From ef1890f24da6ebd80f64d8b1d6c5249d0c25684b Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Wed, 6 Sep 2017 22:22:15 -0700
Subject: [PATCH] Switch Abacus to returning an EvaluationResult with the
 context.

---
 .../main/kotlin/org/nwapw/abacus/Abacus.kt    | 19 +++++++++++++++++--
 .../org/nwapw/abacus/tree/EvaluationResult.kt |  7 +++++++
 .../nwapw/abacus/tests/CalculationTests.java  |  2 +-
 .../org/nwapw/abacus/fx/AbacusController.java |  5 ++++-
 4 files changed, 29 insertions(+), 4 deletions(-)
 create mode 100644 core/src/main/kotlin/org/nwapw/abacus/tree/EvaluationResult.kt

diff --git a/core/src/main/kotlin/org/nwapw/abacus/Abacus.kt b/core/src/main/kotlin/org/nwapw/abacus/Abacus.kt
index b2fbfa5..c0dfe12 100644
--- a/core/src/main/kotlin/org/nwapw/abacus/Abacus.kt
+++ b/core/src/main/kotlin/org/nwapw/abacus/Abacus.kt
@@ -11,6 +11,7 @@ import org.nwapw.abacus.parsing.TreeBuilder
 import org.nwapw.abacus.plugin.NumberImplementation
 import org.nwapw.abacus.plugin.PluginManager
 import org.nwapw.abacus.plugin.StandardPlugin
+import org.nwapw.abacus.tree.EvaluationResult
 import org.nwapw.abacus.tree.NumberReducer
 import org.nwapw.abacus.tree.TreeNode
 import org.nwapw.abacus.variables.VariableDatabase
@@ -63,6 +64,9 @@ class Abacus(val configuration: Configuration) {
         pluginManager.addListener(promotionManager)
     }
 
+    /**
+     * Reloads the Abacus core.
+     */
     fun reload(){
         pluginManager.reload()
         with(mutableContext) {
@@ -71,6 +75,14 @@ class Abacus(val configuration: Configuration) {
             clearDefinitions()
         }
     }
+    /**
+     * Merges the current context with the provided one, updating
+     * variables and the like.
+     * @param context the context to apply.
+     */
+    fun applyToContext(context: ReductionContext){
+        mutableContext.apply(context)
+    }
     /**
      * Parses a string into a tree structure using the main
      * tree builder.
@@ -86,7 +98,10 @@ class Abacus(val configuration: Configuration) {
      * @param tree the tree to reduce, must not be null.
      * @return the resulting number, or null of the reduction failed.
      */
-    fun evaluateTree(tree: TreeNode): NumberInterface? =
-            tree.reduce(NumberReducer(this, context))
+    fun evaluateTree(tree: TreeNode): EvaluationResult {
+        val newReducer = NumberReducer(this, context)
+        val evaluationValue = tree.reduce(newReducer)
+        return EvaluationResult(evaluationValue, newReducer.context)
+    }
 
 }
\ No newline at end of file
diff --git a/core/src/main/kotlin/org/nwapw/abacus/tree/EvaluationResult.kt b/core/src/main/kotlin/org/nwapw/abacus/tree/EvaluationResult.kt
new file mode 100644
index 0000000..89bde63
--- /dev/null
+++ b/core/src/main/kotlin/org/nwapw/abacus/tree/EvaluationResult.kt
@@ -0,0 +1,7 @@
+package org.nwapw.abacus.tree
+
+import org.nwapw.abacus.context.MutableReductionContext
+import org.nwapw.abacus.number.NumberInterface
+import org.nwapw.abacus.plugin.NumberImplementation
+
+data class EvaluationResult(val value: NumberInterface?, val resultingContext: MutableReductionContext)
\ No newline at end of file
diff --git a/core/src/test/java/org/nwapw/abacus/tests/CalculationTests.java b/core/src/test/java/org/nwapw/abacus/tests/CalculationTests.java
index 1818090..0a00289 100755
--- a/core/src/test/java/org/nwapw/abacus/tests/CalculationTests.java
+++ b/core/src/test/java/org/nwapw/abacus/tests/CalculationTests.java
@@ -24,7 +24,7 @@ public class CalculationTests {
         TreeNode parsedTree = abacus.parseString(input);
         Assert.assertNotNull(parsedTree);
         Assert.assertEquals(parsedTree.toString(), parseOutput);
-        NumberInterface result = abacus.evaluateTree(parsedTree);
+        NumberInterface result = abacus.evaluateTree(parsedTree).getValue();
         Assert.assertNotNull(result);
         Assert.assertTrue(result.toString().startsWith(output));
     }
diff --git a/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index 74527a1..435da06 100644
--- a/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -20,6 +20,7 @@ import org.nwapw.abacus.plugin.ClassFinder;
 import org.nwapw.abacus.plugin.PluginListener;
 import org.nwapw.abacus.plugin.PluginManager;
 import org.nwapw.abacus.plugin.StandardPlugin;
+import org.nwapw.abacus.tree.EvaluationResult;
 import org.nwapw.abacus.tree.TreeNode;
 
 import java.io.File;
@@ -144,12 +145,14 @@ public class AbacusController implements PluginListener {
                 if (constructedTree == null) {
                     return ERR_SYNTAX;
                 }
-                NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
+                EvaluationResult result = abacus.evaluateTree(constructedTree);
+                NumberInterface evaluatedNumber = result.getValue();
                 if (evaluatedNumber == null) {
                     return ERR_EVAL;
                 }
                 String resultingString = evaluatedNumber.toString();
                 historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), resultingString));
+                abacus.applyToContext(result.getResultingContext());
                 return resultingString;
             } catch (ComputationInterruptedException exception) {
                 return ERR_STOP;