Qt Reference Documentation

# calculator.js Example File

script/calculator/calculator.js

     Function.prototype.bind = function() {
         var func = this;
         var thisObject = arguments[0];
         var args = Array.prototype.slice.call(arguments, 1);
         return function() {
             return func.apply(thisObject, args);
         }
     }

     function Calculator(ui)
     {
         this.ui = ui;

         this.pendingAdditiveOperator = Calculator.NO_OPERATOR;
         this.pendingMultiplicativeOperator = Calculator.NO_OPERATOR;
         this.sumInMemory = 0;
         this.sumSoFar = 0;
         this.factorSoFar = 0;
         this.waitingForOperand = true;

         with (ui) {
             display.text = "0";

             zeroButton.clicked.connect(this.digitClicked.bind(this, 0));
             oneButton.clicked.connect(this.digitClicked.bind(this, 1));
             twoButton.clicked.connect(this.digitClicked.bind(this, 2));
             threeButton.clicked.connect(this.digitClicked.bind(this, 3));
             fourButton.clicked.connect(this.digitClicked.bind(this, 4));
             fiveButton.clicked.connect(this.digitClicked.bind(this, 5));
             sixButton.clicked.connect(this.digitClicked.bind(this, 6));
             sevenButton.clicked.connect(this.digitClicked.bind(this, 7));
             eightButton.clicked.connect(this.digitClicked.bind(this, 8));
             nineButton.clicked.connect(this.digitClicked.bind(this, 9));

             pointButton.clicked.connect(this, "pointClicked");
             changeSignButton.clicked.connect(this, "changeSignClicked");

             backspaceButton.clicked.connect(this, "backspaceClicked");
             clearButton.clicked.connect(this, "clear");
             clearAllButton.clicked.connect(this, "clearAll");

             clearMemoryButton.clicked.connect(this, "clearMemory");
             readMemoryButton.clicked.connect(this, "readMemory");
             setMemoryButton.clicked.connect(this, "setMemory");
             addToMemoryButton.clicked.connect(this, "addToMemory");

             divisionButton.clicked.connect(this.multiplicativeOperatorClicked.bind(this, Calculator.DIVISION_OPERATOR));
             timesButton.clicked.connect(this.multiplicativeOperatorClicked.bind(this, Calculator.TIMES_OPERATOR));
             minusButton.clicked.connect(this.additiveOperatorClicked.bind(this, Calculator.MINUS_OPERATOR));
             plusButton.clicked.connect(this.additiveOperatorClicked.bind(this, Calculator.PLUS_OPERATOR));

             squareRootButton.clicked.connect(this.unaryOperatorClicked.bind(this, Calculator.SQUARE_OPERATOR));
             powerButton.clicked.connect(this.unaryOperatorClicked.bind(this, Calculator.POWER_OPERATOR));
             reciprocalButton.clicked.connect(this.unaryOperatorClicked.bind(this, Calculator.RECIPROCAL_OPERATOR));
             equalButton.clicked.connect(this, "equalClicked");
         }
     }

     Calculator.NO_OPERATOR = 0;
     Calculator.SQUARE_OPERATOR = 1;
     Calculator.POWER_OPERATOR = 2;
     Calculator.RECIPROCAL_OPERATOR = 3;
     Calculator.DIVISION_OPERATOR = 4;
     Calculator.TIMES_OPERATOR = 5;
     Calculator.MINUS_OPERATOR = 6;
     Calculator.PLUS_OPERATOR = 7;

     Calculator.prototype.abortOperation = function()
     {
         this.clearAll();
         this.ui.display.text = "####";
     }

     Calculator.prototype.calculate = function(rightOperand, pendingOperator)
     {
         if (pendingOperator == Calculator.PLUS_OPERATOR) {
             this.sumSoFar += rightOperand;
         } else if (pendingOperator == Calculator.MINUS_OPERATOR) {
             this.sumSoFar -= rightOperand;
         } else if (pendingOperator == Calculator.TIMES_OPERATOR) {
             this.factorSoFar *= rightOperand;
         } else if (pendingOperator == Calculator.DIVISION_OPERATOR) {
             if (rightOperand == 0)
                 return false;
             this.factorSoFar /= rightOperand;
         }
         return true;
     }

     Calculator.prototype.digitClicked = function(digitValue)
     {
         if ((digitValue == 0) && (this.ui.display.text == "0"))
             return;
         if (this.waitingForOperand) {
             this.ui.display.clear();
             this.waitingForOperand = false;
         }
         this.ui.display.text += digitValue;
     }

