From 8465a2d918af15c6ca7e07427cea9025144e5649 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 13:26:29 -0700
Subject: [PATCH 01/11] Remove old stopping code.

---
 .../org/nwapw/abacus/fx/AbacusController.java | 86 ++++---------------
 .../nwapw/abacus/plugin/StandardPlugin.java   | 78 +++--------------
 .../org/nwapw/abacus/tree/BinaryNode.java     |  7 +-
 .../org/nwapw/abacus/tree/FunctionNode.java   |  9 +-
 .../java/org/nwapw/abacus/tree/UnaryNode.java |  7 +-
 src/main/resources/abacus.fxml                |  2 -
 6 files changed, 33 insertions(+), 156 deletions(-)

diff --git a/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index 85846a4..91e4fc5 100644
--- a/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -1,6 +1,5 @@
 package org.nwapw.abacus.fx;
 
-import javafx.application.Platform;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
 import javafx.fxml.FXML;
@@ -97,20 +96,6 @@ public class AbacusController implements PluginListener {
      * The abacus instance used for changing the plugin configuration.
      */
     private Abacus abacus;
-    /**
-     * Thread used for calculating.
-     */
-    private Thread calcThread;
-
-    /**
-     * Checks whether the calculator is calculating.
-     */
-    private boolean calculating;
-
-    /**
-     * Seconds delayed for timer;
-     */
-    private double delay = 0;
 
     /**
      * Boolean which represents whether changes were made to the configuration.
@@ -187,63 +172,24 @@ public class AbacusController implements PluginListener {
 
     @FXML
     private void performCalculation() {
-        Runnable calculator = new Runnable() {
-            public void run() {
-                if (delay > 0) {
-                    Runnable timer = new Runnable() {
-                        public void run() {
-                            long gap = (long) (delay * 1000);
-                            long startTime = System.currentTimeMillis();
-                            while (System.currentTimeMillis() - startTime <= gap) {
-                            }
-                            stopCalculation();
-                        }
-                    };
-                    Thread maxTime = new Thread(timer);
-                    maxTime.setName("maxTime");
-                    maxTime.start();
-                }
-                calculating = true;
-                Platform.runLater(() -> inputButton.setDisable(true));
-                TreeNode constructedTree = abacus.parseString(inputField.getText());
-                if (constructedTree == null) {
-                    Platform.runLater(() -> outputText.setText(ERR_SYNTAX));
-                    Platform.runLater(() -> inputButton.setDisable(false));
-                    //return;
-                } else {
-                    NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
-                    if (evaluatedNumber == null) {
-                        if (Thread.currentThread().isInterrupted()) {
-                            Platform.runLater(() -> outputText.setText(ERR_STOP));
-                            Platform.runLater(() -> inputButton.setDisable(false));
-                        } else {
-                            Platform.runLater(() -> outputText.setText(ERR_EVAL));
-                            Platform.runLater(() -> inputButton.setDisable(false));
-                            //return;
-                        }
-                    } else {
-                        Platform.runLater(() -> outputText.setText(evaluatedNumber.toString()));
-                        historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
-
-                        Platform.runLater(() -> inputButton.setDisable(false));
-                        Platform.runLater(() -> inputField.setText(""));
-                    }
-                }
-                calculating = false;
-            }
-        };
-        if (!calculating) {
-            calcThread = new Thread(calculator);
-            calcThread.setName("calcThread");
-            calcThread.start();
+        inputButton.setDisable(true);
+        TreeNode constructedTree = abacus.parseString(inputField.getText());
+        if (constructedTree == null) {
+            outputText.setText(ERR_SYNTAX);
+            inputButton.setDisable(false);
+            return;
         }
-    }
+        NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
+        if (evaluatedNumber == null) {
+            outputText.setText(ERR_EVAL);
+            inputButton.setDisable(false);
+            return;
+        }
+        outputText.setText(evaluatedNumber.toString());
+        historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
 
-    @FXML
-    private void stopCalculation() {
-        calcThread.interrupt();
-        calculating = false;
-        //Platform.runLater(() ->inputButton.setDisable(false));
+        inputButton.setDisable(false);
+        inputField.setText("");
     }
 
     @FXML
diff --git a/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java b/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
index e82ca2e..95b33ec 100755
--- a/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
+++ b/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
@@ -29,13 +29,9 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface sum = params[0];
             for (int i = 1; i < params.length; i++) {
                 sum = sum.add(params[i]);
-                if (Thread.currentThread().isInterrupted())
-                    return null;
             }
             return sum;
         }
@@ -51,8 +47,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].subtract(params[1]);
 
