visual Basic - PASAR CODIGO JAVA A VISUAL BASIC

// Exception class for parser errors.

class ParserException extends Exception {

  String errStr; // describes the error 

  public ParserException(String str) {

    errStr = str;

  }

  public String toString() {

    return errStr;

  }

}

class Parser {

  // These are the token types. 

  final int NONE = 0;

  final int DELIMITER = 1;

  final int VARIABLE = 2;

  final int NUMBER = 3;

  //CODIGO NUEVO

  final int FUNCION = 4;

  final int CONSTANTE = 5;

  // These are the types of syntax errors. 

  final int SYNTAX = 0;

  final int UNBALPARENS = 1;

  final int NOEXP = 2;

  final int DIVBYZERO = 3;

   // This token indicates end-of-expression. 

  final String EOE = "\0";

  private String exp;   // refers to expression string  

  private int expIdx;   // current index into the expression  

  private String token; // holds current token  

  private int tokType;  // holds token's type  

  // Array for variables.  

  private double vars[] = new double[26];

  // Parser entry point.  

  public double evaluate(String expstr) throws ParserException

  {

    double result;

    exp = expstr;

    expIdx = 0;

    getToken();

    if(token.equals(EOE))

      handleErr(NOEXP); // no expression present  

    // Parse and evaluate the expression. 

    result = evalExp1();

    if(!token.equals(EOE)) // last token must be EOE  

      handleErr(SYNTAX);

    return result;

  }

  // Process an assignment.  

  private double evalExp1() throws ParserException

  {

    double result;

    int varIdx;

    int ttokType;

    String temptoken;

    if(tokType == VARIABLE) {

      // save old token  

      temptoken = new String(token);

      ttokType = tokType;

      // Compute the index of the variable.  

      varIdx = Character.toUpperCase(token.charAt(0)) - 'A';  

      getToken();

      if(!token.equals("=")) {

        putBack(); // return current token  

        // restore old token -- not an assignment  

        token = new String(temptoken);

        tokType = ttokType;

      }

      else {

        getToken(); // get next part of exp  

        result = evalExp2();

        vars[varIdx] = result;

        return result;

      }

    }

    return evalExp2();

  }

  // Add or subtract two terms.  

  private double evalExp2() throws ParserException

  {

    char op;

    double result;

    double partialResult;

    result = evalExp3();

    while((op = token.charAt(0)) == '+' || op == '-') {  

      getToken();

      partialResult = evalExp3();

      switch(op) {

        case '-':  

          result = result - partialResult;

          break;

        case '+':  

          result = result + partialResult;

          break;

      }

    }

    return result;

  }

  	 // Add or subtract two terms.  

  private double evalExp3() throws ParserException

  {

    char op;

    double result;

    double partialResult;

    result = evalExp4();

    while((op = token.charAt(0)) == '*' ||  

           op == '/' || op == '%') {  

      getToken();

      partialResult = evalExp4();

      switch(op) {

        case '*':  

          result = result * partialResult;

          break;

        case '/':  

          if(partialResult == 0.0)

            handleErr(DIVBYZERO);

          result = result / partialResult;

          break;

        case '%':  

          if(partialResult == 0.0)

            handleErr(DIVBYZERO);

          result = result % partialResult;

          break;

      }

    }

    if(result == 0){

		result = Math.abs(result);

		}

    return result;

  }

  // Process an exponent.  

  private double evalExp4() throws ParserException

  {

    double result;

    double partialResult;

    double ex;

    int t;

    result = evalExp5();

    if(token.equals("^")) {

      getToken();

      partialResult = evalExp4();

      ex = result;

      if(partialResult == 0.0) {

        result = 1.0;

      } else

        for(t=(int)partialResult-1; t > 0; t--)

          result = result * ex;

    }

    return result;

  }

  // Evaluate a unary + or -.  

  private double evalExp5() throws ParserException

  {

    double result;

    String  op;

    op = "";

    if((tokType == DELIMITER) &&

        token.equals("+") || token.equals("-")) {

      op = token;

      getToken();

    }

    result = evalExp8();

    if(op.equals("-")) result = -result;

    return result;

  }

  // lee el menos 

  private double evalExp8() throws ParserException

  {

    double result;

    if(token.equals("(")) {

      getToken();

      result = evalExp2();

      if(!token.equals(")"))

        handleErr(UNBALPARENS);

      getToken();

    }

    else result = atom();

    return result;

  }

  // Get the value of a number or variable.  

