Merge branch 'master' into plugin-conversions

Fix crash when a TreeValueFunction doesn't have documentation loaded.

core/src/main/java/org/nwapw/abacus/lexing/Lexer.java

@@ -1,9 +1,8 @@
 package org.nwapw.abacus.lexing;
 
-import org.nwapw.abacus.lexing.pattern.EndNode;
-import org.nwapw.abacus.lexing.pattern.Match;
 import org.nwapw.abacus.lexing.pattern.Pattern;
-import org.nwapw.abacus.lexing.pattern.PatternNode;
+import org.nwapw.abacus.lexing.pattern.nodes.EndNode;
+import org.nwapw.abacus.lexing.pattern.nodes.PatternNode;
 
 import java.util.*;
 
@@ -80,10 +79,10 @@ public class Lexer<T> {
 
             index++;
         }
-        matches.sort((a, b) -> compare.compare(a.getType(), b.getType()));
         if (compare != null) {
-            matches.sort(Comparator.comparingInt(a -> a.getContent().length()));
+            Collections.sort(matches, (a, b) -> compare.compare(a.getType(), b.getType()));
         }
+        Collections.sort(matches, (o1, o2) -> o1.getContent().length() - o2.getContent().length());
         return matches.isEmpty() ? null : matches.get(matches.size() - 1);
     }
 
@@ -137,7 +136,10 @@ public class Lexer<T> {
 
         @Override
         public int hashCode() {
-            return Objects.hash(name, id);
+            return Arrays.hashCode(new Object[] {
+                    this.name,
+                    this.id
+            });
         }
 
         @Override

core/src/main/java/org/nwapw/abacus/lexing/Match.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.lexing.pattern;
+package org.nwapw.abacus.lexing;
 
 /**
  * A match that has been generated by the lexer.

core/src/main/java/org/nwapw/abacus/lexing/pattern/Pattern.java

@@ -1,10 +1,11 @@
 package org.nwapw.abacus.lexing.pattern;
 
+import org.nwapw.abacus.lexing.pattern.nodes.*;
+
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Stack;
-import java.util.function.Function;
 
 /**
  * A pattern that can be compiled from a string and used in lexing.
@@ -34,8 +35,8 @@ public class Pattern<T> {
      * A map of regex operator to functions that modify a PatternChain
      * with the appropriate operation.
      */
-    private Map<Character, Function<PatternChain<T>, PatternChain<T>>> operations =
-            new HashMap<Character, Function<PatternChain<T>, PatternChain<T>>>() {{
+    private Map<Character, Transformation<T>> operations =
+            new HashMap<Character, Transformation<T>>() {{
                 put('+', Pattern.this::transformPlus);
                 put('*', Pattern.this::transformStar);
                 put('?', Pattern.this::transformQuestion);
@@ -88,7 +89,7 @@ public class Pattern<T> {
      * @return the modified chain.
      */
     private PatternChain<T> transformPlus(PatternChain<T> chain) {
-        chain.tail.outputStates.add(chain.head);
+        chain.tail.getOutputStates().add(chain.head);
         return chain;
     }
 
@@ -102,10 +103,10 @@ public class Pattern<T> {
     private PatternChain<T> transformStar(PatternChain<T> chain) {
         LinkNode<T> newTail = new LinkNode<>();
         LinkNode<T> newHead = new LinkNode<>();
-        newHead.outputStates.add(chain.head);
-        newHead.outputStates.add(newTail);
-        chain.tail.outputStates.add(newTail);
-        newTail.outputStates.add(newHead);
+        newHead.getOutputStates().add(chain.head);
+        newHead.getOutputStates().add(newTail);
+        chain.tail.getOutputStates().add(newTail);
+        newTail.getOutputStates().add(newHead);
         chain.head = newHead;
         chain.tail = newTail;
         return chain;
@@ -121,9 +122,9 @@ public class Pattern<T> {
     private PatternChain<T> transformQuestion(PatternChain<T> chain) {
         LinkNode<T> newTail = new LinkNode<>();
         LinkNode<T> newHead = new LinkNode<>();
-        newHead.outputStates.add(chain.head);
-        newHead.outputStates.add(newTail);
-        chain.tail.outputStates.add(newTail);
+        newHead.getOutputStates().add(chain.head);
+        newHead.getOutputStates().add(newTail);
+        chain.tail.getOutputStates().add(newTail);
         chain.head = newHead;
         chain.tail = newTail;
         return chain;
@@ -140,8 +141,8 @@ public class Pattern<T> {
         LinkNode<T> tail = new LinkNode<>();
         PatternChain<T> newChain = new PatternChain<>(head, tail);
         for (PatternChain<T> chain : collection) {
-            head.outputStates.add(chain.head);
-            chain.tail.outputStates.add(tail);
+            head.getOutputStates().add(chain.head);
+            chain.tail.getOutputStates().add(tail);
         }
         return newChain;
     }
@@ -205,7 +206,7 @@ public class Pattern<T> {
             if (operations.containsKey(currentChar)) {
                 if (currentChain == null) return null;
 
-                currentChain = operations.get(currentChar).apply(currentChain);
+                currentChain = operations.get(currentChar).transform(currentChain);
                 fullChain.append(currentChain);
                 currentChain = null;
                 index++;

core/src/main/java/org/nwapw/abacus/lexing/pattern/PatternChain.java

@@ -1,5 +1,7 @@
 package org.nwapw.abacus.lexing.pattern;
 