         }
@@ -68,8 +62,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].negate();
         }
     });
@@ -84,13 +76,9 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface product = params[0];
             for (int i = 1; i < params.length; i++) {
                 product = product.multiply(params[i]);
-                if (Thread.currentThread().isInterrupted())
-                    return null;
             }
             return product;
         }
@@ -106,8 +94,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].divide(params[1]);
         }
     });
@@ -125,19 +111,15 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             if (params[0].signum() == 0) {
                 return (new NaiveNumber(1)).promoteTo(params[0].getClass());
             }
             NumberInterface factorial = params[0];
             NumberInterface multiplier = params[0];
             //It is necessary to later prevent calls of factorial on anything but non-negative integers.
-            while (!Thread.currentThread().isInterrupted() && (multiplier = multiplier.subtract(NaiveNumber.ONE.promoteTo(multiplier.getClass()))) != null && multiplier.signum() == 1) {
+            while ((multiplier = multiplier.subtract(NaiveNumber.ONE.promoteTo(multiplier.getClass()))).signum() == 1) {
                 factorial = factorial.multiply(multiplier);
             }
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return factorial;
                 /*if(!storedList.containsKey(params[0].getClass())){
                     storedList.put(params[0].getClass(), new ArrayList<NumberInterface>());
@@ -157,8 +139,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].multiply((new NaiveNumber(params[0].signum())).promoteTo(params[0].getClass()));
         }
     };
@@ -173,32 +153,26 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface param = params[0];
             int powersOf2 = 0;
-            NumberInterface check;
-            while (!Thread.currentThread().isInterrupted() && (check = FUNCTION_ABS.apply(param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())))) != null && (check.compareTo((new NaiveNumber(0.1)).promoteTo(param.getClass()))) >= 0) {
-                if ((check = param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))) != null && check.signum() == 1) {
+            while (FUNCTION_ABS.apply(param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))).compareTo(new NaiveNumber(0.1).promoteTo(param.getClass())) >= 0) {
+                if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() == 1) {
                     param = param.divide(new NaiveNumber(2).promoteTo(param.getClass()));
                     powersOf2++;
-                    if ((check = param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))) == null || check.signum() != 1) {
+                    if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != 1) {
                         break;
                         //No infinite loop for you.
                     }
                 } else {
                     param = param.multiply(new NaiveNumber(2).promoteTo(param.getClass()));
                     powersOf2--;
-                    if ((check = param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))) == null || check.signum() != 1) {
+                    if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != 1) {
                         break;
                         //No infinite loop for you.
                     }
                 }
             }
-            NumberInterface check2;
-            if (!Thread.currentThread().isInterrupted() && (check = getLog2(param)) != null && (check = check.multiply((new NaiveNumber(powersOf2).promoteTo(param.getClass())))) != null && (check2 = getLogPartialSum(param)) != null && (check = check.add(check2)) != null)
-                return check;
-            return null;
+            return getLog2(param).multiply((new NaiveNumber(powersOf2)).promoteTo(param.getClass())).add(getLogPartialSum(param));
         }
 
         /**
@@ -209,22 +183,16 @@ public class StandardPlugin extends Plugin {
          */
         private NumberInterface getLogPartialSum(NumberInterface x) {
 
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface maxError = getMaxError(x);
             x = x.subtract(NaiveNumber.ONE.promoteTo(x.getClass())); //Terms used are for log(x+1).
             NumberInterface currentNumerator = x, currentTerm = x, sum = x;
             int n = 1;
-            NumberInterface check;
-            while (!Thread.currentThread().isInterrupted() && (check = FUNCTION_ABS.apply(currentTerm)) != null && check.compareTo(maxError) > 0) {
+            while (FUNCTION_ABS.apply(currentTerm).compareTo(maxError) > 0) {
                 n++;
-                if ((currentNumerator = currentNumerator.multiply(x)) == null || (currentNumerator = currentNumerator.negate()) == null)
-                    return null;
+                currentNumerator = currentNumerator.multiply(x).negate();
                 currentTerm = currentNumerator.divide(new NaiveNumber(n).promoteTo(x.getClass()));
                 sum = sum.add(currentTerm);
             }
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return sum;
         }
 
@@ -234,8 +202,6 @@ public class StandardPlugin extends Plugin {
          * @return the value of log(2) with the appropriate precision.
          */
         private NumberInterface getLog2(NumberInterface number) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface maxError = getMaxError(number);
             //NumberInterface errorBound = (new NaiveNumber(1)).promoteTo(number.getClass());
             //We'll use the series \sigma_{n >= 1) ((1/3^n + 1/4^n) * 1/n)
@@ -244,17 +210,13 @@ public class StandardPlugin extends Plugin {
             NumberInterface a = (new NaiveNumber(1)).promoteTo(number.getClass()), b = a, c = a;
             NumberInterface sum = NaiveNumber.ZERO.promoteTo(number.getClass());
             int n = 0;
-            while (!Thread.currentThread().isInterrupted() && a.compareTo(maxError) >= 1) {
+            while (a.compareTo(maxError) >= 1) {
                 n++;
                 a = a.divide((new NaiveNumber(3)).promoteTo(number.getClass()));
                 b = b.divide((new NaiveNumber(4)).promoteTo(number.getClass()));
                 c = NaiveNumber.ONE.promoteTo(number.getClass()).divide((new NaiveNumber(n)).promoteTo(number.getClass()));
-                NumberInterface check;
-                if (a == null || (check = a.add(b)) == null || (check = check.multiply(c)) == null || (sum = sum.add(check)) == null)
-                    return null;
+                sum = sum.add(a.add(b).multiply(c));
             }
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return sum;
         }
     };
@@ -378,15 +340,11 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted()) return null;
-            else if (params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
+            if (params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
                 return NaiveNumber.ZERO.promoteTo(params[0].getClass());
             else if (params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
                 return NaiveNumber.ONE.promoteTo(params[1].getClass());
-            FUNCTION_EXP.apply(FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0])).multiply(params[1]));
-            NumberInterface check = FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0]));
-            if(check == null) return null;
-            return FUNCTION_EXP.apply(check.multiply(params[1]));
+            return FUNCTION_EXP.apply(FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0])).multiply(params[1]));
         }
     });
     /**
@@ -524,8 +482,6 @@ public class StandardPlugin extends Plugin {
      * @return a number of numClass with value n factorial.
      */
     public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         if (!FACTORIAL_LISTS.containsKey(numberClass)) {
             FACTORIAL_LISTS.put(numberClass, new ArrayList<>());
             FACTORIAL_LISTS.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
@@ -533,12 +489,10 @@ public class StandardPlugin extends Plugin {
         }
         ArrayList<NumberInterface> list = FACTORIAL_LISTS.get(numberClass);
         if (n >= list.size()) {
-            while (!Thread.currentThread().isInterrupted() && list.size() < n + 16) {
+            while (list.size() < n + 16) {
                 list.add(list.get(list.size() - 1).multiply(new NaiveNumber(list.size()).promoteTo(numberClass)));
             }
         }
-        if (Thread.currentThread().isInterrupted())
-            return null;
         return list.get(n);
     }
 
