From 6358a63af51285fbf8f3285cd3c9c705bab421cd Mon Sep 17 00:00:00 2001
From: josh <josh@45c1a28c-8058-47b2-ae61-ca45b979098e>
Date: Sun, 1 Jun 2008 23:32:58 +0000
Subject: [PATCH] evaluating divide and minus in correct order

git-svn-id: svn://anubis/gvsu@116 45c1a28c-8058-47b2-ae61-ca45b979098e
---
 .../gvsu/cs675/bottomup/Evaluator.java        | 37 ++++++++++---------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/cs675/bottomup/jholtrop/gvsu/cs675/bottomup/Evaluator.java b/cs675/bottomup/jholtrop/gvsu/cs675/bottomup/Evaluator.java
index 26a6a4c..0a2356c 100644
--- a/cs675/bottomup/jholtrop/gvsu/cs675/bottomup/Evaluator.java
+++ b/cs675/bottomup/jholtrop/gvsu/cs675/bottomup/Evaluator.java
@@ -6,7 +6,7 @@ import jholtrop.gvsu.cs675.bottomup.node.*;
 import jholtrop.gvsu.cs675.bottomup.lexer.Lexer;
 import jholtrop.gvsu.cs675.bottomup.parser.Parser;
 import java.io.*;
-import java.util.HashMap;
+import java.util.Stack;
 
 public class Evaluator extends DepthFirstAdapter
 {
@@ -20,7 +20,9 @@ public class Evaluator extends DepthFirstAdapter
 
             Start tree = p.parse();
 
-            tree.apply(new Evaluator());
+            Evaluator e = new Evaluator();
+            tree.apply(e);
+            System.out.println("Result: " + e.getResult());
         }
         catch (Exception e)
         {
@@ -28,38 +30,39 @@ public class Evaluator extends DepthFirstAdapter
         }
     }
 
-    private HashMap<Node, Double> m_exprValues = new HashMap<Node, Double>();
+    private Stack<Double> m_exprValues = new Stack<Double>();
 
-    private double getNumValue(TNumber num)
+    public double getResult()
     {
-        return Double.parseDouble(num.getText());
+        return m_exprValues.peek();
     }
 
     public void outAAdditionExpr(AAdditionExpr e)
     {
-        Double result =
-            m_exprValues.get(e.getExpr()) + m_exprValues.get(e.getTerm());
-        m_exprValues.put(e, new Double(result));
+        m_exprValues.push(m_exprValues.pop() + m_exprValues.pop());
     }
 
     public void outASubtractionExpr(ASubtractionExpr e)
     {
-        Double result =
-            m_exprValues.get(e.getExpr()) - m_exprValues.get(e.getTerm());
-        m_exprValues.put(e, new Double(result));
+        double b = m_exprValues.pop();
+        double a = m_exprValues.pop();
+        m_exprValues.push(a - b);
     }
 
     public void outAMultiplicationTerm(AMultiplicationTerm e)
     {
-        Double result =
-            m_exprValues.get(e.getTerm()) * m_exprValues.get(e.getFactor());
-        m_exprValues.put(e, new Double(result));
+        m_exprValues.push(m_exprValues.pop() * m_exprValues.pop());
     }
 
     public void outADivisionTerm(ADivisionTerm e)
     {
-        Double result =
-            m_exprValues.get(e.getTerm()) / m_exprValues.get(e.getFactor());
-        m_exprValues.put(e, new Double(result));
+        double b = m_exprValues.pop();
+        double a = m_exprValues.pop();
+        m_exprValues.push(a / b);
+    }
+
+    public void caseTNumber(TNumber n)
+    {
+        m_exprValues.push(Double.parseDouble(n.getText()));
     }
 }