Add an additional, restricted type of context for use only by plugins.

Move all the number reducer functionality into the context.

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

@@ -1,7 +1,7 @@
 package org.nwapw.abacus.lexing;
 
-import org.nwapw.abacus.lexing.pattern.nodes.EndNode;
 import org.nwapw.abacus.lexing.pattern.Pattern;
+import org.nwapw.abacus.lexing.pattern.nodes.EndNode;
 import org.nwapw.abacus.lexing.pattern.nodes.PatternNode;
 
 import java.util.*;

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

@@ -1,6 +1,7 @@
 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;

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

@@ -1,7 +1,8 @@
 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;

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

@@ -1,12 +1,15 @@
 package org.nwapw.abacus.plugin.standard;
 
+import org.jetbrains.annotations.NotNull;
 import org.nwapw.abacus.context.MutableEvaluationContext;
-import org.nwapw.abacus.function.*;
+import org.nwapw.abacus.context.PluginEvaluationContext;
+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.standard.NaiveNumber;
 import org.nwapw.abacus.number.NumberInterface;
+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;
@@ -118,12 +121,12 @@ public class StandardPlugin extends Plugin {
      */
     public static final NumberFunction FUNCTION_ABS = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return params[0].multiply(context.getInheritedNumberImplementation().instanceForString(Integer.toString(params[0].signum())));
         }
     };
@@ -132,12 +135,12 @@ public class StandardPlugin extends Plugin {
      */
     public static final NumberFunction FUNCTION_LN = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1 && params[0].compareTo(context.getInheritedNumberImplementation().instanceForString("0")) > 0;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             NumberImplementation implementation = context.getInheritedNumberImplementation();
             NumberInterface param = params[0];
             NumberInterface one = implementation.instanceForString("1");
@@ -165,10 +168,12 @@ public class StandardPlugin extends Plugin {
         /**
          * Returns the partial sum of the Taylor series for logx (around x=1).
          * Automatically determines the number of terms needed based on the precision of x.
+         *
+         * @param context
          * @param x value at which the series is evaluated. 0 < x < 2. (x=2 is convergent but impractical.)
          * @return the partial sum.
          */
-        private NumberInterface getLogPartialSum(MutableEvaluationContext context, NumberInterface x) {
+        private NumberInterface getLogPartialSum(PluginEvaluationContext context, NumberInterface x) {
             NumberImplementation implementation = context.getInheritedNumberImplementation();
             NumberInterface maxError = x.getMaxError();
             x = x.subtract(implementation.instanceForString("1")); //Terms used are for log(x+1).
@@ -213,12 +218,12 @@ public class StandardPlugin extends Plugin {
      */
     public static final NumberFunction FUNCTION_RAND_INT = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return context.getInheritedNumberImplementation().instanceForString(Long.toString(Math.round(Math.random() * params[0].floor().intValue())));
         }
     };
@@ -231,12 +236,12 @@ public class StandardPlugin extends Plugin {
      */
     public static final NumberFunction FUNCTION_SQRT = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return OP_CARET.apply(context, params[0], context.getInheritedNumberImplementation().instanceForString(".5"));
         }
     };
@@ -246,12 +251,12 @@ public class StandardPlugin extends Plugin {
      */
     public static final NumberFunction FUNCTION_EXP = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             NumberImplementation implementation = context.getInheritedNumberImplementation();
             NumberInterface maxError = params[0].getMaxError();
             int n = 0;
@@ -284,12 +289,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionSin = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             NumberImplementation implementation = context.getInheritedNumberImplementation();
             NumberInterface pi = piFor(params[0].getClass());
             NumberInterface twoPi = pi.multiply(implementation.instanceForString("2"));
@@ -309,12 +314,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionCos = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return functionSin.apply(context, piFor(params[0].getClass()).divide(context.getInheritedNumberImplementation().instanceForString("2"))
                     .subtract(params[0]));
         }
@@ -324,12 +329,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionTan = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return functionSin.apply(context, params[0]).divide(functionCos.apply(context, params[0]));
