Merge pull request #53 from DanilaFe/definitions-bugfix

Load definitions after Abacus finishes loading.

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

@@ -1,6 +1,8 @@
 package org.nwapw.abacus.plugin.standard;
 
+import org.jetbrains.annotations.NotNull;
 import org.nwapw.abacus.context.MutableEvaluationContext;
+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;
@@ -119,12 +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())));
         }
     };
@@ -133,12 +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");
@@ -166,10 +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).
@@ -214,12 +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())));
         }
     };
@@ -232,12 +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"));
         }
     };
@@ -247,12 +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;
@@ -285,12 +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"));
@@ -310,12 +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]));
         }
@@ -325,12 +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]));
         }
     };
@@ -339,12 +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]));
         }
     };
@@ -353,12 +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]));
         }
     };
@@ -367,12 +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]));
         }
     };
@@ -382,13 +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])))};
@@ -416,12 +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));
         }
@@ -432,12 +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);
         }
@@ -448,12 +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);
         }
@@ -464,12 +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()};
@@ -506,12 +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));
         }
@@ -550,7 +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;
@@ -569,7 +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

@@ -63,13 +63,13 @@ class Abacus(val configuration: Configuration) {
      * Reloads the Abacus core.
      */
     fun reload(){
-        pluginManager.reload()
-        with(mutableContext) {
-            numberImplementation = pluginManager.numberImplementationFor(configuration.numberImplementation)
-                    ?: StandardPlugin.IMPLEMENTATION_NAIVE
+        with(mutableContext){
             clearVariables()
             clearDefinitions()
         }
+        pluginManager.reload()
+        mutableContext.numberImplementation = pluginManager.numberImplementationFor(configuration.numberImplementation)
+                ?: StandardPlugin.IMPLEMENTATION_NAIVE
     }
     /**
      * Merges the current context with the provided one, updating

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

@@ -9,14 +9,15 @@ import org.nwapw.abacus.tree.nodes.*
 
 /**
  * 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,
                                abacus: Abacus? = null) :
-        EvaluationContext(parent, numberImplementation, abacus) {
+        PluginEvaluationContext(parent, numberImplementation, abacus) {
 
     override var numberImplementation: NumberImplementation? = super.numberImplementation
     override var abacus: Abacus? = super.abacus
@@ -35,42 +36,11 @@ class MutableEvaluationContext(parent: EvaluationContext? = null,
         }
     }
 
-    /**
-     * 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()
-    }
-
     override fun reduceNode(treeNode: TreeNode, vararg children: Any): NumberInterface {
+        val oldNumberImplementation = numberImplementation
         val abacus = inheritedAbacus
         val promotionManager = abacus.promotionManager
-        return when(treeNode){
+        val toReturn = when(treeNode){
             is NumberNode -> {
                 inheritedNumberImplementation.instanceForString(treeNode.number)
             }
@@ -114,6 +84,8 @@ class MutableEvaluationContext(parent: EvaluationContext? = null,
             }
             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

@@ -1,6 +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.NumberOperator
@@ -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

@@ -1,6 +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.NumberOperator
@@ -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
@@ -16,10 +16,10 @@ 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)

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorDivide.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.NumberOperator
@@ -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

@@ -1,6 +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.NumberOperator
@@ -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

@@ -1,6 +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.NumberOperator
@@ -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

@@ -1,6 +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.NumberOperator
@@ -16,11 +16,11 @@ import org.nwapw.abacus.plugin.standard.StandardPlugin.OP_NPR
  */
 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

@@ -1,6 +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.NumberOperator
@@ -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

@@ -1,6 +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.NumberOperator
@@ -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
@@ -15,10 +15,10 @@ 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)
         context.setVariable(assignTo, value)

core/src/main/kotlin/org/nwapw/abacus/plugin/standard/operator/OperatorSubtract.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.NumberOperator
@@ -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/test/java/org/nwapw/abacus/tests/TokenizerTests.java

