Implement the negation operator.

src/main/java/org/nwapw/abacus/Abacus.java

@@ -1,6 +1,6 @@
 package org.nwapw.abacus;
 
-import org.nwapw.abacus.config.ConfigurationObject;
+import org.nwapw.abacus.config.Configuration;
 import org.nwapw.abacus.fx.AbacusApplication;
 import org.nwapw.abacus.number.NaiveNumber;
 import org.nwapw.abacus.number.NumberInterface;
@@ -46,7 +46,7 @@ public class Abacus {
     /**
      * The configuration loaded from a file.
      */
-    private ConfigurationObject configuration;
+    private Configuration configuration;
     /**
      * The tree builder used to construct a tree
      * from a string.
@@ -59,8 +59,8 @@ public class Abacus {
     public Abacus() {
         pluginManager = new PluginManager();
         numberReducer = new NumberReducer(this);
-        configuration = new ConfigurationObject(CONFIG_FILE);
-        configuration.save(CONFIG_FILE);
+        configuration = new Configuration(CONFIG_FILE);
+        configuration.saveTo(CONFIG_FILE);
         LexerTokenizer lexerTokenizer = new LexerTokenizer();
         ShuntingYardParser shuntingYardParser = new ShuntingYardParser(this);
         treeBuilder = new TreeBuilder<>(lexerTokenizer, shuntingYardParser);
@@ -114,7 +114,7 @@ public class Abacus {
      *
      * @return the configuration object.
      */
-    public ConfigurationObject getConfiguration() {
+    public Configuration getConfiguration() {
         return configuration;
     }
 

src/main/java/org/nwapw/abacus/config/Configuration.java

@@ -1,14 +1,83 @@
 package org.nwapw.abacus.config;
 
+import com.moandjiezana.toml.Toml;
+import com.moandjiezana.toml.TomlWriter;
+
+import java.io.File;
+import java.io.IOException;
+
 /**
- * Serializable class that will be used to load TOML
- * configurations.
+ * The configuration object that stores
+ * options that the user can change.
  */
 public class Configuration {
 
     /**
-     * The type of number this calculator should use.
+     * The TOML writer used to write this configuration to a file.
      */
-    public String numberType;
+    private static final TomlWriter TOML_WRITER = new TomlWriter();
+    /**
+     * The TOML reader used to load this config from a file.
+     */
+    private static final Toml TOML_READER = new Toml();
 
+    /**
+     * The implementation of the number that should be used.
+     */
+    private String numberImplementation = "naive";
+
+    /**
+     * Creates a new configuration with the given values.
+     * @param numberImplementation the number implementation, like "naive" or "precise"
+     */
+    public Configuration(String numberImplementation){
+        this.numberImplementation = numberImplementation;
+    }
+
+    /**
+     * Loads a configuration from a given file, keeping non-specified fields default.
+     * @param fromFile the file to load from.
+     */
+    public Configuration(File fromFile){
+        if(!fromFile.exists()) return;
+        copyFrom(TOML_READER.read(fromFile).to(Configuration.class));
+    }
+
+    /**
+     * Copies the values from the given configuration into this one.
+     * @param otherConfiguration the configuration to copy from.
+     */
+    public void copyFrom(Configuration otherConfiguration){
+        this.numberImplementation = otherConfiguration.numberImplementation;
+    }
+
+    /**
+     * Saves this configuration to the given file, creating
+     * any directories that do not exist.
+     * @param file the file to save to.
+     */
+    public void saveTo(File file){
+        if(file.getParentFile() != null) file.getParentFile().mkdirs();
+        try {
+            TOML_WRITER.write(this, file);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * Gets the number implementation from this configuration.
+     * @return the number implementation.
+     */
+    public String getNumberImplementation() {
+        return numberImplementation;
+    }
+
+    /**
+     * Sets the number implementation for the configuration
+     * @param numberImplementation the number implementation.
+     */
+    public void setNumberImplementation(String numberImplementation) {
+        this.numberImplementation = numberImplementation;
+    }
 }