         }
     };
@@ -338,12 +343,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionSec = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return context.getInheritedNumberImplementation().instanceForString("1").divide(functionCos.apply(context, params[0]));
         }
     };
@@ -352,12 +357,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionCsc = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return context.getInheritedNumberImplementation().instanceForString("1").divide(functionSin.apply(context, params[0]));
         }
     };
@@ -366,12 +371,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionCot = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return functionCos.apply(context, params[0]).divide(functionSin.apply(context, params[0]));
         }
     };
@@ -381,13 +386,13 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionArcsin = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1
                     && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) <= 0;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             NumberImplementation implementation = context.getInheritedNumberImplementation();
             if (FUNCTION_ABS.apply(context, params[0]).compareTo(implementation.instanceForString(".8")) >= 0) {
                 NumberInterface[] newParams = {FUNCTION_SQRT.apply(context, implementation.instanceForString("1").subtract(params[0].multiply(params[0])))};
@@ -415,12 +420,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionArccos = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1 && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) <= 0;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return piFor(params[0].getClass()).divide(context.getInheritedNumberImplementation().instanceForString("2"))
                     .subtract(functionArcsin.apply(context, params));
         }
@@ -431,12 +436,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionArccsc = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1 && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) >= 0;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             NumberInterface[] reciprocalParamArr = {context.getInheritedNumberImplementation().instanceForString("1").divide(params[0])};
             return functionArcsin.apply(context, reciprocalParamArr);
         }
@@ -447,12 +452,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionArcsec = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1 && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) >= 0;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             NumberInterface[] reciprocalParamArr = {context.getInheritedNumberImplementation().instanceForString("1").divide(params[0])};
             return functionArccos.apply(context, reciprocalParamArr);
         }
@@ -463,12 +468,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionArctan = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             NumberImplementation implementation = context.getInheritedNumberImplementation();
             if (params[0].signum() == -1) {
                 NumberInterface[] negatedParams = {params[0].negate()};
@@ -505,12 +510,12 @@ public class StandardPlugin extends Plugin {
      */
     public final NumberFunction functionArccot = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return piFor(params[0].getClass()).divide(context.getInheritedNumberImplementation().instanceForString("2"))
                     .subtract(functionArctan.apply(context, params));
         }
@@ -549,7 +554,7 @@ public class StandardPlugin extends Plugin {
      * @param x where the series is evaluated.
      * @return the value of the series
      */
-    private static NumberInterface sinTaylor(MutableEvaluationContext context, NumberInterface x) {
+    private static NumberInterface sinTaylor(PluginEvaluationContext context, NumberInterface x) {
         NumberInterface power = x, multiplier = x.multiply(x).negate(), currentTerm, sum = x;
         NumberInterface maxError = x.getMaxError();
         int n = 1;
@@ -568,7 +573,7 @@ public class StandardPlugin extends Plugin {
      * @param phi an angle (in radians).
      * @return theta in [0, 2pi) that differs from phi by a multiple of 2pi.
      */
-    private static NumberInterface getSmallAngle(MutableEvaluationContext context, NumberInterface phi, NumberInterface pi) {
+    private static NumberInterface getSmallAngle(PluginEvaluationContext context, NumberInterface phi, NumberInterface pi) {
         NumberInterface twoPi = pi.multiply(context.getInheritedNumberImplementation().instanceForString("2"));
         NumberInterface theta = FUNCTION_ABS.apply(context, phi).subtract(twoPi
                 .multiply(FUNCTION_ABS.apply(context, phi).divide(twoPi).floor())); //Now theta is in [0, 2pi).