  private double atom() throws ParserException

  {

    double result = 0.0;

    switch(tokType) {

      case NUMBER:

        try {

          result = Double.parseDouble(token);

        } catch (NumberFormatException exc) {

          handleErr(SYNTAX);

        }

        getToken();

        break;

        case CONSTANTE:

       	if( token.equals("pi")|| token.equals("PI") ){

       	result = Math.PI;

       	}

       	if(token.equals("E") || token.equals("e")){

       	result = Math.E;

       	}

      	getToken();

       //System.out.println(result);

      	break;

      case VARIABLE:

        result = findVar(token);

        getToken();

        break;

      default:

       handleErr(SYNTAX);

        break;

    }

    return result;

  }

   // Return the value of a variable.  

  private double findVar(String vname) throws ParserException

  {

    if(!Character.isLetter(vname.charAt(0))){

      handleErr(SYNTAX);

      return 0.0;

    }

    return vars[Character.toUpperCase(vname.charAt(0))-'A'];  

  }

  // Return a token to the input stream.  

  private void putBack()

  {

    if(token == EOE) return;

    for(int i=0; i < token.length(); i++) expIdx--;

  }

  // Handle an error.  

  private void handleErr(int error) throws ParserException

  {

    String[] err = {

      "Syntax Error",

      "Unbalanced Parentheses",

      "No Expression Present",

      "Division by Zero",

    };

    throw new ParserException(err[error]);

  }

  // Obtain the next token.  

  private void getToken()

  {

    tokType = NONE;

    token = "";

    // Check for end of expression.  

    if(expIdx == exp.length()) {

      token = EOE;

      return;

    }

    // Skip over white space. 

    while(expIdx < exp.length() &&

      Character.isWhitespace(exp.charAt(expIdx))) ++expIdx;

    // Trailing whitespace ends expression. 

    if(expIdx == exp.length()) {

      token = EOE;

      return;

    }

    if(isDelim(exp.charAt(expIdx))) { // is operator  

      token += exp.charAt(expIdx);

      expIdx++;

      tokType = DELIMITER;

    }

    else if(Character.isLetter(exp.charAt(expIdx))) { // is variable  

      while(!isDelim(exp.charAt(expIdx))) {

        token += exp.charAt(expIdx);

        expIdx++;

        if(expIdx >= exp.length()) break;

      }

      	if(isfuncion(token)){

      		tokType=FUNCION;

      		System.out.println("Estoy en Funcion");

      	}else if(isconstante(token)){

      		tokType=CONSTANTE;

      		System.out.print("Estoy en Constantes");

      	}else

      tokType = VARIABLE;

      	}

    else if(Character.isDigit(exp.charAt(expIdx))) { // is number  

      while(!isDelim(exp.charAt(expIdx))) {

        token += exp.charAt(expIdx);

        expIdx++;

        if(expIdx >= exp.length()) break;

      }

      tokType = NUMBER;

    }

  }

  // Return true if c is a delimiter.

  private boolean isDelim(char c)

  {

    if((" +-/*%^=()".indexOf(c) != -1))

      return true;

    return false;

  }

//Lee las Funciones

  private boolean isfuncion(String s)

  {

    if(( "cos tan sin sqrt".indexOf(s) != -1))

      return true;

    return false;

  }

//Lee las Constantes

   private boolean isconstante(String a)

  {

    if(("pi PI E e".indexOf(a) != -1))

      return true;

    return false;

  }

}

Imports System

' Exception class for parser errors.

Friend Class ParserException

	Inherits Exception

  Friend errStr As String ' describes the error

  Public Sub New(ByVal str As String)

	errStr = str

  End Sub

  Public Overrides Function ToString() As String

	Return errStr

  End Function

End Class

Friend Class Parser

  ' These are the token types. 

  Friend ReadOnly NONE As Integer = 0

  Friend ReadOnly DELIMITER As Integer = 1

  Friend ReadOnly VARIABLE As Integer = 2

  Friend ReadOnly NUMBER As Integer = 3

  'CODIGO NUEVO

  Friend ReadOnly FUNCION As Integer = 4

  Friend ReadOnly CONSTANTE As Integer = 5

  ' These are the types of syntax errors. 

  Friend ReadOnly SYNTAX As Integer = 0

  Friend ReadOnly UNBALPARENS As Integer = 1

  Friend ReadOnly NOEXP As Integer = 2

  Friend ReadOnly DIVBYZERO As Integer = 3

   ' This token indicates end-of-expression. 