src/main/java/org/nwapw/abacus/config/ConfigurationObject.java

@@ -1,111 +0,0 @@
-package org.nwapw.abacus.config;
-
-import com.moandjiezana.toml.Toml;
-import com.moandjiezana.toml.TomlWriter;
-
-import java.io.File;
-import java.io.IOException;
-
-/**
- * A configuration object, which essentially
- * manages saving, loading, and getting values
- * from the configuration. While Configuration is
- * the data model, this is the interface with it.
- */
-public class ConfigurationObject {
-
-    /**
-     * The writer used to store the configuration.
-     */
-    private static final TomlWriter TOML_WRITER = new TomlWriter();
-    /**
-     * The configuration instance being modeled.
-     */
-    private Configuration configuration;
-
-    /**
-     * Creates a new configuration object with the given config.
-     *
-     * @param config the config to use.
-     */
-    public ConfigurationObject(Configuration config) {
-        setup(config);
-    }
-
-    /**
-     * Create a configuration object by attempting to
-     * load a config from the given path, using the
-     * default configuration otherwise.
-     *
-     * @param path the path to attempt to load.
-     */
-    public ConfigurationObject(File path) {
-        Configuration config;
-        if (!path.exists()) {
-            config = getDefaultConfig();
-        } else {
-            Toml parse = new Toml();
-            parse.read(path);
-            config = parse.to(Configuration.class);
-        }
-        setup(config);
-    }
-
-    /**
-     * Creates a new configuration object with the
-     * default configuration.
-     */
-    public ConfigurationObject() {
-        setup(getDefaultConfig());
-    }
-
-    /**
-     * Sets up the ConfigurationObject.
-     * different constructors do different things,
-     * but they all lead here.
-     *
-     * @param configuration the configuration to set up with.
-     */
-    private void setup(Configuration configuration) {
-        this.configuration = configuration;
-    }
-
-    /**
-     * Creates a default configuration.
-     *
-     * @return the newly created default configuration.
-     */
-    private Configuration getDefaultConfig() {
-        configuration = new Configuration();
-        configuration.numberType = "naive";
-        return configuration;
-    }
-
-    /**
-     * Returns the implementation the user has requested to
-     * represent their numbers.
-     *
-     * @return the implementation name.
-     */
-    public String getNumberImplementation() {
-        return configuration.numberType;
-    }
-
-    /**
-     * Saves the ConfigurationObject to the given file.
-     *
-     * @param toFile the file to save ot.
-     * @return true if the save succeed, false if otherwise.
-     */
-    public boolean save(File toFile) {
-        if (toFile.getParentFile() != null) toFile.getParentFile().mkdirs();
-        try {
-            TOML_WRITER.write(configuration, toFile);
-            return true;
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-        return false;
-    }
-
-}

src/main/java/org/nwapw/abacus/function/OperatorType.java

@@ -4,5 +4,5 @@ package org.nwapw.abacus.function;
  * The type of an operator, describing how it should behave.
  */
 public enum OperatorType {
-    BINARY_INFIX, UNARY_POSTFIX
+    BINARY_INFIX, UNARY_POSTFIX, UNARY_PREFIX
 }

src/main/java/org/nwapw/abacus/fx/AbacusController.java

@@ -40,6 +40,8 @@ public class AbacusController {
     private TextField inputField;
     @FXML
     private Button inputButton;
+    @FXML
+    private ComboBox<String> numberImplementationBox;
 
     /**
      * The list of history entries, created by the users.
@@ -50,6 +52,8 @@ public class AbacusController {
      * The abacus instance used for calculations and all
      * other main processing code.
      */
+    private ObservableList<String> numberImplementationOptions;
+
     private Abacus abacus;
 
     @FXML
@@ -57,9 +61,15 @@ public class AbacusController {
         Callback<TableColumn<HistoryModel, String>, TableCell<HistoryModel, String>> cellFactory =
                 param -> new CopyableCell<>();
 
-        abacus = new Abacus();
         historyData = FXCollections.observableArrayList();
         historyTable.setItems(historyData);
+        numberImplementationOptions = FXCollections.observableArrayList();
+        numberImplementationBox.setItems(numberImplementationOptions);
+        numberImplementationBox.valueProperty().addListener((observable, oldValue, newValue)
+                -> {
+            abacus.getConfiguration().setNumberImplementation(newValue);
+            abacus.getConfiguration().saveTo(Abacus.CONFIG_FILE);
+        });
         historyTable.getSelectionModel().setCellSelectionEnabled(true);
         inputColumn.setCellFactory(cellFactory);
         inputColumn.setCellValueFactory(cell -> cell.getValue().inputProperty());
@@ -67,6 +77,12 @@ public class AbacusController {
         parsedColumn.setCellValueFactory(cell -> cell.getValue().parsedProperty());
         outputColumn.setCellFactory(cellFactory);
         outputColumn.setCellValueFactory(cell -> cell.getValue().outputProperty());
+
+        abacus = new Abacus();
+        numberImplementationOptions.addAll(abacus.getPluginManager().getAllNumbers());
+        String actualImplementation = abacus.getConfiguration().getNumberImplementation();
+        String toSelect = (numberImplementationOptions.contains(actualImplementation)) ? actualImplementation : "naive";
+        numberImplementationBox.getSelectionModel().select(toSelect);
     }
 