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

@@ -1,15 +1,14 @@
 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.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.parsing.TreeBuilder
 import org.nwapw.abacus.plugin.PluginManager
 import org.nwapw.abacus.plugin.standard.StandardPlugin
-import org.nwapw.abacus.tree.standard.NumberReducer
 import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
@@ -47,7 +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.
      */
@@ -106,9 +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(context)
-        val evaluationValue = tree.reduce(newReducer)
+        return EvaluationResult(evaluationValue, context)
-        return EvaluationResult(evaluationValue, newReducer.context)
     }
 
 }

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

@@ -1,5 +1,6 @@
 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
@@ -13,11 +14,11 @@ import org.nwapw.abacus.tree.nodes.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,
+abstract class EvaluationContext(val parent: EvaluationContext? = null,
                                  open val numberImplementation: NumberImplementation? = null,
-                             open val reducer: Reducer<NumberInterface>? = 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>
+    val inheritedAbacus: Abacus
-            by ChainSearchDelegate { reducer }
+            by ChainSearchDelegate { abacus }
 
     /**
      * The set of all variables in this context and its parents.

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

@@ -1,23 +1,26 @@
 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.nodes.*
-import org.nwapw.abacus.tree.nodes.TreeNode
 
 /**
  * A reduction context that is mutable.
+ *
  * @param parent the parent of this context.
  * @param numberImplementation the number implementation used in this context.
- * @param reducer the reducer used in this context
+ * @param abacus the abacus instance used.
  */
 class MutableEvaluationContext(parent: EvaluationContext? = null,
                                numberImplementation: NumberImplementation? = null,
-                               reducer: Reducer<NumberInterface>? = null) :
+                               abacus: Abacus? = null) :
-        EvaluationContext(parent, numberImplementation, reducer) {
+        PluginEvaluationContext(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 +28,6 @@ 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)
         }
@@ -34,36 +36,56 @@ class MutableEvaluationContext(parent: EvaluationContext? = null,
         }
     }
 
-    /**
+    override fun reduceNode(treeNode: TreeNode, vararg children: Any): NumberInterface {
-     * Sets a variable to a certain [value].
+        val oldNumberImplementation = numberImplementation
-     * @param name the name of the variable.
+        val abacus = inheritedAbacus
-     * @param value the value of the variable.
+        val promotionManager = abacus.promotionManager
-     */
+        val toReturn = when(treeNode){
-    fun setVariable(name: String, value: NumberInterface) {
+            is NumberNode -> {
-        variableMap[name] = value
+                inheritedNumberImplementation.instanceForString(treeNode.number)
             }
-
+            is VariableNode -> {
-    /**
+                val variable = getVariable(treeNode.variable)
-     * Set a definition to a certain [value].
+                if(variable != null) return variable
-     * @param name the name of the definition.
+                val definition = getDefinition(treeNode.variable)
-     * @param value the value of the definition.
+                if(definition != null) return definition.reduce(this)
-     */
+                throw NumberReducerException("variable is not defined.")
-    fun setDefinition(name: String, value: TreeNode) {
-        definitionMap[name] = value
             }
-
+            is NumberUnaryNode -> {
-    /**
+                val child = children[0] as NumberInterface
-     * Clears the variables defined in this context.
+                numberImplementation = abacus.pluginManager.interfaceImplementationFor(child.javaClass)
-     */
+                abacus.pluginManager.operatorFor(treeNode.operation)
-    fun clearVariables(){
+                        .apply(this, child)
-        variableMap.clear()
             }
-
+            is NumberBinaryNode -> {
-    /**
+                val left = children[0] as NumberInterface
-     * Clears the definitions defined in this context.
+                val right = children[1] as NumberInterface
-     */
+                val promotionResult = promotionManager.promote(left, right)
-    fun clearDefinitions(){
+                numberImplementation = promotionResult.promotedTo
-        definitionMap.clear()
+                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.")
+        }
+        numberImplementation = oldNumberImplementation
+        return toReturn
     }
 
 }

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

@@ -0,0 +1,58 @@
+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.nodes.TreeNode
+
+/**
+ * An evaluation context with limited mutability.
+ *
+ * An evaluation context that is mutable but in a limited way, that is, not allowing the modifications
+ * of variables whose changes might cause issues outside of the function. An example of this would be
+ * the modification of the [numberImplementation], which would cause code paths such as the parsing
+ * of NumberNodes to produce a different type of number than if the function did not run, whcih is unacceptable.
+ *
+ * @param parent the parent of this context.
+ * @param numberImplementation the number implementation used in this context.
+ * @param abacus the abacus instance used.
+ */
+abstract class PluginEvaluationContext(parent: EvaluationContext? = null,
+                                       numberImplementation: NumberImplementation? = null,
+                                       abacus: Abacus? = null) :
+        EvaluationContext(parent, numberImplementation, abacus) {
+
+    /**
+     * Sets a variable to a certain [value].
+     * @param name the name of the variable.
+     * @param value the value of the variable.
+     */
+    fun setVariable(name: String, value: NumberInterface) {
+        variableMap[name] = value
+    }
+
+    /**
+     * Set a definition to a certain [value].
+     * @param name the name of the definition.
+     * @param value the value of the definition.
+     */
+    fun setDefinition(name: String, value: TreeNode) {
+        definitionMap[name] = value
+    }
+
+    /**
+     * Clears the variables defined in this context.
+     */
+    fun clearVariables(){
+        variableMap.clear()
+    }
+
+    /**
+     * Clears the definitions defined in this context.
+     */
+    fun clearDefinitions(){
+        definitionMap.clear()
+    }
+
+
+}

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

@@ -1,6 +1,7 @@
 package org.nwapw.abacus.function
 
 import org.nwapw.abacus.context.MutableEvaluationContext
+import org.nwapw.abacus.context.PluginEvaluationContext
 import org.nwapw.abacus.exception.DomainException
 
