From 4e031ada69e27d9aa518ef00ebf532328ba23e79 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 29 Sep 2015 20:32:35 +0100
Subject: Create separate evaluator tests

---
 src/main/java/org/zwobble/couscous/ast/Assignment.java      |  6 ++++++
 src/main/java/org/zwobble/couscous/ast/LiteralNode.java     |  2 +-
 .../java/org/zwobble/couscous/interpreter/Environment.java  |  3 ++-
 .../java/org/zwobble/couscous/interpreter/Evaluator.java    |  6 +++++-
 .../java/org/zwobble/couscous/interpreter/Interpreter.java  | 13 +++++++------
 5 files changed, 21 insertions(+), 9 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/zwobble/couscous/ast/Assignment.java b/src/main/java/org/zwobble/couscous/ast/Assignment.java
index aa7f89b..d8bdaaf 100644
--- a/src/main/java/org/zwobble/couscous/ast/Assignment.java
+++ b/src/main/java/org/zwobble/couscous/ast/Assignment.java
@@ -2,10 +2,16 @@ package org.zwobble.couscous.ast;
 
 import org.zwobble.couscous.ast.visitors.ExpressionNodeVisitor;
 
+import static org.zwobble.couscous.ast.VariableReferenceNode.reference;
+
 import lombok.Value;
 
 @Value
 public class Assignment implements ExpressionNode {
+    public static Assignment assign(VariableNode target, ExpressionNode value) {
+        return new Assignment(reference(target), value);
+    }
+    
     VariableReferenceNode target;
     ExpressionNode value;
     
diff --git a/src/main/java/org/zwobble/couscous/ast/LiteralNode.java b/src/main/java/org/zwobble/couscous/ast/LiteralNode.java
index 38688d8..594187d 100644
--- a/src/main/java/org/zwobble/couscous/ast/LiteralNode.java
+++ b/src/main/java/org/zwobble/couscous/ast/LiteralNode.java
@@ -9,7 +9,7 @@ import lombok.Value;
 
 @Value
 public class LiteralNode implements ExpressionNode {
-    public static LiteralNode of(String value) {
+    public static LiteralNode literal(String value) {
         return new LiteralNode(new StringValue(value));
     }
     
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Environment.java b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
index ef91916..a3b3871 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Environment.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
@@ -1,5 +1,6 @@
 package org.zwobble.couscous.interpreter;
 
+import java.util.HashMap;
 import java.util.Map;
 
 import org.zwobble.couscous.values.InterpreterValue;
@@ -8,7 +9,7 @@ public class Environment {
     private Map<Integer, InterpreterValue> stackFrame;
 
     public Environment(Map<Integer, InterpreterValue> stackFrame) {
-        this.stackFrame = stackFrame;
+        this.stackFrame = new HashMap<>(stackFrame);
     }
 
     public InterpreterValue get(int referentId) {
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
index 02acbe3..863ccb0 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
@@ -10,9 +10,13 @@ import org.zwobble.couscous.values.InterpreterValue;
 import lombok.val;
 
 public class Evaluator implements ExpressionNodeVisitor<InterpreterValue> {
+    public static InterpreterValue eval(Environment environment, ExpressionNode expression) {
+        return new Evaluator(environment).eval(expression);
+    }
+    
     private final Environment environment;
 
-    public Evaluator(Environment environment) {
+    private Evaluator(Environment environment) {
         this.environment = environment;
     }
     
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java b/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java
index d68f4df..bc82fee 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java
@@ -13,6 +13,7 @@ import org.zwobble.couscous.values.InterpreterValue;
 
 import static com.google.common.collect.Iterables.find;
 import static java.util.stream.Collectors.toMap;
+import static org.zwobble.couscous.interpreter.Evaluator.eval;
 import static org.zwobble.couscous.values.UnitValue.UNIT;
 
 import lombok.val;
@@ -31,7 +32,7 @@ public class Interpreter {
         val environment = buildEnvironment(method, arguments);
         
         for (val statement : method.getBody()) {
-            val result = statement.accept(new Executor(new Evaluator(environment)));
+            val result = statement.accept(new Executor(environment));
             if (result.isPresent()) {
                 return result.get();
             }
@@ -56,20 +57,20 @@ public class Interpreter {
     }
     
     private class Executor implements StatementNodeVisitor<Optional<InterpreterValue>> {
-        private Evaluator evaluator;
+        private Environment environment;
 
-        public Executor(Evaluator evaluator) {
-            this.evaluator = evaluator;
+        public Executor(Environment environment) {
+            this.environment = environment;
         }
         
         @Override
         public Optional<InterpreterValue> visit(ReturnNode returnNode) {
-            return Optional.of(evaluator.eval(returnNode.getValue()));
+            return Optional.of(eval(environment, returnNode.getValue()));
         }
 
         @Override
         public Optional<InterpreterValue> visit(ExpressionStatementNode expressionStatement) {
-            evaluator.eval(expressionStatement.getExpression());
+            eval(environment, expressionStatement.getExpression());
             return Optional.empty();
         }
     }
-- 
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