     Calculator.prototype.unaryOperatorClicked = function(op)
     {
         var operand = this.ui.display.text - 0;
         var result = 0;
         if (op == Calculator.SQUARE_OPERATOR) {
             if (operand < 0) {
                 this.abortOperation();
                 return;
             }
             result = Math.sqrt(operand);
         } else if (op == Calculator.POWER_OPERATOR) {
             result = Math.pow(operand, 2);
         } else if (op == Calculator.RECIPROCAL_OPERATOR) {
             if (operand == 0.0) {
                 this.abortOperation();
                 return;
             }
             result = 1 / operand;
         }
         this.ui.display.text = result + "";
         this.waitingForOperand = true;
     }

     Calculator.prototype.additiveOperatorClicked = function(op)
     {
         var operand = this.ui.display.text - 0;

         if (this.pendingMultiplicativeOperator != Calculator.NO_OPERATOR) {
             if (!this.calculate(operand, this.pendingMultiplicativeOperator)) {
                 this.abortOperation();
                 return;
             }
             this.ui.display.text = this.factorSoFar + "";
             operand = this.factorSoFar;
             this.factorSoFar = 0;
             this.pendingMultiplicativeOperator = Calculator.NO_OPERATOR;
         }

         if (this.pendingAdditiveOperator != Calculator.NO_OPERATOR) {
             if (!this.calculate(operand, this.pendingAdditiveOperator)) {
                 this.abortOperation();
                 return;
             }
             this.ui.display.text = this.sumSoFar + "";
         } else {
             this.sumSoFar = operand;
         }

         this.pendingAdditiveOperator = op;
         this.waitingForOperand = true;
     }

     Calculator.prototype.multiplicativeOperatorClicked = function(op)
     {
         var operand = this.ui.display.text - 0;

         if (this.pendingMultiplicativeOperator != Calculator.NO_OPERATOR) {
             if (!this.calculate(operand, this.pendingMultiplicativeOperator)) {
                 this.abortOperation();
                 return;
             }
             this.ui.display.text = this.factorSoFar + "";
         } else {
             this.factorSoFar = operand;
         }

         this.pendingMultiplicativeOperator = op;
         this.waitingForOperand = true;
     }

     Calculator.prototype.equalClicked = function()
     {
         var operand = this.ui.display.text - 0;

         if (this.pendingMultiplicativeOperator != Calculator.NO_OPERATOR) {
             if (!this.calculate(operand, this.pendingMultiplicativeOperator)) {
                 this.abortOperation();
                 return;
             }
             operand = this.factorSoFar;
             this.factorSoFar = 0.0;
             this.pendingMultiplicativeOperator = Calculator.NO_OPERATOR;
         }
         if (this.pendingAdditiveOperator != Calculator.NO_OPERATOR) {
             if (!this.calculate(operand, this.pendingAdditiveOperator)) {
                 this.abortOperation();
                 return;
             }
             this.pendingAdditiveOperator = Calculator.NO_OPERATOR;
         } else {
             this.sumSoFar = operand;
         }

         this.ui.display.text = this.sumSoFar + "";
         this.sumSoFar = 0.0;
         this.waitingForOperand = true;
     }

     Calculator.prototype.pointClicked = function()
     {
         if (this.waitingForOperand)
             this.ui.display.text = "0";
         if (this.ui.display.text.indexOf(".") == -1)
             this.ui.display.text += ".";
         this.waitingForOperand = false;
     }

     Calculator.prototype.changeSignClicked = function()
     {
         var text = this.ui.display.text;
         var value = text - 0;

         if (value > 0) {
             text = "-" + text;
         } else if (value < 0) {
             text = text.slice(1);
         }
         this.ui.display.text = text;
     }

     Calculator.prototype.backspaceClicked = function()
     {
         if (this.waitingForOperand)
             return;

         var text = this.ui.display.text;
         text = text.slice(0, -1);
         if (text.length == 0) {
             text = "0";
             this.waitingForOperand = true;
         }
         this.ui.display.text = text;
     }

     Calculator.prototype.clear = function()
     {
         if (this.waitingForOperand)
             return;

         this.ui.display.text = "0";
         this.waitingForOperand = true;
     }

     Calculator.prototype.clearAll = function()
     {
         this.sumSoFar = 0.0;
         this.factorSoFar = 0.0;
         this.pendingAdditiveOperator = Calculator.NO_OPERATOR;
         this.pendingMultiplicativeOperator = Calculator.NO_OPERATOR;
         this.ui.display.text = "0";
         this.waitingForOperand = true;
     }

     Calculator.prototype.clearMemory = function()
     {
         this.sumInMemory = 0.0;
     }

     Calculator.prototype.readMemory = function()
     {
         this.ui.display.text = this.sumInMemory + "";
         this.waitingForOperand = true;
     }

     Calculator.prototype.setMemory = function()
     {
         this.equalClicked();
         this.sumInMemory = this.ui.display.text - 0;
     }

     Calculator.prototype.addToMemory = function()
     {
         this.equalClicked();
         this.sumInMemory += this.ui.display.text - 0;
     }