 /**
@@ -18,7 +19,7 @@ interface Applicable<in T : Any, out O : Any> {
      * @param params the parameter array to verify for compatibility.
      * @return whether the array can be used with applyInternal.
      */
-    fun matchesParams(context: MutableEvaluationContext, params: Array<out T>): Boolean
+    fun matchesParams(context: PluginEvaluationContext, params: Array<out T>): Boolean
 
     /**
      * Applies the applicable object to the given parameters,
@@ -26,7 +27,7 @@ interface Applicable<in T : Any, out O : Any> {
      * @param params the parameters to apply to.
      * @return the result of the application.
      */
-    fun applyInternal(context: MutableEvaluationContext, params: Array<out T>): O
+    fun applyInternal(context: PluginEvaluationContext, params: Array<out T>): O
 
     /**
      * If the parameters can be used with this applicable, returns
@@ -35,7 +36,7 @@ interface Applicable<in T : Any, out O : Any> {
      * @param params the parameters to apply to.
      * @return the result of the operation, or null if parameters do not match.
      */
-    fun apply(context: MutableEvaluationContext, vararg params: T): O {
+    fun apply(context: PluginEvaluationContext, vararg params: T): O {
         if (!matchesParams(context, params))
             throw DomainException("parameters do not match function requirements.")
         return applyInternal(context, params)

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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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
 
 /**
@@ -13,9 +13,9 @@ import org.nwapw.abacus.number.NumberInterface
  */
 class OperatorAdd: NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params[0] + params[1]
 
 }

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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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.*
 
@@ -14,12 +14,12 @@ import org.nwapw.abacus.plugin.standard.StandardPlugin.*
  */
 class OperatorCaret: NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 2) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2
                     && !(params[0].signum() == 0 && params[1].signum() == 0)
                     && !(params[0].signum() == -1 && !params[1].isInteger())
 
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
         val implementation = context.inheritedNumberImplementation
         if (params[0].signum() == 0)
             return implementation.instanceForString("0")

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

@@ -1,6 +1,6 @@
 package org.nwapw.abacus.plugin.standard.operator
 
-import org.nwapw.abacus.context.MutableEvaluationContext
+import org.nwapw.abacus.context.PluginEvaluationContext
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
 import org.nwapw.abacus.function.interfaces.TreeValueOperator
@@ -16,13 +16,13 @@ import org.nwapw.abacus.tree.nodes.VariableNode
  */
 class OperatorDefine: TreeValueOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out TreeNode>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out TreeNode>) =
             params.size == 2 && params[0] is VariableNode
 
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out TreeNode>): NumberInterface {
+    override fun applyInternal(context: PluginEvaluationContext, 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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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
 
 /**
@@ -13,9 +13,9 @@ import org.nwapw.abacus.number.NumberInterface
  */
 class OperatorDivide: NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params[0] / params[1]
 
 }

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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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
 
 /**
@@ -13,12 +13,12 @@ import org.nwapw.abacus.number.NumberInterface
  */
 class OperatorFactorial: NumberOperator(OperatorAssociativity.LEFT, OperatorType.UNARY_POSTFIX, 0) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
         params.size == 1
                 && params[0].isInteger()
                 && params[0].signum() >= 0
 
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
         val implementation = context.inheritedNumberImplementation
         val one = implementation.instanceForString("1")
         if (params[0].signum() == 0) {

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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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
 
 /**
@@ -13,9 +13,9 @@ import org.nwapw.abacus.number.NumberInterface
  */
 class OperatorMultiply: NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params[0] * params[1]
 
 }

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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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.
@@ -15,11 +16,11 @@ 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>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2 && params[0].isInteger()
                     && params[1].isInteger()
 
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun applyInternal(context: PluginEvaluationContext, 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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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
 
 /**
@@ -13,10 +13,10 @@ import org.nwapw.abacus.number.NumberInterface
  */
 class OperatorNegate: NumberOperator(OperatorAssociativity.LEFT, OperatorType.UNARY_PREFIX, 0) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 1
 
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             -params[0]
 
 }

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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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
 
 /**
@@ -14,11 +14,11 @@ import org.nwapw.abacus.number.NumberInterface
  */
 class OperatorNpr: NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2 && params[0].isInteger()
                     && params[1].isInteger()
 
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>): NumberInterface {
         val implementation = context.inheritedNumberImplementation
         if (params[0] < params[1] ||
                 params[0].signum() < 0 ||