@@ -578,8 +532,6 @@ public class StandardPlugin extends Plugin {
     }
 
     public static NumberInterface intPow(NumberInterface number, Class<? extends NumberInterface> numberClass, NumberInterface exponent) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         if (exponent.compareTo((new NaiveNumber(0)).promoteTo(numberClass)) == 0) {
             return (new NaiveNumber(1)).promoteTo(numberClass);
         }
@@ -588,14 +540,10 @@ public class StandardPlugin extends Plugin {
         NumberInterface power = number;
         for (NumberInterface currentExponent = (new NaiveNumber(1)).promoteTo(numberClass); currentExponent.compareTo(exponent) < 0; currentExponent = currentExponent.add((new NaiveNumber(1)).promoteTo(numberClass))) {
             power = power.multiply(number);
-            if (Thread.currentThread().isInterrupted())
-                return null;
         }
         if (takeReciprocal) {
             power = (new NaiveNumber(1)).promoteTo(numberClass).divide(power);
         }
-        if (Thread.currentThread().isInterrupted())
-            return null;
         return power;
     }
 
diff --git a/src/main/java/org/nwapw/abacus/tree/BinaryNode.java b/src/main/java/org/nwapw/abacus/tree/BinaryNode.java
index 0ae6acf..6ec7b80 100644
--- a/src/main/java/org/nwapw/abacus/tree/BinaryNode.java
+++ b/src/main/java/org/nwapw/abacus/tree/BinaryNode.java
@@ -92,15 +92,10 @@ public class BinaryNode extends TreeNode {
 
     @Override
     public <T> T reduce(Reducer<T> reducer) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         T leftReduce = left.reduce(reducer);
         T rightReduce = right.reduce(reducer);
         if (leftReduce == null || rightReduce == null) return null;
-        T a = reducer.reduceNode(this, leftReduce, rightReduce);
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        return a;
+        return reducer.reduceNode(this, leftReduce, rightReduce);
     }
 
     @Override
diff --git a/src/main/java/org/nwapw/abacus/tree/FunctionNode.java b/src/main/java/org/nwapw/abacus/tree/FunctionNode.java
index 0f939c8..a0ee26e 100644
--- a/src/main/java/org/nwapw/abacus/tree/FunctionNode.java
+++ b/src/main/java/org/nwapw/abacus/tree/FunctionNode.java
@@ -62,17 +62,12 @@ public class FunctionNode extends TreeNode {
 
     @Override
     public <T> T reduce(Reducer<T> reducer) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         Object[] reducedChildren = new Object[children.size()];
         for (int i = 0; i < reducedChildren.length; i++) {
             reducedChildren[i] = children.get(i).reduce(reducer);
-            if (Thread.currentThread().isInterrupted() || reducedChildren[i] == null) return null;
+            if (reducedChildren[i] == null) return null;
         }
-        T a = reducer.reduceNode(this, reducedChildren);
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        return a;
+        return reducer.reduceNode(this, reducedChildren);
     }
 
     @Override
diff --git a/src/main/java/org/nwapw/abacus/tree/UnaryNode.java b/src/main/java/org/nwapw/abacus/tree/UnaryNode.java
index 7956169..298d25d 100644
--- a/src/main/java/org/nwapw/abacus/tree/UnaryNode.java
+++ b/src/main/java/org/nwapw/abacus/tree/UnaryNode.java
@@ -33,14 +33,9 @@ public class UnaryNode extends TreeNode {
 
     @Override
     public <T> T reduce(Reducer<T> reducer) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         Object reducedChild = applyTo.reduce(reducer);
         if (reducedChild == null) return null;
-        T a = reducer.reduceNode(this, reducedChild);
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        return a;
+        return reducer.reduceNode(this, reducedChild);
     }
 
     /**
diff --git a/src/main/resources/abacus.fxml b/src/main/resources/abacus.fxml
index 11ae276..d3f3cc6 100644
--- a/src/main/resources/abacus.fxml
+++ b/src/main/resources/abacus.fxml
@@ -34,8 +34,6 @@
                             <TextField fx:id="inputField" onAction="#performCalculation"/>
                             <Button fx:id="inputButton" text="Calculate" maxWidth="Infinity"
                                     onAction="#performCalculation"/>
-                            <Button fx:id="stopButton" text="Stop" maxWidth="Infinity"
-                                    onAction="#stopCalculation"/>
                         </VBox>
                     </bottom>
                 </BorderPane>

From 37a759288ab3eb5a2891a1e2cb950d1d8052f9d3 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 13:54:06 -0700
Subject: [PATCH 02/11] Convert NumberInterface into abstract class, and check
 for interruption.