  Friend ReadOnly EOE As String = ChrW(&O0).ToString()

  Private exp As String ' refers to expression string

  Private expIdx As Integer ' current index into the expression

  Private token As String ' holds current token

  Private tokType As Integer ' holds token's type

  ' Array for variables.  

  Private vars(25) As Double

  ' Parser entry point.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: public double evaluate(String expstr) throws ParserException

  Public Overridable Function evaluate(ByVal expstr As String) As Double

	Dim result As Double

	exp = expstr

	expIdx = 0

	Token

	If token.Equals(EOE) Then

	  handleErr(NOEXP) ' no expression present

	End If

	' Parse and evaluate the expression. 

	result = evalExp1()

	If Not token.Equals(EOE) Then ' last token must be EOE

	  handleErr(SYNTAX)

	End If

	Return result

  End Function

  ' Process an assignment.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double evalExp1() throws ParserException

  Private Function evalExp1() As Double

	Dim result As Double

	Dim varIdx As Integer

	Dim ttokType As Integer

	Dim temptoken As String

	If tokType = VARIABLE Then

	  ' save old token  

	  temptoken = token

	  ttokType = tokType

	  ' Compute the index of the variable.  

	  varIdx = Char.ToUpper(token.Chars(0)) - AscW("A"c)

	  Token

	  If Not token.Equals("=") Then

		putBack() ' return current token

		' restore old token -- not an assignment  

		token = temptoken

		tokType = ttokType

	  Else

		Token ' get next part of exp

		result = evalExp2()

		vars(varIdx) = result

		Return result

	  End If

	End If

	Return evalExp2()

  End Function

  ' Add or subtract two terms.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double evalExp2() throws ParserException

  Private Function evalExp2() As Double

	Dim op As Char

	Dim result As Double

	Dim partialResult As Double

	result = evalExp3()

'JAVA TO VB CONVERTER WARNING: An assignment within expression was extracted from the following statement:

'ORIGINAL LINE: while((op = token.charAt(0)) == "+"c || op == "-"c)

	op = token.Chars(0)

	Do While op = "+"c OrElse op = "-"c

	  Token

	  partialResult = evalExp3()

	  Select Case op

		Case "-"c

		  result = result - partialResult

		Case "+"c

		  result = result + partialResult

	  End Select

		op = token.Chars(0)

	Loop

	Return result

  End Function

	   ' Add or subtract two terms.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double evalExp3() throws ParserException

  Private Function evalExp3() As Double

	Dim op As Char

	Dim result As Double

	Dim partialResult As Double

	result = evalExp4()

'JAVA TO VB CONVERTER WARNING: An assignment within expression was extracted from the following statement:

'ORIGINAL LINE: while((op = token.charAt(0)) == "*"c || op == "/"c || op == "%"c)

	op = token.Chars(0)

	Do While op = "*"c OrElse op = "/"c OrElse op = "%"c

	  Token

	  partialResult = evalExp4()

	  Select Case op

		Case "*"c

		  result = result * partialResult

		Case "/"c

		  If partialResult = 0.0 Then

			handleErr(DIVBYZERO)

		  End If

		  result = result / partialResult

		Case "%"c

		  If partialResult = 0.0 Then

			handleErr(DIVBYZERO)

		  End If

		  result = result Mod partialResult

	  End Select

		op = token.Chars(0)

	Loop

	If result = 0 Then

		result = Math.Abs(result)

	End If

	Return result

  End Function

  ' Process an exponent.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double evalExp4() throws ParserException

  Private Function evalExp4() As Double

	Dim result As Double

	Dim partialResult As Double

	Dim ex As Double

	Dim t As Integer

	result = evalExp5()

	If token.Equals("^") Then

	  Token

	  partialResult = evalExp4()

	  ex = result

	  If partialResult = 0.0 Then

		result = 1.0

	  Else

		For t = CInt(Math.Truncate(partialResult))-1 To 1 Step -1

		  result = result * ex

		Next t

	  End If

	End If

	Return result

  End Function

  ' Evaluate a unary + or -.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double evalExp5() throws ParserException

  Private Function evalExp5() As Double

	Dim result As Double

	Dim op As String

	op = ""

	If (tokType = DELIMITER) AndAlso token.Equals("+") OrElse token.Equals("-") Then

	  op = token

	  Token

	End If

	result = evalExp8()

	If op.Equals("-") Then

		result = -result

	End If

	Return result

  End Function

  ' lee el menos 

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double evalExp8() throws ParserException