+import org.nwapw.abacus.lexing.pattern.nodes.PatternNode;
+
 /**
  * A chain of nodes that can be treated as a single unit.
  * Used during pattern compilation.
@@ -56,7 +58,7 @@ public class PatternChain<T> {
             this.head = other.head;
             this.tail = other.tail;
         } else {
-            tail.outputStates.add(other.head);
+            tail.getOutputStates().add(other.head);
             tail = other.tail;
         }
     }
@@ -72,7 +74,7 @@ public class PatternChain<T> {
         if (tail == null) {
             head = tail = node;
         } else {
-            tail.outputStates.add(node);
+            tail.getOutputStates().add(node);
             tail = node;
         }
     }

core/src/main/java/org/nwapw/abacus/lexing/pattern/Transformation.java

@@ -0,0 +1,16 @@
+package org.nwapw.abacus.lexing.pattern;
+
+/**
+ * An interface that transforms a pattern chain into a different pattern chain.
+ * @param <T> the type used to identify the nodes in the pattern chain.
+ */
+public interface Transformation<T> {
+
+    /**
+     * Performs the actual transformation.
+     * @param from the original chain.
+     * @return the resulting chain.
+     */
+    PatternChain<T> transform(PatternChain<T> from);
+
+}

core/src/main/java/org/nwapw/abacus/lexing/pattern/nodes/AnyNode.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.lexing.pattern;
+package org.nwapw.abacus.lexing.pattern.nodes;
 
 /**
  * A pattern node that matches any character.

core/src/main/java/org/nwapw/abacus/lexing/pattern/nodes/EndNode.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.lexing.pattern;
+package org.nwapw.abacus.lexing.pattern.nodes;
 
 /**
  * A node that represents a successful match.

core/src/main/java/org/nwapw/abacus/lexing/pattern/nodes/LinkNode.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.lexing.pattern;
+package org.nwapw.abacus.lexing.pattern.nodes;
 
 import java.util.Collection;
 

core/src/main/java/org/nwapw/abacus/lexing/pattern/nodes/PatternNode.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.lexing.pattern;
+package org.nwapw.abacus.lexing.pattern.nodes;
 
 import java.util.Collection;
 import java.util.HashSet;
@@ -65,4 +65,11 @@ public class PatternNode<T> {
         outputStates.forEach(e -> e.addInto(into));
     }
 
+    /**
+     * Gets the output states of this node.
+     * @return the output states.
+     */
+    public Set<PatternNode<T>> getOutputStates() {
+        return outputStates;
+    }
 }

core/src/main/java/org/nwapw/abacus/lexing/pattern/nodes/RangeNode.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.lexing.pattern;
+package org.nwapw.abacus.lexing.pattern.nodes;
 
 /**
  * A node that matches a range of characters.

core/src/main/java/org/nwapw/abacus/lexing/pattern/nodes/ValueNode.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.lexing.pattern;
+package org.nwapw.abacus.lexing.pattern.nodes;
 
 /**
  * A node that matches a single value.

core/src/main/java/org/nwapw/abacus/number/standard/NaiveNumber.java

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.number;
+package org.nwapw.abacus.number.standard;
+
+import org.nwapw.abacus.number.NumberInterface;
 
 /**
  * An implementation of NumberInterface using a double.

core/src/main/java/org/nwapw/abacus/number/standard/PreciseNumber.java

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.number;
+package org.nwapw.abacus.number.standard;
+
+import org.nwapw.abacus.number.NumberInterface;
 
 import java.math.BigDecimal;
 import java.math.MathContext;

core/src/main/java/org/nwapw/abacus/parsing/standard/LexerTokenizer.java

@@ -1,12 +1,12 @@
-package org.nwapw.abacus.parsing;
+package org.nwapw.abacus.parsing.standard;
 
 import org.nwapw.abacus.exception.TokenizeException;
 import org.nwapw.abacus.lexing.Lexer;
-import org.nwapw.abacus.lexing.pattern.Match;
+import org.nwapw.abacus.lexing.Match;
 import org.nwapw.abacus.lexing.pattern.Pattern;
+import org.nwapw.abacus.parsing.Tokenizer;
 import org.nwapw.abacus.plugin.PluginListener;
 import org.nwapw.abacus.plugin.PluginManager;
-import org.nwapw.abacus.tree.TokenType;
 
 import java.util.Comparator;
 import java.util.List;
@@ -20,7 +20,7 @@ public class LexerTokenizer implements Tokenizer<Match<TokenType>>, PluginListen
     /**
      * Comparator used to sort the tokens produced by the lexer.
      */
-    protected static final Comparator<TokenType> TOKEN_SORTER = Comparator.comparingInt(e -> e.priority);
+    protected static final Comparator<TokenType> TOKEN_SORTER = (o1, o2) -> o1.priority - o2.priority;
 
     /**
      * The lexer instance used to turn strings into matches.

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

@@ -1,13 +1,14 @@
-package org.nwapw.abacus.parsing;
+package org.nwapw.abacus.parsing.standard;
 
 import org.nwapw.abacus.exception.ParseException;
 import org.nwapw.abacus.function.Operator;
 import org.nwapw.abacus.function.OperatorAssociativity;
 import org.nwapw.abacus.function.OperatorType;
-import org.nwapw.abacus.lexing.pattern.Match;
+import org.nwapw.abacus.lexing.Match;
+import org.nwapw.abacus.parsing.Parser;
 import org.nwapw.abacus.plugin.PluginListener;
 import org.nwapw.abacus.plugin.PluginManager;
-import org.nwapw.abacus.tree.*;
+import org.nwapw.abacus.tree.nodes.*;
 
 import java.util.*;
 
@@ -162,7 +163,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
             matches.remove(0);
             CallNode node;
             if (matchType == TokenType.FUNCTION) {
-                node = new FunctionNode(functionName, children);
+                node = new NumberFunctionNode(functionName, children);
             } else {
                 node = new TreeValueFunctionNode(functionName, children);
             }

core/src/main/java/org/nwapw/abacus/parsing/standard/TokenType.java

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.tree;
+package org.nwapw.abacus.parsing.standard;
 