---
 .../ComputationInterruptedException.java      |  9 ++
 .../org/nwapw/abacus/number/NaiveNumber.java  | 22 ++---
 .../nwapw/abacus/number/NumberInterface.java  | 88 +++++++++++++++----
 .../nwapw/abacus/number/PreciseNumber.java    | 22 ++---
 4 files changed, 104 insertions(+), 37 deletions(-)
 create mode 100644 src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java

diff --git a/src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java b/src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java
new file mode 100644
index 0000000..e6537e9
--- /dev/null
+++ b/src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java
@@ -0,0 +1,9 @@
+package org.nwapw.abacus.number;
+
+public class ComputationInterruptedException extends RuntimeException {
+
+    public ComputationInterruptedException(){
+        super("Computation interrupted by user.");
+    }
+
+}
diff --git a/src/main/java/org/nwapw/abacus/number/NaiveNumber.java b/src/main/java/org/nwapw/abacus/number/NaiveNumber.java
index 2f97497..48beb1a 100755
--- a/src/main/java/org/nwapw/abacus/number/NaiveNumber.java
+++ b/src/main/java/org/nwapw/abacus/number/NaiveNumber.java
@@ -3,7 +3,7 @@ package org.nwapw.abacus.number;
 /**
  * An implementation of NumberInterface using a double.
  */
-public class NaiveNumber implements NumberInterface {
+public class NaiveNumber extends NumberInterface {
 
     /**
      * The number zero.
@@ -42,32 +42,32 @@ public class NaiveNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface multiply(NumberInterface multiplier) {
+    public NumberInterface multiplyInternal(NumberInterface multiplier) {
         return new NaiveNumber(value * ((NaiveNumber) multiplier).value);
     }
 
     @Override
-    public NumberInterface divide(NumberInterface divisor) {
+    public NumberInterface divideInternal(NumberInterface divisor) {
         return new NaiveNumber(value / ((NaiveNumber) divisor).value);
     }
 
     @Override
-    public NumberInterface add(NumberInterface summand) {
+    public NumberInterface addInternal(NumberInterface summand) {
         return new NaiveNumber(value + ((NaiveNumber) summand).value);
     }
 
     @Override
-    public NumberInterface subtract(NumberInterface subtrahend) {
+    public NumberInterface subtractInternal(NumberInterface subtrahend) {
         return new NaiveNumber(value - ((NaiveNumber) subtrahend).value);
     }
 
     @Override
-    public NumberInterface negate() {
+    public NumberInterface negateInternal() {
         return new NaiveNumber(-value);
     }
 
     @Override
-    public NumberInterface intPow(int exponent) {
+    public NumberInterface intPowInternal(int exponent) {
         if (exponent == 0) {
             return NaiveNumber.ONE;
         }
@@ -95,17 +95,17 @@ public class NaiveNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface ceiling() {
+    public NumberInterface ceilingInternal() {
         return new NaiveNumber(Math.ceil(value));
     }
 
     @Override
-    public NumberInterface floor() {
+    public NumberInterface floorInternal() {
         return new NaiveNumber(Math.floor(value));
     }
 
     @Override
-    public NumberInterface fractionalPart() {
+    public NumberInterface fractionalPartInternal() {
         return new NaiveNumber(value - Math.floor(value));
     }
 
@@ -115,7 +115,7 @@ public class NaiveNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
+    public NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
         if (toClass == this.getClass()) return this;
         else if (toClass == PreciseNumber.class) {
             return new PreciseNumber(Double.toString(value));
diff --git a/src/main/java/org/nwapw/abacus/number/NumberInterface.java b/src/main/java/org/nwapw/abacus/number/NumberInterface.java
index e8ca571..d79997f 100755
--- a/src/main/java/org/nwapw/abacus/number/NumberInterface.java
+++ b/src/main/java/org/nwapw/abacus/number/NumberInterface.java
@@ -3,14 +3,22 @@ package org.nwapw.abacus.number;
 /**
  * An interface used to represent a number.
  */
-public interface NumberInterface {
+public abstract class NumberInterface {
 
+    /**
+     * Check if the thread was interrupted and
+     * throw an exception to end the computation.
+     */
+    private static void checkInterrupted(){
+        if(Thread.currentThread().isInterrupted())
+            throw new ComputationInterruptedException();
+    }
     /**
      * The maximum precision to which this number operates.
      *
      * @return the precision.
      */
-    int getMaxPrecision();
+    public abstract int getMaxPrecision();
 
     /**
      * Multiplies this number by another, returning
@@ -19,7 +27,12 @@ public interface NumberInterface {
      * @param multiplier the multiplier
      * @return the result of the multiplication.
      */
-    NumberInterface multiply(NumberInterface multiplier);
+    protected abstract NumberInterface multiplyInternal(NumberInterface multiplier);
+
+    public final NumberInterface multiply(NumberInterface multiplier){
+        checkInterrupted();
+        return multiplyInternal(multiplier);
+    }
 
     /**
      * Divides this number by another, returning
@@ -28,7 +41,12 @@ public interface NumberInterface {
      * @param divisor the divisor
      * @return the result of the division.
      */
-    NumberInterface divide(NumberInterface divisor);
+    protected abstract NumberInterface divideInternal(NumberInterface divisor);
+
+    public final NumberInterface divide(NumberInterface divisor){
+        checkInterrupted();
+        return divideInternal(divisor);
+    }
 