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

@@ -1,6 +1,6 @@
 package org.nwapw.abacus.plugin.standard.operator
 
-import org.nwapw.abacus.context.MutableEvaluationContext
+import org.nwapw.abacus.context.PluginEvaluationContext
 import org.nwapw.abacus.function.OperatorAssociativity
 import org.nwapw.abacus.function.OperatorType
 import org.nwapw.abacus.function.interfaces.TreeValueOperator
@@ -15,12 +15,12 @@ import org.nwapw.abacus.tree.nodes.VariableNode
  */
 class OperatorSet: TreeValueOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out TreeNode>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out TreeNode>) =
             params.size == 2 && params[0] is VariableNode
 
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out TreeNode>): NumberInterface {
+    override fun applyInternal(context: PluginEvaluationContext, 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.context.PluginEvaluationContext
-import org.nwapw.abacus.function.interfaces.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
 
 /**
@@ -13,9 +13,9 @@ import org.nwapw.abacus.number.NumberInterface
  */
 class OperatorSubtract: NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
 
-    override fun matchesParams(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun matchesParams(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params.size == 2
-    override fun applyInternal(context: MutableEvaluationContext, params: Array<out NumberInterface>) =
+    override fun applyInternal(context: PluginEvaluationContext, params: Array<out NumberInterface>) =
             params[0] - params[1]
 
 }

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

@@ -1,67 +0,0 @@
-package org.nwapw.abacus.tree.standard
-
-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
-import org.nwapw.abacus.tree.Reducer
-import org.nwapw.abacus.tree.nodes.*
-
-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 NumberFunctionNode -> {
-                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/test/java/org/nwapw/abacus/tests/RangeTests.java

@@ -6,8 +6,8 @@ import org.junit.Test;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.config.Configuration;
 import org.nwapw.abacus.number.promotion.PromotionFunction;
-import org.nwapw.abacus.number.standard.NaiveNumber;
 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;
 

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

@@ -1,19 +1,22 @@
 package org.nwapw.abacus.tests;
 
+import org.jetbrains.annotations.NotNull;
 import org.junit.Assert;
 import org.junit.BeforeClass;
 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.context.PluginEvaluationContext;
+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.standard.LexerTokenizer;
-import org.nwapw.abacus.plugin.Plugin;
 import org.nwapw.abacus.parsing.standard.TokenType;
+import org.nwapw.abacus.plugin.Plugin;
 
 import java.util.List;
 
@@ -23,12 +26,12 @@ public class TokenizerTests {
     private static LexerTokenizer lexerTokenizer = new LexerTokenizer();
     private static NumberFunction subtractFunction = new NumberFunction() {
         @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+        public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
             return params.length == 2;
         }
 
         @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+        public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
             return params[0].subtract(params[1]);
         }
     };
@@ -39,12 +42,12 @@ public class TokenizerTests {
                     0) {
 
                 @Override
-                public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+                public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
                     return true;
                 }
 
                 @Override
-                public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+                public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
                     return subtractFunction.apply(context, params);
                 }
             });
@@ -52,12 +55,12 @@ public class TokenizerTests {
                     0) {
 
                 @Override
-                public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
+                public boolean matchesParams(PluginEvaluationContext context, NumberInterface[] params) {
                     return true;
                 }
 
                 @Override
-                public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
+                public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
                     return subtractFunction.apply(context, params);
                 }
             });

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

@@ -359,10 +359,13 @@ public class AbacusController implements PluginListener {
             if(documentationInstance == null)
                 documentationInstance = new Documentation(name, "", "", "", DocumentationType.FUNCTION);
             return documentationInstance;
-        })
+        }).collect(Collectors.toCollection(ArrayList::new)));
-                .collect(Collectors.toCollection(ArrayList::new)));
+        functionList.addAll(manager.getAllTreeValueFunctions().stream().map(name -> {
-        functionList.addAll(manager.getAllTreeValueFunctions().stream().map(name -> pluginManager.documentationFor(name, DocumentationType.TREE_VALUE_FUNCTION))
+            Documentation documentationInstance = pluginManager.documentationFor(name, DocumentationType.TREE_VALUE_FUNCTION);
-                .collect(Collectors.toCollection(ArrayList::new)));
+            if(documentationInstance == null)
+                documentationInstance = new Documentation(name, "", "", "", DocumentationType.TREE_VALUE_FUNCTION);
+            return documentationInstance;
+        }).collect(Collectors.toCollection(ArrayList::new)));
         functionList.sort(Comparator.comparing(Documentation::getCodeName));
     }