 /**
  * Enum to represent the type of the token that has been matched

core/src/main/java/org/nwapw/abacus/plugin/NumberImplementation.java

@@ -1,10 +1,10 @@
 package org.nwapw.abacus.plugin;
 
 import org.nwapw.abacus.number.NumberInterface;
+import org.nwapw.abacus.number.promotion.PromotionFunction;
 
 import java.util.HashMap;
 import java.util.Map;
-import java.util.function.Function;
 
 /**
  * A class that holds data about a number implementation.
@@ -14,7 +14,7 @@ public abstract class NumberImplementation {
     /**
      * The list of paths through which this implementation can be promoted.
      */
-    private Map<String, Function<NumberInterface, NumberInterface>> promotionPaths;
+    private Map<String, PromotionFunction> promotionPaths;
     /**
      * The implementation class for this implementation.
      */
@@ -41,7 +41,7 @@ public abstract class NumberImplementation {
      *
      * @return the map of documentation paths.
      */
-    public final Map<String, Function<NumberInterface, NumberInterface>> getPromotionPaths() {
+    public final Map<String, PromotionFunction> getPromotionPaths() {
         return promotionPaths;
     }
 

core/src/main/java/org/nwapw/abacus/plugin/Plugin.java

@@ -1,6 +1,11 @@
 package org.nwapw.abacus.plugin;
 
-import org.nwapw.abacus.function.*;
+import org.nwapw.abacus.function.Documentation;
+import org.nwapw.abacus.function.DocumentationType;
+import org.nwapw.abacus.function.interfaces.NumberFunction;
+import org.nwapw.abacus.function.interfaces.NumberOperator;
+import org.nwapw.abacus.function.interfaces.TreeValueFunction;
+import org.nwapw.abacus.function.interfaces.TreeValueOperator;
 import org.nwapw.abacus.number.NumberInterface;
 
 /**

core/src/main/java/org/nwapw/abacus/plugin/PluginManager.java

@@ -1,7 +1,12 @@
 package org.nwapw.abacus.plugin;
 
 import org.nwapw.abacus.Abacus;
-import org.nwapw.abacus.function.*;
+import org.nwapw.abacus.function.Documentation;
+import org.nwapw.abacus.function.DocumentationType;
+import org.nwapw.abacus.function.interfaces.NumberFunction;
+import org.nwapw.abacus.function.interfaces.NumberOperator;
+import org.nwapw.abacus.function.interfaces.TreeValueFunction;
+import org.nwapw.abacus.function.interfaces.TreeValueOperator;
 import org.nwapw.abacus.number.NumberInterface;
 
 import java.lang.reflect.InvocationTargetException;

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

@@ -1,10 +1,14 @@
 package org.nwapw.abacus.plugin.standard;
 
 import org.nwapw.abacus.context.MutableEvaluationContext;
-import org.nwapw.abacus.function.*;
-import org.nwapw.abacus.number.NaiveNumber;
+import org.nwapw.abacus.function.Documentation;
+import org.nwapw.abacus.function.DocumentationType;
+import org.nwapw.abacus.function.interfaces.NumberFunction;
+import org.nwapw.abacus.function.interfaces.NumberOperator;
+import org.nwapw.abacus.function.interfaces.TreeValueOperator;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.number.PreciseNumber;
+import org.nwapw.abacus.number.standard.NaiveNumber;
+import org.nwapw.abacus.number.standard.PreciseNumber;
 import org.nwapw.abacus.plugin.NumberImplementation;
 import org.nwapw.abacus.plugin.Plugin;
 import org.nwapw.abacus.plugin.PluginManager;

core/src/main/kotlin/org/nwapw/abacus/Abacus.kt

@@ -1,17 +1,15 @@
 package org.nwapw.abacus
 
 import org.nwapw.abacus.config.Configuration
-import org.nwapw.abacus.context.MutableEvaluationContext
 import org.nwapw.abacus.context.EvaluationContext
-import org.nwapw.abacus.number.PromotionManager
-import org.nwapw.abacus.parsing.LexerTokenizer
-import org.nwapw.abacus.parsing.ShuntingYardParser
+import org.nwapw.abacus.context.MutableEvaluationContext
+import org.nwapw.abacus.number.promotion.PromotionManager
 import org.nwapw.abacus.parsing.TreeBuilder
+import org.nwapw.abacus.parsing.standard.LexerTokenizer
+import org.nwapw.abacus.parsing.standard.ShuntingYardParser
 import org.nwapw.abacus.plugin.PluginManager
 import org.nwapw.abacus.plugin.standard.StandardPlugin
-import org.nwapw.abacus.tree.EvaluationResult
-import org.nwapw.abacus.tree.NumberReducer
-import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
  * Core class to handle all mathematics.
@@ -48,7 +46,7 @@ class Abacus(val configuration: Configuration) {
     /**
      * The hidden, mutable implementation of the context.
      */
-    private val mutableContext = MutableEvaluationContext(numberImplementation = StandardPlugin.IMPLEMENTATION_NAIVE)
+    private val mutableContext = MutableEvaluationContext(numberImplementation = StandardPlugin.IMPLEMENTATION_NAIVE, abacus = this)
     /**
      * The base context from which calculations are started.
      */
@@ -107,9 +105,8 @@ class Abacus(val configuration: Configuration) {
      * @return the evaluation result.
      */
     fun evaluateTreeWithContext(tree: TreeNode, context: MutableEvaluationContext): EvaluationResult {
-        val newReducer = NumberReducer(this, context)
-        val evaluationValue = tree.reduce(newReducer)
-        return EvaluationResult(evaluationValue, newReducer.context)
+        val evaluationValue = tree.reduce(context)
+        return EvaluationResult(evaluationValue, context)
     }
 