     /**
      * Adds this number to another, returning
@@ -37,7 +55,12 @@ public interface NumberInterface {
      * @param summand the summand
      * @return the result of the summation.
      */
-    NumberInterface add(NumberInterface summand);
+    protected abstract NumberInterface addInternal(NumberInterface summand);
+
+    public final NumberInterface add(NumberInterface summand){
+        checkInterrupted();
+        return addInternal(summand);
+    }
 
     /**
      * Subtracts another number from this number,
@@ -46,7 +69,12 @@ public interface NumberInterface {
      * @param subtrahend the subtrahend.
      * @return the result of the subtraction.
      */
-    NumberInterface subtract(NumberInterface subtrahend);
+    protected abstract NumberInterface subtractInternal(NumberInterface subtrahend);
+
+    public final NumberInterface subtract(NumberInterface subtrahend){
+        checkInterrupted();
+        return subtractInternal(subtrahend);
+    }
 
     /**
      * Returns a new instance of this number with
@@ -54,7 +82,12 @@ public interface NumberInterface {
      *
      * @return the new instance.
      */
-    NumberInterface negate();
+    protected abstract NumberInterface negateInternal();
+
+    public final NumberInterface negate(){
+        checkInterrupted();
+        return negateInternal();
+    }
 
     /**
      * Raises this number to an integer power.
@@ -62,7 +95,12 @@ public interface NumberInterface {
      * @param exponent the exponent to which to take the number.
      * @return the resulting value.
      */
-    NumberInterface intPow(int exponent);
+    protected abstract NumberInterface intPowInternal(int exponent);
+
+    public final NumberInterface intPow(int exponent){
+        checkInterrupted();
+        return intPowInternal(exponent);
+    }
 
     /**
      * Compares this number to another.
@@ -70,35 +108,50 @@ public interface NumberInterface {
      * @param number the number to compare to.
      * @return same as Integer.compare();
      */
-    int compareTo(NumberInterface number);
+    public abstract int compareTo(NumberInterface number);
 
     /**
      * Same as Math.signum().
      *
      * @return 1 if this number is positive, -1 if this number is negative, 0 if this number is 0.
      */
-    int signum();
+    public abstract int signum();
 
     /**
      * Returns the least integer greater than or equal to the number.
      *
      * @return the least integer >= the number, if int can hold the value.
      */
-    NumberInterface ceiling();
+    protected abstract NumberInterface ceilingInternal();
+
+    public final NumberInterface ceiling(){
+        checkInterrupted();
+        return ceilingInternal();
+    }
 
     /**
      * Return the greatest integer less than or equal to the number.
      *
      * @return the greatest int >= the number, if int can hold the value.
      */
-    NumberInterface floor();
+    protected abstract NumberInterface floorInternal();
+
+    public final NumberInterface floor(){
+        checkInterrupted();
+        return floorInternal();
+    }
 
     /**
      * Returns the fractional part of the number.
      *
      * @return the fractional part of the number.
      */
-    NumberInterface fractionalPart();
+    protected abstract NumberInterface fractionalPartInternal();
+
+    public final NumberInterface fractionalPart(){
+        checkInterrupted();
+        return fractionalPartInternal();
+    }
 
     /**
      * Returns the integer representation of this number, discarding any fractional part,
@@ -106,7 +159,7 @@ public interface NumberInterface {
      *
      * @return
      */
-    int intValue();
+    public abstract int intValue();
 
     /**
      * Promotes this class to another number class.
@@ -114,6 +167,11 @@ public interface NumberInterface {
      * @param toClass the class to promote to.
      * @return the resulting new instance.
      */
-    NumberInterface promoteTo(Class<? extends NumberInterface> toClass);
+    protected abstract NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass);
+
+    public final NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
+        checkInterrupted();
+        return promoteToInternal(toClass);
+    }
 
 }
diff --git a/src/main/java/org/nwapw/abacus/number/PreciseNumber.java b/src/main/java/org/nwapw/abacus/number/PreciseNumber.java
index 1baa867..abc657f 100755
--- a/src/main/java/org/nwapw/abacus/number/PreciseNumber.java
+++ b/src/main/java/org/nwapw/abacus/number/PreciseNumber.java
@@ -7,7 +7,7 @@ import java.math.RoundingMode;
  * A number that uses a BigDecimal to store its value,
  * leading to infinite possible precision.
  */
-public class PreciseNumber implements NumberInterface {
+public class PreciseNumber extends NumberInterface {
 
     /**
      * The number one.
@@ -52,27 +52,27 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface multiply(NumberInterface multiplier) {
+    public NumberInterface multiplyInternal(NumberInterface multiplier) {
         return new PreciseNumber(this.value.multiply(((PreciseNumber) multiplier).value));
     }
 
     @Override
-    public NumberInterface divide(NumberInterface divisor) {
+    public NumberInterface divideInternal(NumberInterface divisor) {
         return new PreciseNumber(value.divide(((PreciseNumber) divisor).value, this.getMaxPrecision(), RoundingMode.HALF_UP));
     }
 
     @Override
-    public NumberInterface add(NumberInterface summand) {
+    public NumberInterface addInternal(NumberInterface summand) {
         return new PreciseNumber(value.add(((PreciseNumber) summand).value));
     }
 