     @FXML

src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java

@@ -55,9 +55,12 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
     public List<Match<TokenType>> intoPostfix(List<Match<TokenType>> from) {
         ArrayList<Match<TokenType>> output = new ArrayList<>();
         Stack<Match<TokenType>> tokenStack = new Stack<>();
+        TokenType previousType;
+        TokenType matchType = null;
         while (!from.isEmpty()) {
             Match<TokenType> match = from.remove(0);
-            TokenType matchType = match.getType();
+            previousType = matchType;
+            matchType = match.getType();
             if (matchType == TokenType.NUM) {
                 output.add(match);
             } else if (matchType == TokenType.FUNCTION) {
@@ -74,7 +77,13 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                     continue;
                 }
 
-                while (!tokenStack.empty()) {
+                if(tokenString.equals("-") && (previousType == null || previousType == TokenType.OP ||
+                        previousType == TokenType.OPEN_PARENTH)){
+                    from.add(0, new Match<>("`", TokenType.OP));
+                    continue;
+                }
+
+                while (!tokenStack.empty() && type == OperatorType.BINARY_INFIX) {
                     Match<TokenType> otherMatch = tokenStack.peek();
                     TokenType otherMatchType = otherMatch.getType();
                     if (!(otherMatchType == TokenType.OP || otherMatchType == TokenType.FUNCTION)) break;
@@ -103,8 +112,8 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
         }
         while (!tokenStack.empty()) {
             Match<TokenType> match = tokenStack.peek();
-            TokenType matchType = match.getType();
-            if (!(matchType == TokenType.OP || matchType == TokenType.FUNCTION)) return null;
+            TokenType newMatchType = match.getType();
+            if (!(newMatchType == TokenType.OP || newMatchType == TokenType.FUNCTION)) return null;
             output.add(tokenStack.pop());
         }
         return output;
@@ -127,11 +136,11 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                 TreeNode right = constructRecursive(matches);
                 TreeNode left = constructRecursive(matches);
                 if (left == null || right == null) return null;
-                else return new BinaryInfixNode(operator, left, right);
+                else return new BinaryNode(operator, left, right);
             } else {
                 TreeNode applyTo = constructRecursive(matches);
                 if (applyTo == null) return null;
-                else return new UnaryPrefixNode(operator, applyTo);
+                else return new UnaryNode(operator, applyTo);
             }
         } else if (matchType == TokenType.NUM) {
             return new NumberNode(abacus.numberFromString(match.getContent()));

src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java

@@ -52,6 +52,20 @@ public class StandardPlugin extends Plugin {
             return params[0].subtract(params[1]);
         }
     });
+    /**
+     * The negation operator, -
+     */
+    public static final Operator OP_NEGATE = new Operator(OperatorAssociativity.LEFT, OperatorType.UNARY_PREFIX, 0, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return params[0].negate();
+        }
+    });
     /**
      * The multiplication operator, *
      */
@@ -317,6 +331,7 @@ public class StandardPlugin extends Plugin {
 
         registerOperator("+", OP_ADD);
         registerOperator("-", OP_SUBTRACT);
+        registerOperator("`", OP_NEGATE);
         registerOperator("*", OP_MULTIPLY);
         registerOperator("/", OP_DIVIDE);
         registerOperator("^", OP_CARET);
@@ -335,7 +350,7 @@ public class StandardPlugin extends Plugin {
 
     public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n){
         if(!factorialLists.containsKey(numberClass)){
-            factorialLists.put(numberClass, new ArrayList<NumberInterface>());
+            factorialLists.put(numberClass, new ArrayList<>());
             factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
             factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
         }

src/main/java/org/nwapw/abacus/tree/BinaryNode.java

@@ -3,7 +3,7 @@ package org.nwapw.abacus.tree;
 /**
  * A tree node that represents an operation being applied to two operands.
  */
-public class BinaryInfixNode extends TreeNode {
+public class BinaryNode extends TreeNode {
 