 }

core/src/main/kotlin/org/nwapw/abacus/EvaluationResult.kt

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus
 
 import org.nwapw.abacus.context.MutableEvaluationContext
 import org.nwapw.abacus.number.NumberInterface

core/src/main/kotlin/org/nwapw/abacus/context/EvaluationContext.kt

@@ -1,9 +1,10 @@
 package org.nwapw.abacus.context
 
+import org.nwapw.abacus.Abacus
 import org.nwapw.abacus.number.NumberInterface
 import org.nwapw.abacus.plugin.NumberImplementation
 import org.nwapw.abacus.tree.Reducer
-import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
  * A context for the reduction of a [org.nwapw.abacus.tree.TreeNode] into a number.
@@ -13,11 +14,11 @@ import org.nwapw.abacus.tree.TreeNode
  *
  * @property parent the parent of this context.
  * @property numberImplementation the implementation for numbers of this context.
- * @property reducer the reducer used by this context.
+ * @property abacus the abacus instance used by this reducer.
  */
-open class EvaluationContext(val parent: EvaluationContext? = null,
-                             open val numberImplementation: NumberImplementation? = null,
-                             open val reducer: Reducer<NumberInterface>? = null) {
+abstract class EvaluationContext(val parent: EvaluationContext? = null,
+                                 open val numberImplementation: NumberImplementation? = null,
+                                 open val abacus: Abacus? = null): Reducer<NumberInterface> {
 
     /**
      * The map of variables in this context.
@@ -47,10 +48,10 @@ open class EvaluationContext(val parent: EvaluationContext? = null,
             by ChainSearchDelegate { numberImplementation }
 
     /**
-     * The reducer inherited from this context's parent.
+     * The Abacus instance inherited from this context's parent.
      */
-    val inheritedReducer: Reducer<NumberInterface>
-            by ChainSearchDelegate { reducer }
+    val inheritedAbacus: Abacus
+            by ChainSearchDelegate { abacus }
 
     /**
      * The set of all variables in this context and its parents.

core/src/main/kotlin/org/nwapw/abacus/context/MutableEvaluationContext.kt

@@ -1,9 +1,11 @@
 package org.nwapw.abacus.context
 
+import org.nwapw.abacus.Abacus
+import org.nwapw.abacus.exception.NumberReducerException
+import org.nwapw.abacus.exception.ReductionException
 import org.nwapw.abacus.number.NumberInterface
 import org.nwapw.abacus.plugin.NumberImplementation
-import org.nwapw.abacus.tree.Reducer
-import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.tree.nodes.*
 
 /**
  * A reduction context that is mutable.
@@ -13,11 +15,11 @@ import org.nwapw.abacus.tree.TreeNode
  */
 class MutableEvaluationContext(parent: EvaluationContext? = null,
                                numberImplementation: NumberImplementation? = null,
-                               reducer: Reducer<NumberInterface>? = null) :
-        EvaluationContext(parent, numberImplementation, reducer) {
+                               abacus: Abacus? = null) :
+        EvaluationContext(parent, numberImplementation, abacus) {
 
     override var numberImplementation: NumberImplementation? = super.numberImplementation
-    override var reducer: Reducer<NumberInterface>? = super.reducer
+    override var abacus: Abacus? = super.abacus
 
     /**
      * Writes data stored in the [other] context over data stored in this one.
@@ -25,7 +27,6 @@ class MutableEvaluationContext(parent: EvaluationContext? = null,
      */
     fun apply(other: EvaluationContext) {
         if(other.numberImplementation != null) numberImplementation = other.numberImplementation
-        if(other.reducer != null) reducer = other.reducer
         for(name in other.variables) {
             setVariable(name, other.getVariable(name) ?: continue)
         }
@@ -66,4 +67,53 @@ class MutableEvaluationContext(parent: EvaluationContext? = null,
         definitionMap.clear()
     }
 
+    override fun reduceNode(treeNode: TreeNode, vararg children: Any): NumberInterface {
+        val abacus = inheritedAbacus
+        val promotionManager = abacus.promotionManager
+        return when(treeNode){
+            is NumberNode -> {
+                inheritedNumberImplementation.instanceForString(treeNode.number)
+            }
+            is VariableNode -> {
+                val variable = getVariable(treeNode.variable)
+                if(variable != null) return variable
+                val definition = getDefinition(treeNode.variable)
+                if(definition != null) return definition.reduce(this)
+                throw NumberReducerException("variable is not defined.")
+            }
+            is NumberUnaryNode -> {
+                val child = children[0] as NumberInterface
+                numberImplementation = abacus.pluginManager.interfaceImplementationFor(child.javaClass)
+                abacus.pluginManager.operatorFor(treeNode.operation)
+                        .apply(this, child)
+            }
+            is NumberBinaryNode -> {
+                val left = children[0] as NumberInterface
+                val right = children[1] as NumberInterface
+                val promotionResult = promotionManager.promote(left, right)
+                numberImplementation = promotionResult.promotedTo
+                abacus.pluginManager.operatorFor(treeNode.operation).apply(this, *promotionResult.items)
+            }
+            is NumberFunctionNode -> {
+                val promotionResult = promotionManager
+                        .promote(*children.map { it as NumberInterface }.toTypedArray())
+                numberImplementation = promotionResult.promotedTo
+                abacus.pluginManager.functionFor(treeNode.callTo).apply(this, *promotionResult.items)
+            }
+            is TreeValueUnaryNode -> {
+                abacus.pluginManager.treeValueOperatorFor(treeNode.operation)
+                        .apply(this, treeNode.applyTo)
+            }
+            is TreeValueBinaryNode -> {
+                abacus.pluginManager.treeValueOperatorFor(treeNode.operation)
+                        .apply(this, treeNode.left, treeNode.right)
+            }
+            is TreeValueFunctionNode -> {
+                abacus.pluginManager.treeValueFunctionFor(treeNode.callTo)
+                        .apply(this, *treeNode.children.toTypedArray())
+            }
+            else -> throw ReductionException("unrecognized tree node.")
+        }
+    }
+
 }

core/src/main/kotlin/org/nwapw/abacus/function/Applicable.kt

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.function.applicable
+package org.nwapw.abacus.function
 
 import org.nwapw.abacus.context.MutableEvaluationContext
 import org.nwapw.abacus.exception.DomainException

core/src/main/kotlin/org/nwapw/abacus/function/interfaces/NumberFunction.kt

@@ -1,6 +1,6 @@
-package org.nwapw.abacus.function
+package org.nwapw.abacus.function.interfaces
 
