Exemplo n.º 1
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 /**
  * Call this function if you want to parse expressions which involve complex numbers. This method
  * specifies "i" as the imaginary unit (0,1). Two functions re() and im() are also added for
  * extracting the real or imaginary components of a complex number respectively.
  *
  * <p>
  *
  * @since 2.3.0 alpha The functions cmod and arg are added to get the modulus and argument.
  * @since 2.3.0 beta 1 The functions complex and polar to convert x,y and r,theta to Complex.
  * @since Feb 05 added complex conjugate conj.
  */
 public void addComplex() {
   // add constants to Symbol Table
   symTab.addConstant("i", new Complex(0, 1));
   funTab.put("re", new Real());
   funTab.put("im", new Imaginary());
   funTab.put("arg", new Arg());
   funTab.put("cmod", new Abs());
   funTab.put("complex", new ComplexPFMC());
   funTab.put("polar", new Polar());
   funTab.put("conj", new Conjugate());
 }
Exemplo n.º 2
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  /**
   * Visit a variable node. The value of the variable is obtained from the symbol table (symTab) and
   * pushed onto the stack.
   */
  public Object visit(ASTVarNode node, Object data) throws ParseException {

    // try to get the variable object
    Variable var = symTab.getVar(node.getVarName());
    if (var == null) {
      String message = "Could not evaluate " + node.getVarName() + ": ";
      throw new ParseException(message + "the variable was not found in the symbol table");
    }

    // get the variable value
    // Object temp = var.getValue();
    Object temp = var.getValue();

    if (trapNullValues && temp == null) {
      String message = "Could not evaluate " + node.getVarName() + ": ";
      throw new ParseException(message + "variable not set");
    }
    // all is fine
    // push the value on the stack
    stack.push(temp);
    return data;
  }
Exemplo n.º 3
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 /**
  * Gets the object representing the variable with a given name.
  *
  * @param name the name of the variable to find.
  * @return the Variable object or null if name not found.
  * @since 2.3.0 alpha
  */
 public Variable getVar(String name) {
   return symTab.getVar(name);
 }
Exemplo n.º 4
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 /**
  * Sets the value of a variable. The variable must exist beforehand.
  *
  * @param name name of the variable.
  * @param val the initial value of the variable.
  * @throws NullPointerException if the variable has not been previously created with {@link
  *     #addVariable(String,Object)} first.
  * @since 2.3.0 alpha
  * @since April 05 - throws an exception if variable unset.
  */
 public void setVarValue(String name, Object val) {
   symTab.setVarValue(name, val);
 }
Exemplo n.º 5
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 /**
  * Returns the value of the variable with given name.
  *
  * @param name name of the variable.
  * @return the current value of the variable.
  * @since 2.3.0 alpha
  */
 public Object getVarValue(String name) {
   return symTab.getVar(name).getValue();
 }
Exemplo n.º 6
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 /**
  * Removes a variable from the parser. For example after calling addStandardConstants(),
  * removeVariable("e") might be called to remove the euler constant from the set of variables.
  *
  * @return The value of the variable if it was added earlier. If the variable is not in the table
  *     of variables, <code>null</code> is returned.
  */
 public Object removeVariable(String name) {
   return symTab.remove(name);
 }
Exemplo n.º 7
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 /**
  * Adds a new variable to the parser as an object, or updates the value of an existing variable.
  * This must be done before parsing an expression so the parser is aware that the new variable may
  * be contained in the expression.
  *
  * @param name Name of the variable to be added
  * @param object Initial value or new value for the variable
  */
 public void addVariable(String name, Object object) {
   symTab.makeVarIfNeeded(name, object);
 }
Exemplo n.º 8
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 /**
  * Adds a new complex variable to the parser, or updates the value of an existing variable. This
  * must be done before parsing an expression so the parser is aware that the new variable may be
  * contained in the expression.
  *
  * @param name Name of the variable to be added
  * @param re Initial real value or new real value for the variable
  * @param im Initial imaginary value or new imaginary value for the variable
  * @return Complex object of the variable
  */
 public Complex addVariable(String name, double re, double im) {
   Complex object = new Complex(re, im);
   symTab.makeVarIfNeeded(name, object);
   return object;
 }
Exemplo n.º 9
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 /**
  * Adds a new variable to the parser, or updates the value of an existing variable. This must be
  * done before parsing an expression so the parser is aware that the new variable may be contained
  * in the expression.
  *
  * @param name Name of the variable to be added
  * @param value Initial value or new value for the variable
  * @return Double object of the variable
  */
 public Double addVariable(String name, double value) {
   Double object = new Double(value);
   symTab.makeVarIfNeeded(name, object);
   return object;
 }
Exemplo n.º 10
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 /**
  * Adds a constant. This is a variable whose value cannot be changed.
  *
  * @since 2.3.0 beta 1
  */
 public void addConstant(String name, Object value) {
   symTab.addConstant(name, value);
 }
Exemplo n.º 11
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 /**
  * Adds the constants pi and e to the parser. As addStandardFunctions(), this method should be
  * called immediately after the JEP object is created.
  */
 public void addStandardConstants() {
   // add constants to Symbol Table
   symTab.addConstant("pi", new Double(Math.PI));
   symTab.addConstant("e", new Double(Math.E));
 }