     /**
      * The operation being applied.
@@ -18,7 +18,7 @@ public class BinaryInfixNode extends TreeNode {
      */
     private TreeNode right;
 
-    private BinaryInfixNode() {
+    private BinaryNode() {
     }
 
     /**
@@ -27,7 +27,7 @@ public class BinaryInfixNode extends TreeNode {
      *
      * @param operation the operation.
      */
-    public BinaryInfixNode(String operation) {
+    public BinaryNode(String operation) {
         this(operation, null, null);
     }
 
@@ -39,7 +39,7 @@ public class BinaryInfixNode extends TreeNode {
      * @param left      the left node of the expression.
      * @param right     the right node of the expression.
      */
-    public BinaryInfixNode(String operation, TreeNode left, TreeNode right) {
+    public BinaryNode(String operation, TreeNode left, TreeNode right) {
         this.operation = operation;
         this.left = left;
         this.right = right;

src/main/java/org/nwapw/abacus/tree/NumberReducer.java

@@ -28,15 +28,15 @@ public class NumberReducer implements Reducer<NumberInterface> {
     public NumberInterface reduceNode(TreeNode node, Object... children) {
         if (node instanceof NumberNode) {
             return ((NumberNode) node).getNumber();
-        } else if (node instanceof BinaryInfixNode) {
+        } else if (node instanceof BinaryNode) {
             NumberInterface left = (NumberInterface) children[0];
             NumberInterface right = (NumberInterface) children[1];
-            Function function = abacus.getPluginManager().operatorFor(((BinaryInfixNode) node).getOperation()).getFunction();
+            Function function = abacus.getPluginManager().operatorFor(((BinaryNode) node).getOperation()).getFunction();
             if (function == null) return null;
             return function.apply(left, right);
-        } else if (node instanceof UnaryPrefixNode) {
+        } else if (node instanceof UnaryNode) {
             NumberInterface child = (NumberInterface) children[0];
-            Function functionn = abacus.getPluginManager().operatorFor(((UnaryPrefixNode) node).getOperation()).getFunction();
+            Function functionn = abacus.getPluginManager().operatorFor(((UnaryNode) node).getOperation()).getFunction();
             if (functionn == null) return null;
             return functionn.apply(child);
         } else if (node instanceof FunctionNode) {

src/main/java/org/nwapw/abacus/tree/UnaryNode.java

@@ -1,6 +1,6 @@
 package org.nwapw.abacus.tree;
 
-public class UnaryPrefixNode extends TreeNode {
+public class UnaryNode extends TreeNode {
 
     /**
      * The operation this node will apply.
@@ -16,7 +16,7 @@ public class UnaryPrefixNode extends TreeNode {
      *
      * @param operation the operation for this node.
      */
-    public UnaryPrefixNode(String operation) {
+    public UnaryNode(String operation) {
         this(operation, null);
     }
 
@@ -26,7 +26,7 @@ public class UnaryPrefixNode extends TreeNode {
      * @param operation the operation for this node.
      * @param applyTo   the node to apply the function to.
      */
-    public UnaryPrefixNode(String operation, TreeNode applyTo) {
+    public UnaryNode(String operation, TreeNode applyTo) {
         this.operation = operation;
         this.applyTo = applyTo;
     }

src/main/resources/abacus.fxml

@@ -5,6 +5,8 @@
 <?import javafx.scene.layout.BorderPane?>
 <?import javafx.scene.layout.VBox?>
 <?import javafx.scene.text.Text?>
+<?import javafx.scene.layout.HBox?>
+<?import javafx.scene.layout.GridPane?>
 <BorderPane xmlns="http://javafx.com/javafx"
             xmlns:fx="http://javafx.com/fxml"
             fx:controller="org.nwapw.abacus.fx.AbacusController">
@@ -39,7 +41,13 @@
                     </bottom>
                 </BorderPane>
             </Tab>
-            <Tab text="Settings" closable="false"/>
+            <Tab text="Settings" closable="false">
+                <GridPane hgap="10" vgap="10">
+                    <padding><Insets left="10" right="10" top="10" bottom="10"/></padding>
+                    <Label text="Number Implementation" GridPane.columnIndex="0" GridPane.rowIndex="0"/>
+                    <ComboBox fx:id="numberImplementationBox" GridPane.columnIndex="1" GridPane.rowIndex="0"/>
+                </GridPane>
+            </Tab>
         </TabPane>
     </center>