-import org.nwapw.abacus.function.applicable.Applicable
+import org.nwapw.abacus.function.Applicable
 import org.nwapw.abacus.number.NumberInterface
 
 /**

core/src/main/kotlin/org/nwapw/abacus/function/interfaces/NumberOperator.kt

@@ -1,6 +1,9 @@
-package org.nwapw.abacus.function
+package org.nwapw.abacus.function.interfaces
 
-import org.nwapw.abacus.function.applicable.Applicable
+import org.nwapw.abacus.function.Applicable
+import org.nwapw.abacus.function.Operator
+import org.nwapw.abacus.function.OperatorAssociativity
+import org.nwapw.abacus.function.OperatorType
 import org.nwapw.abacus.number.NumberInterface
 
 /**

core/src/main/kotlin/org/nwapw/abacus/function/interfaces/TreeValueFunction.kt

@@ -1,8 +1,8 @@
-package org.nwapw.abacus.function
+package org.nwapw.abacus.function.interfaces
 
-import org.nwapw.abacus.function.applicable.Applicable
+import org.nwapw.abacus.function.Applicable
 import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
  * A function that operates on trees.

core/src/main/kotlin/org/nwapw/abacus/function/interfaces/TreeValueOperator.kt

@@ -1,8 +1,11 @@
-package org.nwapw.abacus.function
+package org.nwapw.abacus.function.interfaces
 
-import org.nwapw.abacus.function.applicable.Applicable
+import org.nwapw.abacus.function.Applicable
+import org.nwapw.abacus.function.Operator
+import org.nwapw.abacus.function.OperatorAssociativity
+import org.nwapw.abacus.function.OperatorType
 import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
  * An operator that operates on trees.

core/src/main/kotlin/org/nwapw/abacus/number/NumberInterface.kt

@@ -1,6 +1,7 @@
 package org.nwapw.abacus.number
 
 import org.nwapw.abacus.exception.ComputationInterruptedException
+import org.nwapw.abacus.number.range.NumberRangeBuilder
 
 abstract class NumberInterface: Comparable<NumberInterface> {
 
@@ -220,6 +221,13 @@ abstract class NumberInterface: Comparable<NumberInterface> {
         return fractionalPartInternal()
     }
 
+    /**
+     * Checks whether the given number is an integer or not.
+     *
+     * @return whether the number is an integer or not.
+     */
+    fun isInteger() = fractionalPart().signum() == 0
+
     /**
      * Returns a NumberRangeBuilder object, which is used to create a range.
      * The reason that this returns a builder and not an actual range is that

core/src/main/kotlin/org/nwapw/abacus/number/promotion/NumberUtils.kt

@@ -1,7 +1,8 @@
 @file:JvmName("NumberUtils")
-package org.nwapw.abacus.number
+package org.nwapw.abacus.number.promotion
+
+import org.nwapw.abacus.number.NumberInterface
 
-typealias PromotionFunction = java.util.function.Function<NumberInterface, NumberInterface>
 typealias PromotionPath = List<PromotionFunction>
 typealias NumberClass = Class<NumberInterface>
 
@@ -12,5 +13,5 @@ typealias NumberClass = Class<NumberInterface>
  * @param from the number to start from.
  */
 fun PromotionPath.promote(from: NumberInterface): NumberInterface {
-    return fold(from, { current, function -> function.apply(current) })
+    return fold(from, { current, function -> function.promote(current) })
 }

core/src/main/kotlin/org/nwapw/abacus/number/promotion/PromotionFunction.kt

@@ -0,0 +1,20 @@
+package org.nwapw.abacus.number.promotion
+
+import org.nwapw.abacus.number.NumberInterface
+
+/**
+ * Function that is used to promote a number from one type to another.
+ *
+ * A promotion function is used in the promotion system as a mean to
+ * actually "travel" down the promotion path.
+ */
+interface PromotionFunction {
+
+    /**
+     * Promotes the given [number] into another type.
+     * @param number the number to promote from.
+     * @return the new number with the same value.
+     */
+    fun promote(number: NumberInterface): NumberInterface
+
+}

core/src/main/kotlin/org/nwapw/abacus/number/promotion/PromotionManager.kt

@@ -1,11 +1,11 @@
-package org.nwapw.abacus.number
+package org.nwapw.abacus.number.promotion
 
 import org.nwapw.abacus.Abacus
 import org.nwapw.abacus.exception.PromotionException
+import org.nwapw.abacus.number.NumberInterface
 import org.nwapw.abacus.plugin.NumberImplementation
 import org.nwapw.abacus.plugin.PluginListener
 import org.nwapw.abacus.plugin.PluginManager
-import java.util.function.Function
 
 /**
  * A class that handles promotions based on priority and the
@@ -31,7 +31,11 @@ class PromotionManager(val abacus: Abacus) : PluginListener {
         val fromName = abacus.pluginManager.interfaceImplementationNameFor(from.implementation)
         val toName = abacus.pluginManager.interfaceImplementationNameFor(to.implementation)
 