     @Override
-    public NumberInterface subtract(NumberInterface subtrahend) {
+    public NumberInterface subtractInternal(NumberInterface subtrahend) {
         return new PreciseNumber(value.subtract(((PreciseNumber) subtrahend).value));
     }
 
     @Override
-    public NumberInterface intPow(int exponent) {
+    public NumberInterface intPowInternal(int exponent) {
         if (exponent == 0) {
             return PreciseNumber.ONE;
         }
@@ -99,7 +99,7 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface ceiling() {
+    public NumberInterface ceilingInternal() {
         String str = value.toPlainString();
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
@@ -109,7 +109,7 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface floor() {
+    public NumberInterface floorInternal() {
         String str = value.toPlainString();
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
@@ -119,7 +119,7 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface fractionalPart() {
+    public NumberInterface fractionalPartInternal() {
         String str = value.toPlainString();
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
@@ -134,12 +134,12 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface negate() {
+    public NumberInterface negateInternal() {
         return new PreciseNumber(value.negate());
     }
 
     @Override
-    public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
+    public NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
         if (toClass == this.getClass()) {
             return this;
         }

From 4f7fe053dede32f9da0368dcfd956650d275f79d Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 13:57:27 -0700
Subject: [PATCH 03/11] Add a stop button.

---
 src/main/java/org/nwapw/abacus/fx/AbacusController.java | 8 +++++++-
 src/main/resources/abacus.fxml                          | 2 ++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index 91e4fc5..e328912 100644
--- a/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -70,6 +70,8 @@ public class AbacusController implements PluginListener {
     @FXML
     private Button inputButton;
     @FXML
+    private Button stopButton;
+    @FXML
     private ComboBox<String> numberImplementationBox;
     @FXML
     private ListView<ToggleablePlugin> enabledPluginView;
@@ -86,7 +88,6 @@ public class AbacusController implements PluginListener {
     private ObservableList<String> numberImplementationOptions;
 
     /**
-     * <<<<<<< HEAD
      * The list of plugin objects that can be toggled on and off,
      * and, when reloaded, get added to the plugin manager's black list.
      */
@@ -192,6 +193,11 @@ public class AbacusController implements PluginListener {
         inputField.setText("");
     }
 
+    @FXML
+    private void performStop(){
+        System.out.println("Stopping");
+    }
+
     @FXML
     private void performSaveAndReload() {
         performSave();
diff --git a/src/main/resources/abacus.fxml b/src/main/resources/abacus.fxml
index d3f3cc6..9ee57d4 100644
--- a/src/main/resources/abacus.fxml
+++ b/src/main/resources/abacus.fxml
@@ -34,6 +34,8 @@
                             <TextField fx:id="inputField" onAction="#performCalculation"/>
                             <Button fx:id="inputButton" text="Calculate" maxWidth="Infinity"
                                     onAction="#performCalculation"/>
+                            <Button fx:id="stopButton" text="Stop" maxWidth="Infinity"
+                                    onAction="#performStop"/>
                         </VBox>
                     </bottom>
                 </BorderPane>

From 4bd52e514c61c1ae32efee7c8972324dea787b26 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 14:34:31 -0700
Subject: [PATCH 04/11] Run calculations via thread, and stop thread if
 necessary.

---
 .../org/nwapw/abacus/fx/AbacusController.java | 58 +++++++++++++------
 src/main/resources/abacus.fxml                |  2 +-
 2 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index e328912..3ea5656 100644
--- a/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -1,5 +1,6 @@
 package org.nwapw.abacus.fx;
 
+import javafx.application.Platform;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
 import javafx.fxml.FXML;
@@ -10,6 +11,7 @@ import javafx.util.Callback;
 import javafx.util.StringConverter;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.config.Configuration;
+import org.nwapw.abacus.number.ComputationInterruptedException;
 import org.nwapw.abacus.number.NumberInterface;
 import org.nwapw.abacus.plugin.PluginListener;
 import org.nwapw.abacus.plugin.PluginManager;
@@ -110,6 +112,39 @@ public class AbacusController implements PluginListener {
      * The alert shown when a press to "apply" is needed.
      */
     private Alert reloadAlert;
+    /**
+     * The runnable used to perform the calculation.
+     */
+    private final Runnable CALCULATION_RUNNABLE = new Runnable() {
+
+        private String attemptCalculation(){
+            TreeNode constructedTree = abacus.parseString(inputField.getText());
+            if (constructedTree == null) {
+                return ERR_SYNTAX;
+            }
+            try {
+                NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
+                if (evaluatedNumber == null) {
+                    return ERR_EVAL;
+                }
+                historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
+            } catch (ComputationInterruptedException exception) {
+                return ERR_STOP;
+            }
+            return "";
+        }
+
+        @Override
+        public void run() {
+            String calculation = attemptCalculation();
+            Platform.runLater(() -> {
+                outputText.setText(calculation);
+                inputButton.setDisable(false);
+                stopButton.setDisable(true);
+            });
+        }
+    };
+    private Thread calculationThread;
 
