Calculator App for ChromeOS with fixes for templates/CSS to support this application.

samples/calculator/tape.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class Tape {
+  static final int OP_NOOP = 0;

[Jacob, 2012/04/05 18:06:01]

looks like these could be const not final. same for other *enums*

+  static final int OP_PLUS = 1;
+  static final int OP_MINUS = 2;
+  static final int OP_MULTI = 3;
+  static final int OP_DIV = 4;
+  static final int OP_EQUAL = 5;
+  static final int OP_CLEAR = 6;
+
+  Tape() {
+    clearTape();
+  }
+
+  void addToTape(int op, String number) {
+    double displayTotal;
+    double numberAsValue;
+
+    if (number != "." && number != "-" && number != "-.") {
+      try {
+        numberAsValue = Math.parseDouble(number.length == 0 ? "0" : number);
+      } catch (final BadNumberFormatException e) {
+        displayError(e.toString());
+        return;
+      }
+    } else {
+      // Display just the .
+      displayTotal = total;
+      numberAsValue = 0.0;
+    }
+
+    String opAsStr;
+
+    if (op != OP_NOOP || currentOperator == null) {
+      // Compute the real running total user pressed a mathematical operator.
+      switch (currentOperator) {
+        case OP_NOOP:
+          total = numberAsValue;
+          break;
+        case OP_PLUS:
+          total += numberAsValue;
+          break;
+        case OP_MINUS:
+          total -= numberAsValue;
+          break;
+        case OP_MULTI:
+          total *= numberAsValue;
+          break;
+        case OP_DIV:
+          total /= numberAsValue;

[Jacob, 2012/04/05 18:06:01]

do you want to do anything to avoid div by 0.?

+          break;
+        case OP_EQUAL:
+          // Do nothing total is final total.
+          if (number.length == 0) return;
+          break;
+        default:
+          total = numberAsValue;
+      }
+    } else if (op == OP_NOOP && currentOperator == OP_EQUAL) {
+      // If no operator after = pressed we're starting from scratch.
+      total = numberAsValue;
+    }
+
+    // Compute if the op (key pressed) it's not a mathematical operator but we
+    // want to display the current subtotal if real math operator was pressed.
+    if (op == OP_NOOP) {
+      switch (currentOperator) {
+        case OP_PLUS:
+          displayTotal = total + numberAsValue;
+          break;
+        case OP_MINUS:
+          displayTotal = total - numberAsValue;
+          break;
+        case OP_MULTI:
+          displayTotal = total * numberAsValue;
+          break;
+        case OP_DIV:
+          displayTotal = total / numberAsValue;
+          break;
+        case OP_EQUAL:
+          displayTotal = total;
+          break;
+        default:
+          // nothing to do.
+      }
+    } else {
+      displayTotal = total;
+    }
+
+    // Current operator to display.
+    switch (op) {
+      case OP_NOOP:
+      case OP_EQUAL:
+        opAsStr = "   ";
+        break;
+      case OP_PLUS:
+        opAsStr = "+ ";

[Jacob, 2012/04/05 18:06:01]

perhaps use a the concise Dart syntax for a map literal instead for this case?

+        break;
+      case OP_MINUS:
+        opAsStr = "- ";
+        break;
+      case OP_MULTI:
+        opAsStr = "* ";
+        break;
+      case OP_DIV:
+        opAsStr = "/ ";
+        break;
+    }
+    if (op != OP_NOOP) {
+      currentOperator = op;
+    }
+
+    final element = new Element.tag('div');
+
+    DivElement active = activeInput;

[Jacob, 2012/04/05 18:06:01]

DivElement --> Element here and elsewhere
Casting to DivElement tends to serve no purpose other than to make code fragile.