-        if(fromName == toName) return listOf(Function { it })
+        if(fromName == toName) return listOf(object : PromotionFunction {
+            override fun promote(number: NumberInterface): NumberInterface {
+                return number
+            }
+        })
 
         if(from.promotionPaths.containsKey(toName))
             return listOf(from.promotionPaths[toName] ?: return null)
@@ -51,7 +55,7 @@ class PromotionManager(val abacus: Abacus) : PluginListener {
         val implementations = numbers.map { pluginManager.interfaceImplementationFor(it.javaClass) }
         val highestPriority = implementations.sortedBy { it.priority }.last()
         return PromotionResult(items = numbers.map {
-            if(it.javaClass == highestPriority.implementation) it
+            if (it.javaClass == highestPriority.implementation) it
             else computePaths[pluginManager.interfaceImplementationFor(it.javaClass) to highestPriority]
                     ?.promote(it) ?: throw PromotionException()
         }.toTypedArray(), promotedTo = highestPriority)

core/src/main/kotlin/org/nwapw/abacus/number/promotion/PromotionResult.kt

@@ -1,5 +1,6 @@
-package org.nwapw.abacus.number
+package org.nwapw.abacus.number.promotion
 
+import org.nwapw.abacus.number.NumberInterface
 import org.nwapw.abacus.plugin.NumberImplementation
 
 /**

core/src/main/kotlin/org/nwapw/abacus/number/range/NumberRange.kt

@@ -1,6 +1,7 @@
-package org.nwapw.abacus.number
+package org.nwapw.abacus.number.range
 
 import org.nwapw.abacus.Abacus
+import org.nwapw.abacus.number.NumberInterface
 
 /**
  * A closed range designed specifically for [NumberInterface]

core/src/main/kotlin/org/nwapw/abacus/number/range/NumberRangeBuilder.kt

@@ -1,6 +1,7 @@
-package org.nwapw.abacus.number
+package org.nwapw.abacus.number.range
 
 import org.nwapw.abacus.Abacus
+import org.nwapw.abacus.number.NumberInterface
 
 /**
  * A utility class for creating [NumberRange] instances.

core/src/main/kotlin/org/nwapw/abacus/parsing/Parser.kt

@@ -1,6 +1,6 @@
 package org.nwapw.abacus.parsing
 
-import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
  * Converter from tokens into a parse tree.

core/src/main/kotlin/org/nwapw/abacus/parsing/TreeBuilder.kt

@@ -1,6 +1,6 @@
 package org.nwapw.abacus.parsing
 
-import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
  * Class to combine a [Tokenizer] and a [Parser]

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorAdd.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 
 /**

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorCaret.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 import org.nwapw.abacus.plugin.standard.StandardPlugin.*
 
@@ -17,7 +17,7 @@ class OperatorCaret: NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BI
     override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2
                     && !(params[0].signum() == 0 && params[1].signum() == 0)
-                    && !(params[0].signum() == -1 && params[1].fractionalPart().signum() != 0)
+                    && !(params[0].signum() == -1 && !params[1].isInteger())
 
     override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
         val implementation = context.inheritedNumberImplementation
@@ -26,7 +26,7 @@ class OperatorCaret: NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BI
         else if (params[1].signum() == 0)
             return implementation.instanceForString("1")
         //Detect integer bases:
-        if (params[0].fractionalPart().signum() == 0
+        if (params[0].isInteger()
                 && FUNCTION_ABS.apply(context, params[1]) < implementation.instanceForString(Integer.toString(Integer.MAX_VALUE))
                 && FUNCTION_ABS.apply(context, params[1]) >= implementation.instanceForString("1")) {
             val newParams = arrayOf(params[0], params[1].fractionalPart())

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorDefine.kt

@@ -3,10 +3,10 @@ package org.nwapw.abacus.plugin.standard.operator
 import org.nwapw.abacus.context.MutableEvaluationContext
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
-import org.nwapw.abacus.function.TreeValueOperator
+import org.nwapw.abacus.function.interfaces.TreeValueOperator
 import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.tree.TreeNode
-import org.nwapw.abacus.tree.VariableNode
+import org.nwapw.abacus.tree.nodes.TreeNode
+import org.nwapw.abacus.tree.nodes.VariableNode
 
 /**
  * The definition operator.
@@ -22,7 +22,7 @@ class OperatorDefine: TreeValueOperator(OperatorAssociativity.LEFT, OperatorType
     override fun applyInternal(context: MutableEvaluationContext, params: Array<out TreeNode>): NumberInterface {
         val assignTo = (params[0] as VariableNode).variable
         context.setDefinition(assignTo, params[1])
-        return params[1].reduce(context.inheritedReducer)
+        return params[1].reduce(context)
     }
 
 }

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorDivide.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 
 /**

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorFactorial.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 
 /**
@@ -15,7 +15,7 @@ class OperatorFactorial: NumberOperator(OperatorAssociativity.LEFT, OperatorType
 
     override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
         params.size == 1
-                && params[0].fractionalPart().signum() == 0
+                && params[0].isInteger()
                 && params[0].signum() >= 0
 
     override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>): NumberInterface {

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorMultiply.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 
 /**

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorNcr.kt

@@ -1,11 +1,12 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.plugin.standard.StandardPlugin.*
+import org.nwapw.abacus.plugin.standard.StandardPlugin.OP_FACTORIAL
+import org.nwapw.abacus.plugin.standard.StandardPlugin.OP_NPR
 
 /**
  * The "N choose R" operator.
@@ -16,8 +17,8 @@ import org.nwapw.abacus.plugin.standard.StandardPlugin.*
 class OperatorNcr: NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0) {
 
     override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
-            params.size == 2 && params[0].fractionalPart().signum() == 0
-                    && params[1].fractionalPart().signum() == 0
+            params.size == 2 && params[0].isInteger()
+                    && params[1].isInteger()
 
     override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
             OP_NPR.apply(context, *params) / OP_FACTORIAL.apply(context, params[1])

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorNegate.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 
 /**