     /**
      * Alerts the user if the changes they made
@@ -174,28 +209,15 @@ public class AbacusController implements PluginListener {
     @FXML
     private void performCalculation() {
         inputButton.setDisable(true);
-        TreeNode constructedTree = abacus.parseString(inputField.getText());
-        if (constructedTree == null) {
-            outputText.setText(ERR_SYNTAX);
-            inputButton.setDisable(false);
-            return;
-        }
-        NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
-        if (evaluatedNumber == null) {
-            outputText.setText(ERR_EVAL);
-            inputButton.setDisable(false);
-            return;
-        }
-        outputText.setText(evaluatedNumber.toString());
-        historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
-
-        inputButton.setDisable(false);
-        inputField.setText("");
+        stopButton.setDisable(false);
+        calculationThread = new Thread(CALCULATION_RUNNABLE);
+        calculationThread.start();
     }
 
     @FXML
     private void performStop(){
-        System.out.println("Stopping");
+        if(calculationThread != null)
+            calculationThread.interrupt();
     }
 
     @FXML
diff --git a/src/main/resources/abacus.fxml b/src/main/resources/abacus.fxml
index 9ee57d4..495c654 100644
--- a/src/main/resources/abacus.fxml
+++ b/src/main/resources/abacus.fxml
@@ -35,7 +35,7 @@
                             <Button fx:id="inputButton" text="Calculate" maxWidth="Infinity"
                                     onAction="#performCalculation"/>
                             <Button fx:id="stopButton" text="Stop" maxWidth="Infinity"
-                                    onAction="#performStop"/>
+                                    onAction="#performStop" disable="true"/>
                         </VBox>
                     </bottom>
                 </BorderPane>

From a7ed7b48cf989be5e42a71f0540ad45f9f11bd85 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 14:34:57 -0700
Subject: [PATCH 05/11] Re-introduce arthur326's fix for ln speed.

---
 src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java b/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
index 95b33ec..c123caa 100755
--- a/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
+++ b/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
@@ -166,7 +166,7 @@ public class StandardPlugin extends Plugin {
                 } else {
                     param = param.multiply(new NaiveNumber(2).promoteTo(param.getClass()));
                     powersOf2--;
-                    if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != 1) {
+                    if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != -1) {
                         break;
                         //No infinite loop for you.
                     }

From a5a1f3a96a5985d9d067794fa9ca3760aa259cd0 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 14:36:42 -0700
Subject: [PATCH 06/11] Fix clearing input field.

---
 src/main/java/org/nwapw/abacus/fx/AbacusController.java | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index 3ea5656..a3ebe22 100644
--- a/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -139,6 +139,7 @@ public class AbacusController implements PluginListener {
             String calculation = attemptCalculation();
             Platform.runLater(() -> {
                 outputText.setText(calculation);
+                inputField.setText("");
                 inputButton.setDisable(false);
                 stopButton.setDisable(true);
             });

From 90a0fa2dc73ffce64827981f9773a77a7261fea3 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 14:43:24 -0700
Subject: [PATCH 07/11] Set output string correctly.

---
 src/main/java/org/nwapw/abacus/fx/AbacusController.java | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index a3ebe22..5eb0275 100644
--- a/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -127,11 +127,12 @@ public class AbacusController implements PluginListener {
                 if (evaluatedNumber == null) {
                     return ERR_EVAL;
                 }
-                historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
+                String resultingString = evaluatedNumber.toString();
+                historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), resultingString));
+                return resultingString;
             } catch (ComputationInterruptedException exception) {
                 return ERR_STOP;
             }
-            return "";
         }
 
         @Override

From 2381c93fb57c16fdd596be6016e6bd55ad0cc89d Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 15:19:39 -0700
Subject: [PATCH 08/11] Add new comments.

---
 .../org/nwapw/abacus/fx/AbacusController.java |  3 +
 .../ComputationInterruptedException.java      |  7 ++
 .../nwapw/abacus/number/NumberInterface.java  | 81 +++++++++++++++++++
 3 files changed, 91 insertions(+)

diff --git a/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index 5eb0275..459508c 100644
--- a/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -146,6 +146,9 @@ public class AbacusController implements PluginListener {
             });
         }
     };
+    /**
+     * The thread in which the computation runs.
+     */
     private Thread calculationThread;
 
     /**
diff --git a/src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java b/src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java
index e6537e9..cc3e9e1 100644
--- a/src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java
+++ b/src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java
@@ -1,7 +1,14 @@
 package org.nwapw.abacus.number;
 
+/**
+ * Exception thrown when the computation is interrupted by
+ * the user.
+ */
 public class ComputationInterruptedException extends RuntimeException {
 
+    /**
+     * Creates a new exception of this type.
+     */
     public ComputationInterruptedException(){
         super("Computation interrupted by user.");
     }
diff --git a/src/main/java/org/nwapw/abacus/number/NumberInterface.java b/src/main/java/org/nwapw/abacus/number/NumberInterface.java
index d79997f..306f8d7 100755
--- a/src/main/java/org/nwapw/abacus/number/NumberInterface.java
+++ b/src/main/java/org/nwapw/abacus/number/NumberInterface.java
@@ -29,6 +29,15 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface multiplyInternal(NumberInterface multiplier);
 
+    /**
+     * Multiplies this number by another, returning
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param multiplier the multiplier
+     * @return the result of the multiplication.
+     */
     public final NumberInterface multiply(NumberInterface multiplier){
         checkInterrupted();
         return multiplyInternal(multiplier);
@@ -43,6 +52,15 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface divideInternal(NumberInterface divisor);
 
+    /**
+     * Divides this number by another, returning
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param divisor the divisor
+     * @return the result of the division.
+     */
     public final NumberInterface divide(NumberInterface divisor){
         checkInterrupted();
         return divideInternal(divisor);
@@ -57,6 +75,15 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface addInternal(NumberInterface summand);
 