@@ -1,11 +1,13 @@
 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.context.PluginEvaluationContext;
 import org.nwapw.abacus.function.OperatorAssociativity;
 import org.nwapw.abacus.function.OperatorType;
 import org.nwapw.abacus.function.interfaces.NumberFunction;
@@ -24,12 +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]);
         }
     };
@@ -40,12 +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) {
+                @Override
+                public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
                     return subtractFunction.apply(context, params);
                 }
             });
@@ -53,12 +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) {
+                @Override
+                public NumberInterface applyInternal(PluginEvaluationContext context, NumberInterface[] params) {
                     return subtractFunction.apply(context, params);
                 }
             });

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

@@ -26,7 +26,7 @@ public class AbacusApplication extends Application {
         FXMLLoader loader = new FXMLLoader(getClass().getResource("/abacus.fxml"));
         Parent parent = loader.load();
         controller = loader.getController();
-        Scene mainScene = new Scene(parent, 320, 480);
+        Scene mainScene = new Scene(parent, 420, 520);
         primaryStage.setScene(mainScene);
         primaryStage.setTitle("Abacus");
         primaryStage.show();

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

@@ -8,6 +8,7 @@ import javafx.fxml.FXML;
 import javafx.scene.control.*;
 import javafx.scene.control.cell.CheckBoxListCell;
 import javafx.scene.text.Text;
+import javafx.stage.FileChooser;
 import javafx.util.Callback;
 import javafx.util.StringConverter;
 import org.nwapw.abacus.Abacus;
@@ -23,9 +24,12 @@ import org.nwapw.abacus.EvaluationResult;
 import org.nwapw.abacus.tree.nodes.TreeNode;
 
 import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Comparator;
+import java.util.Scanner;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -69,6 +73,7 @@ public class AbacusController implements PluginListener {
      * Constant string that is displayed if the calculations are interrupted by an exception.
      */
     private static final String ERR_EXCEPTION = "Exception Thrown";
+    private static final String ERR_DEFINITION = "Definition Error";
     @FXML
     private TabPane coreTabPane;
     @FXML
@@ -103,6 +108,8 @@ public class AbacusController implements PluginListener {
     private ListView<Documentation> functionListView;
     @FXML
     private TextField functionListSearchField;
+    @FXML
+    private ListView<String> definitionFilesView;
 
     /**
      * The list of history entries, created by the users.
@@ -128,6 +135,10 @@ public class AbacusController implements PluginListener {
      * The filtered list displayed to the user.
      */
     private FilteredList<Documentation> functionFilter;
+    /**
+     * The list of definition files to be loaded.
+     */
+    private ObservableList<String> definitionFiles;
 
     /**
      * The abacus instance used for changing the plugin configuration.
@@ -251,6 +262,9 @@ public class AbacusController implements PluginListener {
             if (oldValue.equals(settingsTab)) alertIfApplyNeeded(true);
         });
 
+        definitionFiles = FXCollections.observableArrayList();
+        definitionFilesView.setItems(definitionFiles);
+
         abacus = new Abacus(new ExtendedConfiguration(CONFIG_FILE));
         PluginManager abacusPluginManager = abacus.getPluginManager();
         abacusPluginManager.addListener(this);
@@ -304,6 +318,25 @@ public class AbacusController implements PluginListener {
         reloadAlertShown = false;
     }
 
+    private void loadDefinitionFile(String fileName){
+        File definitionFile = new File(fileName);
+        if(!definitionFile.exists()) return;
+        try {
+            FileReader fileReader = new FileReader(definitionFile);
+            Scanner scanner = new Scanner(fileReader);
+            while(scanner.hasNext()){
+                EvaluationResult result = abacus.evaluateTree(abacus.parseString(scanner.nextLine()));
+                abacus.applyToContext(result.getResultingContext());
+            }
+        } catch (AbacusException abacusError) {
+            outputText.setText(ERR_DEFINITION + " (" + abacusError.getMessage() + ")");
+            abacusError.printStackTrace();
+        } catch (RuntimeException runtime) {
+            outputText.setText(ERR_DEFINITION + " (" + ERR_EXCEPTION + ")");
+            runtime.printStackTrace();
+        } catch (FileNotFoundException ignored) {}
+    }
+
     @FXML
     public void performScan() {
         PluginManager abacusPluginManager = abacus.getPluginManager();
@@ -314,34 +347,62 @@ public class AbacusController implements PluginListener {
         } catch (IOException | ClassNotFoundException e) {
             e.printStackTrace();
         }
-        abacus.reload();
+        reloadAbacus();
     }
 