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorNpr.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 
 /**
@@ -15,8 +15,8 @@ import org.nwapw.abacus.number.NumberInterface
 class OperatorNpr: NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0) {
 
     override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
-            params.size == 2 && params[0].fractionalPart().signum() == 0
-                    && params[1].fractionalPart().signum() == 0
+            params.size == 2 && params[0].isInteger()
+                    && params[1].isInteger()
 
     override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
         val implementation = context.inheritedNumberImplementation

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorSet.kt

@@ -3,10 +3,10 @@ package org.nwapw.abacus.plugin.standard.operator
 import org.nwapw.abacus.context.MutableEvaluationContext
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
-import org.nwapw.abacus.function.TreeValueOperator
+import org.nwapw.abacus.function.interfaces.TreeValueOperator
 import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.tree.TreeNode
-import org.nwapw.abacus.tree.VariableNode
+import org.nwapw.abacus.tree.nodes.TreeNode
+import org.nwapw.abacus.tree.nodes.VariableNode
 
 /**
  * The set operator.
@@ -20,7 +20,7 @@ class OperatorSet: TreeValueOperator(OperatorAssociativity.LEFT, OperatorType.BI
 
     override fun applyInternal(context: MutableEvaluationContext, params: Array<out TreeNode>): NumberInterface {
         val assignTo = (params[0] as VariableNode).variable
-        val value = params[1].reduce(context.inheritedReducer)
+        val value = params[1].reduce(context)
         context.setVariable(assignTo, value)
         return value
     }

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorSubtract.kt

@@ -1,9 +1,9 @@
 package org.nwapw.abacus.plugin.standard.operator
 
 import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.function.NumberOperator
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
+import org.nwapw.abacus.function.interfaces.NumberOperator
 import org.nwapw.abacus.number.NumberInterface
 
 /**

core/src/main/kotlin/org/nwapw/abacus/tree/NumberReducer.kt

@@ -1,65 +0,0 @@
-package org.nwapw.abacus.tree
-
-import org.nwapw.abacus.Abacus
-import org.nwapw.abacus.context.EvaluationContext
-import org.nwapw.abacus.exception.NumberReducerException
-import org.nwapw.abacus.exception.ReductionException
-import org.nwapw.abacus.number.NumberInterface
-
-class NumberReducer(val abacus: Abacus, context: EvaluationContext) : Reducer<NumberInterface> {
-
-    val context = context.mutableSubInstance()
-
-    init {
-        this.context.reducer = this
-    }
-
-    override fun reduceNode(treeNode: TreeNode, vararg children: Any): NumberInterface {
-        val promotionManager = abacus.promotionManager
-        return when(treeNode){
-            is NumberNode -> {
-                context.inheritedNumberImplementation.instanceForString(treeNode.number)
-            }
-            is VariableNode -> {
-                val variable = context.getVariable(treeNode.variable)
-                if(variable != null) return variable
-                val definition = context.getDefinition(treeNode.variable)
-                if(definition != null) return definition.reduce(this)
-                throw NumberReducerException("variable is not defined.")
-            }
-            is NumberUnaryNode -> {
-                val child = children[0] as NumberInterface
-                context.numberImplementation = abacus.pluginManager.interfaceImplementationFor(child.javaClass)
-                abacus.pluginManager.operatorFor(treeNode.operation)
-                        .apply(context, child)
-            }
-            is NumberBinaryNode -> {
-                val left = children[0] as NumberInterface
-                val right = children[1] as NumberInterface
-                val promotionResult = promotionManager.promote(left, right)
-                context.numberImplementation = promotionResult.promotedTo
-                abacus.pluginManager.operatorFor(treeNode.operation).apply(context, *promotionResult.items)
-            }
-            is FunctionNode -> {
-                val promotionResult = promotionManager
-                        .promote(*children.map { it as NumberInterface }.toTypedArray())
-                context.numberImplementation = promotionResult.promotedTo
-                abacus.pluginManager.functionFor(treeNode.callTo).apply(context, *promotionResult.items)
-            }
-            is TreeValueUnaryNode -> {
-                abacus.pluginManager.treeValueOperatorFor(treeNode.operation)
-                        .apply(context, treeNode.applyTo)
-            }
-            is TreeValueBinaryNode -> {
-                abacus.pluginManager.treeValueOperatorFor(treeNode.operation)
-                        .apply(context, treeNode.left, treeNode.right)
-            }
-            is TreeValueFunctionNode -> {
-                abacus.pluginManager.treeValueFunctionFor(treeNode.callTo)
-                        .apply(context, *treeNode.children.toTypedArray())
-            }
-            else -> throw ReductionException("unrecognized tree node.")
-        }
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/Reducer.kt

@@ -1,5 +1,7 @@
 package org.nwapw.abacus.tree
 
+import org.nwapw.abacus.tree.nodes.TreeNode
+
 /**
  * Reducer interface that takes a tree and returns a single value.
  *

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/BinaryNode.kt

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
 
 /**
  * A tree node that holds a binary operation.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/CallNode.kt

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
 
 /**
  * Represents a more generic function call.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/NumberBinaryNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A binary operator node that reduces its children.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/NumberFunctionNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A tree node that holds a function call.
@@ -8,7 +10,7 @@ package org.nwapw.abacus.tree
  *
  * @param function the function string.
  */
-class FunctionNode(function: String, children: List<TreeNode>) : CallNode(function, children) {
+class NumberFunctionNode(function: String, children: List<TreeNode>) : CallNode(function, children) {
 
     override fun <T : Any> reduce(reducer: Reducer<T>): T {
         val children = Array<Any>(children.size, { children[it].reduce(reducer) })

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/NumberNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A tree node that holds a single number value.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/NumberUnaryNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A unary operator node that reduces its children.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/TreeNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A tree node.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/TreeValueBinaryNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A tree node that represents a binary tree value operator.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/TreeValueFunctionNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A tree node that represents a tree value function call.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/TreeValueUnaryNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A tree node that represents a unary tree value operator.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/UnaryNode.kt