+    /**
+     * Adds this number to another, returning
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param summand the summand
+     * @return the result of the summation.
+     */
     public final NumberInterface add(NumberInterface summand){
         checkInterrupted();
         return addInternal(summand);
@@ -71,6 +98,15 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface subtractInternal(NumberInterface subtrahend);
 
+    /**
+     * Subtracts another number from this number,
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param subtrahend the subtrahend.
+     * @return the result of the subtraction.
+     */
     public final NumberInterface subtract(NumberInterface subtrahend){
         checkInterrupted();
         return subtractInternal(subtrahend);
@@ -84,6 +120,15 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface negateInternal();
 
+
+    /**
+     * Returns a new instance of this number with
+     * the sign flipped. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @return the new instance.
+     */
     public final NumberInterface negate(){
         checkInterrupted();
         return negateInternal();
@@ -97,6 +142,14 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface intPowInternal(int exponent);
 
+    /**
+     * Raises this number to an integer power. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param exponent the exponent to which to take the number.
+     * @return the resulting value.
+     */
     public final NumberInterface intPow(int exponent){
         checkInterrupted();
         return intPowInternal(exponent);
@@ -124,6 +177,13 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface ceilingInternal();
 
+    /**
+     * Returns the least integer greater than or equal to the number.
+     * Also, checks if the thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @return the least integer >= the number, if int can hold the value.
+     */
     public final NumberInterface ceiling(){
         checkInterrupted();
         return ceilingInternal();
@@ -136,6 +196,13 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface floorInternal();
 
+    /**
+     * Return the greatest integer less than or equal to the number.
+     * Also, checks if the thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @return the greatest int >= the number, if int can hold the value.
+     */
     public final NumberInterface floor(){
         checkInterrupted();
         return floorInternal();
@@ -148,6 +215,12 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface fractionalPartInternal();
 
+    /**
+     * Returns the fractional part of the number.
+     * Also, checks if the thread has been interrupted,
+     * and if so, throws an exception.
+     * @return the fractional part of the number.
+     */
     public final NumberInterface fractionalPart(){
         checkInterrupted();
         return fractionalPartInternal();
@@ -169,6 +242,14 @@ public abstract class NumberInterface {
      */
     protected abstract NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass);
 
+    /**
+     * Promotes this class to another number class. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param toClass the class to promote to.
+     * @return the resulting new instance.
+     */
     public final NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
         checkInterrupted();
         return promoteToInternal(toClass);

From 55257f72747ebfe5e09a2ac3cf69614dfd42fbbe Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 15:58:43 -0700
Subject: [PATCH 09/11] Fix exception handling.

---
 .../org/nwapw/abacus/fx/AbacusController.java     | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index 459508c..d514237 100644
--- a/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -51,6 +51,10 @@ public class AbacusController implements PluginListener {
      * Constant string that is displayed if the calculations are stopped before they are done.
      */
     private static final String ERR_STOP = "Stopped";
+    /**
+     * Constant string that is displayed if the calculations are interrupted by an exception.
+     */
+    private static final String ERR_EXCEPTION = "Exception Thrown";
     @FXML
     private TabPane coreTabPane;
     @FXML
@@ -118,11 +122,11 @@ public class AbacusController implements PluginListener {
     private final Runnable CALCULATION_RUNNABLE = new Runnable() {
 
         private String attemptCalculation(){
-            TreeNode constructedTree = abacus.parseString(inputField.getText());
-            if (constructedTree == null) {
-                return ERR_SYNTAX;
-            }
             try {
+                TreeNode constructedTree = abacus.parseString(inputField.getText());
+                if (constructedTree == null) {
+                    return ERR_SYNTAX;
+                }
                 NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
                 if (evaluatedNumber == null) {
                     return ERR_EVAL;
@@ -132,6 +136,9 @@ public class AbacusController implements PluginListener {
                 return resultingString;
             } catch (ComputationInterruptedException exception) {
                 return ERR_STOP;
+            } catch (RuntimeException exception){
+                exception.printStackTrace();
+                return ERR_EXCEPTION;
             }
         }
 

From 48e6e658d0e6272c11d8125bba8c8d1a3337ad42 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 15:59:49 -0700
Subject: [PATCH 10/11] Fix mismatched parentheses causing exceptions.

---
 src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java b/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
index 6239ed9..e6e930d 100644
--- a/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
+++ b/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
@@ -162,6 +162,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
     @Override
     public TreeNode constructTree(List<Match<TokenType>> tokens) {
         tokens = intoPostfix(new ArrayList<>(tokens));
+        if(tokens == null) return null;
         Collections.reverse(tokens);
         return constructRecursive(tokens);
     }

From b1b8af014dd943cf204f9d111ffcf6f36d4084ae Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 5 Aug 2017 16:01:08 -0700
Subject: [PATCH 11/11] Prevent leaving unparsed tokens ignored, throwing error
 instead.

---
 src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java b/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
index e6e930d..5d35032 100644
--- a/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
+++ b/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
@@ -164,7 +164,8 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
         tokens = intoPostfix(new ArrayList<>(tokens));
         if(tokens == null) return null;
         Collections.reverse(tokens);
-        return constructRecursive(tokens);
+        TreeNode constructedTree = constructRecursive(tokens);
+        return tokens.size() == 0 ? constructedTree : null;
     }
 
     @Override