     @FXML
     public void performReload() {
         alertIfApplyNeeded(true);
-        abacus.reload();
+        reloadAbacus();
     }
 
     @FXML
     public void performSave() {
-        Configuration configuration = abacus.getConfiguration();
+        ExtendedConfiguration configuration = (ExtendedConfiguration) abacus.getConfiguration();
         configuration.setNumberImplementation(numberImplementationBox.getSelectionModel().getSelectedItem());
         Set<String> disabledPlugins = configuration.getDisabledPlugins();
         disabledPlugins.clear();
         for (ToggleablePlugin pluginEntry : enabledPlugins) {
             if (!pluginEntry.isEnabled()) disabledPlugins.add(pluginEntry.getClassName());
         }
+        Set<String> abacusDefinitionFiles = configuration.getDefinitionFiles();
+        abacusDefinitionFiles.clear();
+        abacusDefinitionFiles.addAll(definitionFiles);
         if (computationLimitField.getText().matches("\\d*(\\.\\d+)?") && computationLimitField.getText().length() != 0)
-            ((ExtendedConfiguration) configuration).setComputationDelay(Double.parseDouble(computationLimitField.getText()));
-        ((ExtendedConfiguration) configuration).saveTo(CONFIG_FILE);
+            configuration.setComputationDelay(Double.parseDouble(computationLimitField.getText()));
+        configuration.saveTo(CONFIG_FILE);
         changesMade = false;
         reloadAlertShown = false;
     }
 
+    @FXML
+    public void performAddDefinitionFile(){
+        FileChooser fileChooser = new FileChooser();
+        fileChooser.setTitle("Add definition file");
+        File selectedFile = fileChooser.showOpenDialog(null);
+        if(selectedFile == null) return;
+        String absolutePath = selectedFile.getAbsolutePath();
+        if(!definitionFiles.contains(absolutePath)) definitionFiles.add(absolutePath);
+        changesMade = true;
+    }
+
+    @FXML
+    public void performRemoveDefinitionFile(){
+        String selectedItem = definitionFilesView.getSelectionModel().getSelectedItem();
+        if(selectedItem != null) definitionFiles.remove(selectedItem);
+        changesMade = true;
+    }
+
+    private void reloadAbacus(){
+        abacus.reload();
+        for(String file : definitionFiles){
+            loadDefinitionFile(file);
+        }
+    }
+
     @Override
     public void onLoad(PluginManager manager) {
-        Configuration configuration = abacus.getConfiguration();
+        ExtendedConfiguration configuration = (ExtendedConfiguration) abacus.getConfiguration();
         Set<String> disabledPlugins = configuration.getDisabledPlugins();
         numberImplementationOptions.addAll(abacus.getPluginManager().getAllNumberImplementations());
         String actualImplementation = configuration.getNumberImplementation();
@@ -367,6 +428,7 @@ public class AbacusController implements PluginListener {
             return documentationInstance;
         }).collect(Collectors.toCollection(ArrayList::new)));
         functionList.sort(Comparator.comparing(Documentation::getCodeName));
+        definitionFiles.addAll(configuration.getDefinitionFiles());
     }
 
     @Override
@@ -374,6 +436,7 @@ public class AbacusController implements PluginListener {
         functionList.clear();
         enabledPlugins.clear();
         numberImplementationOptions.clear();
+        definitionFiles.clear();
     }
 