  Private Function evalExp8() As Double

	Dim result As Double

	If token.Equals("(") Then

	  Token

	  result = evalExp2()

	  If Not token.Equals(")") Then

		handleErr(UNBALPARENS)

	  End If

	  Token

	Else

		result = atom()

	End If

	Return result

  End Function

  ' Get the value of a number or variable.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double atom() throws ParserException

  Private Function atom() As Double

	Dim result As Double = 0.0

	Select Case tokType

	  Case NUMBER

		Try

		  result = Convert.ToDouble(token)

		Catch exc As NumberFormatException

		  handleErr(SYNTAX)

		End Try

		Token

		Case CONSTANTE

		   If token.Equals("pi") OrElse token.Equals("PI") Then

		   result = Math.PI

		   End If

		   If token.Equals("E") OrElse token.Equals("e") Then

		   result = Math.E

		   End If

		  Token

	   'System.out.println(result);

	  Case VARIABLE

		result = findVar(token)

		Token

	  Case Else

	   handleErr(SYNTAX)

	End Select

	Return result

  End Function

   ' Return the value of a variable.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private double findVar(String vname) throws ParserException

  Private Function findVar(ByVal vname As String) As Double

	If Not Char.IsLetter(vname.Chars(0)) Then

	  handleErr(SYNTAX)

	  Return 0.0

	End If

	Return vars(Char.ToUpper(vname.Chars(0))-AscW("A"c))

  End Function

  ' Return a token to the input stream.  

  Private Sub putBack()

	If token = EOE Then

		Return

	End If

	For i As Integer = 0 To token.Length - 1

		expIdx -= 1

	Next i

  End Sub

  ' Handle an error.  

'JAVA TO VB CONVERTER WARNING: Method 'throws' clauses are not available in .NET:

'ORIGINAL LINE: private void handleErr(int error) throws ParserException

  Private Sub handleErr(ByVal [error] As Integer)

	Dim err() As String = { "Syntax Error", "Unbalanced Parentheses", "No Expression Present", "Division by Zero"}

	Throw New ParserException(err([error]))

  End Sub

  ' Obtain the next token.  

  Private Sub getToken()

	tokType = NONE

	token = ""

	' Check for end of expression.  

	If expIdx = exp.Length Then

	  token = EOE

	  Return

	End If

	' Skip over white space. 

	Do While expIdx < exp.Length AndAlso Char.IsWhiteSpace(exp.Chars(expIdx))

		expIdx += 1

	Loop

	' Trailing whitespace ends expression. 

	If expIdx = exp.Length Then

	  token = EOE

	  Return

	End If

	If isDelim(exp.Chars(expIdx)) Then ' is operator

	  token &= exp.Chars(expIdx)

	  expIdx += 1

	  tokType = DELIMITER

	ElseIf Char.IsLetter(exp.Chars(expIdx)) Then ' is variable

	  Do While Not isDelim(exp.Chars(expIdx))

		token &= exp.Chars(expIdx)

		expIdx += 1

		If expIdx >= exp.Length Then

			Exit Do

		End If

	  Loop

		  If isfuncion(token) Then

			  tokType=FUNCION

			  Console.WriteLine("Estoy en Funcion")

		  ElseIf isconstante(token) Then

			  tokType=CONSTANTE

			  Console.Write("Estoy en Constantes")

		  Else

	  tokType = VARIABLE

		  End If

	ElseIf Char.IsDigit(exp.Chars(expIdx)) Then ' is number

	  Do While Not isDelim(exp.Chars(expIdx))

		token &= exp.Chars(expIdx)

		expIdx += 1

		If expIdx >= exp.Length Then

			Exit Do

		End If

	  Loop

	  tokType = NUMBER

	End If

  End Sub

  ' Return true if c is a delimiter.

  Private Function isDelim(ByVal c As Char) As Boolean

	If (" +-/*%^=()".IndexOf(c) <> -1) Then

	  Return True

	End If

	Return False

  End Function

'Lee las Funciones

  Private Function isfuncion(ByVal s As String) As Boolean

	If ("cos tan sin sqrt".IndexOf(s) <> -1) Then

	  Return True

	End If

	Return False

  End Function

'Lee las Constantes

   Private Function isconstante(ByVal a As String) As Boolean

	If ("pi PI E e".IndexOf(a) <> -1) Then

	  Return True

	End If

	Return False

   End Function

End Class