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
 
 /**
  * A tree node that holds a unary operation.

core/src/main/kotlin/org/nwapw/abacus/tree/nodes/VariableNode.kt

@@ -1,4 +1,6 @@
-package org.nwapw.abacus.tree
+package org.nwapw.abacus.tree.nodes
+
+import org.nwapw.abacus.tree.Reducer
 
 /**
  * A tree node that holds a placeholder variable.

core/src/test/java/org/nwapw/abacus/tests/CalculationTests.java

@@ -8,7 +8,7 @@ import org.nwapw.abacus.config.Configuration;
 import org.nwapw.abacus.exception.DomainException;
 import org.nwapw.abacus.number.NumberInterface;
 import org.nwapw.abacus.plugin.standard.StandardPlugin;
-import org.nwapw.abacus.tree.TreeNode;
+import org.nwapw.abacus.tree.nodes.TreeNode;
 
 public class CalculationTests {
 

core/src/test/java/org/nwapw/abacus/tests/LexerTests.java

@@ -3,7 +3,7 @@ package org.nwapw.abacus.tests;
 import org.junit.Assert;
 import org.junit.Test;
 import org.nwapw.abacus.lexing.Lexer;
-import org.nwapw.abacus.lexing.pattern.Match;
+import org.nwapw.abacus.lexing.Match;
 
 import java.util.List;
 

core/src/test/java/org/nwapw/abacus/tests/RangeTests.java

@@ -5,19 +5,17 @@ import org.junit.BeforeClass;
 import org.junit.Test;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.config.Configuration;
-import org.nwapw.abacus.number.NaiveNumber;
-import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.number.NumberRange;
-import org.nwapw.abacus.number.PreciseNumber;
+import org.nwapw.abacus.number.promotion.PromotionFunction;
+import org.nwapw.abacus.number.range.NumberRange;
+import org.nwapw.abacus.number.standard.NaiveNumber;
+import org.nwapw.abacus.number.standard.PreciseNumber;
 import org.nwapw.abacus.plugin.standard.StandardPlugin;
 
-import java.util.function.Function;
-
 public class RangeTests {
 
     private static Abacus abacus = new Abacus(new Configuration( "precise", new String[]{}));
-    private static Function<NumberInterface, NumberInterface> naivePromotion = i -> new NaiveNumber((i.toString()));
-    private static Function<NumberInterface, NumberInterface> precisePromotion = i -> new PreciseNumber((i.toString()));
+    private static PromotionFunction naivePromotion = i -> new NaiveNumber((i.toString()));
+    private static PromotionFunction precisePromotion = i -> new PreciseNumber((i.toString()));
 
     @BeforeClass
     public static void prepareTests() {

core/src/test/java/org/nwapw/abacus/tests/TokenizerTests.java

@@ -6,12 +6,15 @@ import org.junit.Test;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.config.Configuration;
 import org.nwapw.abacus.context.MutableEvaluationContext;
-import org.nwapw.abacus.function.*;
-import org.nwapw.abacus.lexing.pattern.Match;
+import org.nwapw.abacus.function.OperatorAssociativity;
+import org.nwapw.abacus.function.OperatorType;
+import org.nwapw.abacus.function.interfaces.NumberFunction;
+import org.nwapw.abacus.function.interfaces.NumberOperator;
+import org.nwapw.abacus.lexing.Match;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.parsing.LexerTokenizer;
+import org.nwapw.abacus.parsing.standard.LexerTokenizer;
+import org.nwapw.abacus.parsing.standard.TokenType;
 import org.nwapw.abacus.plugin.Plugin;
-import org.nwapw.abacus.tree.TokenType;
 
 import java.util.List;
 

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

@@ -16,12 +16,11 @@ import org.nwapw.abacus.exception.AbacusException;
 import org.nwapw.abacus.function.Documentation;
 import org.nwapw.abacus.function.DocumentationType;
 import org.nwapw.abacus.number.*;
-import org.nwapw.abacus.plugin.ClassFinder;
 import org.nwapw.abacus.plugin.PluginListener;
 import org.nwapw.abacus.plugin.PluginManager;
 import org.nwapw.abacus.plugin.standard.StandardPlugin;
-import org.nwapw.abacus.tree.EvaluationResult;
-import org.nwapw.abacus.tree.TreeNode;
+import org.nwapw.abacus.EvaluationResult;
+import org.nwapw.abacus.tree.nodes.TreeNode;
 
 import java.io.File;
 import java.io.IOException;
@@ -360,10 +359,13 @@ public class AbacusController implements PluginListener {
             if(documentationInstance == null)
                 documentationInstance = new Documentation(name, "", "", "", DocumentationType.FUNCTION);
             return documentationInstance;
-        })
-                .collect(Collectors.toCollection(ArrayList::new)));
-        functionList.addAll(manager.getAllTreeValueFunctions().stream().map(name -> pluginManager.documentationFor(name, DocumentationType.TREE_VALUE_FUNCTION))
-                .collect(Collectors.toCollection(ArrayList::new)));
+        }).collect(Collectors.toCollection(ArrayList::new)));
+        functionList.addAll(manager.getAllTreeValueFunctions().stream().map(name -> {
+            Documentation documentationInstance = pluginManager.documentationFor(name, DocumentationType.TREE_VALUE_FUNCTION);
+            if(documentationInstance == null)
+                documentationInstance = new Documentation(name, "", "", "", DocumentationType.TREE_VALUE_FUNCTION);
+            return documentationInstance;
+        }).collect(Collectors.toCollection(ArrayList::new)));
         functionList.sort(Comparator.comparing(Documentation::getCodeName));
     }
 

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

@@ -1,4 +1,4 @@
-package org.nwapw.abacus.plugin;
+package org.nwapw.abacus.fx;
 
 import java.io.File;
 import java.io.IOException;