 }

fx/src/main/kotlin/org/nwapw/abacus/fx/ExtendedConfiguration.kt

@@ -17,8 +17,9 @@ import java.io.File
  * @param disabledPlugins the list of plugins that should be disabled, same as [Configuration.disabledPlugins]
  */
 class ExtendedConfiguration(var computationDelay: Double = 0.0,
-                     implementation: String = "<default>",
-                     disabledPlugins: Array<String> = emptyArray())
+                            definitionFiles: Array<String> = emptyArray(),
+                            implementation: String = "<default>",
+                            disabledPlugins: Array<String> = emptyArray())
     : Configuration(implementation, disabledPlugins) {
 
     companion object {
@@ -27,6 +28,7 @@ class ExtendedConfiguration(var computationDelay: Double = 0.0,
          */
         val DEFAULT_TOML_STRING = """
             computationDelay=0.0
+            definitionFiles=[]
             implementation="naive"
             disabledPlugins=[]
             """
@@ -40,6 +42,11 @@ class ExtendedConfiguration(var computationDelay: Double = 0.0,
         val DEFAULT_TOML_WRITER = TomlWriter()
     }
 
+    /**
+     * The set of files that definitions should be loaded from.
+     */
+    val definitionFiles: MutableSet<String> = mutableSetOf(*definitionFiles)
+
     /**
      * Constructs a new configuration from a file on disk.
      * @param tomlFile the file from disk to load.
@@ -59,6 +66,8 @@ class ExtendedConfiguration(var computationDelay: Double = 0.0,
         numberImplementation = config.numberImplementation
         disabledPlugins.clear()
         disabledPlugins.addAll(config.disabledPlugins)
+        definitionFiles.clear()
+        definitionFiles.addAll(config.definitionFiles)
     }
 
     /**

fx/src/main/resources/abacus.fxml

@@ -47,17 +47,33 @@
                     </padding>
                     <Label text="Number Implementation" GridPane.columnIndex="0" GridPane.rowIndex="0"/>
                     <ComboBox fx:id="numberImplementationBox" GridPane.columnIndex="1" GridPane.rowIndex="0"/>
+
+                    <Label text="Plugins:" GridPane.columnIndex="0" GridPane.rowIndex="1"/>
                     <ListView fx:id="enabledPluginView"
-                              GridPane.rowIndex="1" GridPane.columnIndex="0"
+                              GridPane.rowIndex="2" GridPane.columnIndex="0"
                               GridPane.columnSpan="2" maxHeight="100"/>
-                    <Text GridPane.columnIndex="0" GridPane.rowIndex="2" text="Computation Limit"/>
-                    <TextField fx:id="computationLimitField" GridPane.columnIndex="1" GridPane.rowIndex="2"/>
-                    <FlowPane GridPane.columnIndex="0" GridPane.columnSpan="2" GridPane.rowIndex="3" hgap="10"
+
+                    <Label GridPane.columnIndex="0" GridPane.rowIndex="3" text="Computation Limit"/>
+                    <TextField fx:id="computationLimitField" GridPane.columnIndex="1" GridPane.rowIndex="3"/>
+
+                    <Label text="Definition Files:" GridPane.columnIndex="0" GridPane.rowIndex="4"/>
+                    <ListView fx:id="definitionFilesView"
+                              GridPane.columnIndex="0" GridPane.columnSpan="2"
+                              GridPane.rowIndex="5" maxHeight="100"/>
+                    <FlowPane GridPane.columnIndex="0" GridPane.columnSpan="2" GridPane.rowIndex="6" hgap="10"
                               vgap="10">
-                        <Button text="Save" onAction="#performSave"/>
-                        <Button text="Reload Plugins" onAction="#performReload"/>
-                        <Button text="Apply and Reload" onAction="#performSaveAndReload"/>
-                        <Button text="Scan Plugins" onAction="#performScan"/>
+                        <Button text="Add" onAction="#performAddDefinitionFile"/>
+                        <Button text="Remove" onAction="#performRemoveDefinitionFile"/>
+                    </FlowPane>
+
+                    <Separator GridPane.rowIndex="7"/>
+
+                    <FlowPane GridPane.columnIndex="0" GridPane.columnSpan="2" GridPane.rowIndex="8" hgap="10"
+                              vgap="10">
+                        <Button text="Save Settings" onAction="#performSave"/>
+                        <Button text="Reload Plugins And Definitions" onAction="#performReload"/>
+                        <Button text="Save and Reload" onAction="#performSaveAndReload"/>
+                        <Button text="Reload Plugins From Disk" onAction="#performScan"/>
                     </FlowPane>
                 </GridPane>
             </Tab>