+    if (op == OP_NOOP) {
+      if (active != null) {
+        String displayedOp = active.elements[0].text;
+        active.innerHTML = tapeUI.firstOp(displayedOp, number);
+      } else {
+        element.innerHTML = tapeUI.displayOpAndNumber(opAsStr, number);
+        tapeUI.tape.elements.add(element.elements[0]);
+        element.innerHTML = tapeUI.alignSubTotal();;
+        tapeUI.tape.elements.add(element.elements[0]);
+        element.innerHTML = tapeUI.lineBreak();
+        tapeUI.tape.elements.add(element.elements[0]);
+      }
+
+      // Update running total if it exist.
+      active = activeTotal;
+      if (active != null) {
+        active.text = "= ${formatOutput(displayTotal)}";
+      }
+    } else {
+      removeActiveElements();
+
+      String leftSide;
+      if (op == OP_EQUAL) {
+        leftSide = tapeUI.displayEqual();
+      } else {
+        leftSide = tapeUI.displayOp(opAsStr);
+      }
+
+      element.innerHTML = leftSide;
+      tapeUI.tape.elements.add(element.elements[0]);
+
+      if (op == OP_EQUAL) {
+        element.innerHTML = tapeUI.displayTotal(formatOutput(displayTotal));
+      } else {
+        element.innerHTML = tapeUI.displayActiveTotal();
+      }
+      tapeUI.tape.elements.add(element.elements[0]);
+
+      element.innerHTML = tapeUI.lineBreak();
+      tapeUI.tape.elements.add(element.elements[0]);
+    }
+
+    scrollToTapeBottom();
+  }
+
+  String formatOutput(double displayTotal) {
+    String formattedNum = "${displayTotal.toStringAsFixed(5)}";
+    int dotIdx = formattedNum.indexOf(".");
+    if (dotIdx >= 0) {
+      if (formattedNum.substring(dotIdx) == ".00000") {
+        formattedNum = formattedNum.substring(0, dotIdx);
+      }
+    }
+
+    return formattedNum;
+  }
+
+  void displayError(String err) {
+    removeActiveElements();
+    DivElement element = new Element.tag("div");
+    element.innerHTML = tapeUI.displayError(err);
+    tapeUI.tape.elements.add(element.elements[0]);
+
+    scrollToTapeBottom();
+
+    currentOperator = null;
+    currentRegister = "";
+    total = 0.0;
+  }
+
+  void scrollToTapeBottom() {
+    tapeUI.tape.rect.then((ElementRect rect) {
+      // theTape.rect.scroll.top = rect.scroll.height;
+      // TODO(terry): Would like to set scrollTop of tape doesn't seem to work
+      //              so I scroll by max lines.
+      tapeUI.tape.scrollByLines(100000);
+    });
+  }
+
+  void removeActiveElements() {
+    final element = new Element.tag('div');
+
+    DivElement active = activeInput;
+    if (active != null) {
+      element.innerHTML = tapeUI.replaceActiveOp(active.innerHTML);
+      active.replaceWith(element.elements[0]);
+
+      active = activeTotal;
+      if (active != null) {
+        element.innerHTML = tapeUI.replaceActiveTotal(active.text);
+        active.replaceWith(element.elements[0]);
+      }
+    }
+  }
+
+  void clearTotal() {
+    final element = new Element.tag('div');
+  
+    element.innerHTML = tapeUI.clearCalculation();
+    tapeUI.tape.elements.add(element.elements[0]);
+  
+    scrollToTapeBottom();
+  }
+
+  bool get isClear() {
+    return tapeUI.tape.elements.last().classes.contains(TapeUI.clearCalc);
+  }
+
+  void clearTape() {
+    tapeUI.tape.elements.clear();
+
+    SettingsDialog settingsUI = new SettingsDialog();
+    tapeUI.tape.elements.add(settingsUI.root);
+    mySettings = new Settings(settingsUI, Settings.THEME_BUTTON);
+  }
+
+  DivElement get activeInput() => window.document.query("#activeInput");

[Jacob, 2012/04/05 18:06:01]

window.document.query --> document.query

or better yet

tapeUI.query if this item is under the tape ui.

+  DivElement get activeTotal() => window.document.query("#activeTotal");
+
+  void clear() {
+    final element = new Element.tag('div');
+    element.innerHTML = tapeUI.clearCalculation();
+    tapeUI.tape.elements.add(element.elements[0]);

[Jacob, 2012/04/05 18:06:01]

i see the pattern of creating a div, setting some inner text and adding it to
the tape elements a lot. add a helper fn for it.

+  }
+}