From fec7b703498ff1ed0b0d31ed602e0ba9459985f1 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 29 Sep 2015 20:23:15 +0100
Subject: Extract Environment class

---
 .../zwobble/couscous/interpreter/Environment.java   | 21 +++++++++++++++++++++
 .../org/zwobble/couscous/interpreter/Evaluator.java | 12 +++++-------
 .../zwobble/couscous/interpreter/Interpreter.java   | 10 +++++-----
 3 files changed, 31 insertions(+), 12 deletions(-)
 create mode 100644 src/main/java/org/zwobble/couscous/interpreter/Environment.java

(limited to 'src')

diff --git a/src/main/java/org/zwobble/couscous/interpreter/Environment.java b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
new file mode 100644
index 0000000..ef91916
--- /dev/null
+++ b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
@@ -0,0 +1,21 @@
+package org.zwobble.couscous.interpreter;
+
+import java.util.Map;
+
+import org.zwobble.couscous.values.InterpreterValue;
+
+public class Environment {
+    private Map<Integer, InterpreterValue> stackFrame;
+
+    public Environment(Map<Integer, InterpreterValue> stackFrame) {
+        this.stackFrame = stackFrame;
+    }
+
+    public InterpreterValue get(int referentId) {
+        return stackFrame.get(referentId);
+    }
+
+    public void put(int referentId, InterpreterValue value) {
+        stackFrame.put(referentId, value);
+    }
+}
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
index 033bfb8..02acbe3 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
@@ -1,7 +1,5 @@
 package org.zwobble.couscous.interpreter;
 
-import java.util.Map;
-
 import org.zwobble.couscous.ast.Assignment;
 import org.zwobble.couscous.ast.ExpressionNode;
 import org.zwobble.couscous.ast.LiteralNode;
@@ -12,10 +10,10 @@ import org.zwobble.couscous.values.InterpreterValue;
 import lombok.val;
 
 public class Evaluator implements ExpressionNodeVisitor<InterpreterValue> {
-    private final Map<Integer, InterpreterValue> stackFrame;
+    private final Environment environment;
 
-    public Evaluator(Map<Integer, InterpreterValue> stackFrame) {
-        this.stackFrame = stackFrame;
+    public Evaluator(Environment environment) {
+        this.environment = environment;
     }
     
     public InterpreterValue eval(ExpressionNode expression) {
@@ -29,13 +27,13 @@ public class Evaluator implements ExpressionNodeVisitor<InterpreterValue> {
 
     @Override
     public InterpreterValue visit(VariableReferenceNode variableReference) {
-        return stackFrame.get(variableReference.getReferentId());
+        return environment.get(variableReference.getReferentId());
     }
 
     @Override
     public InterpreterValue visit(Assignment assignment) {
         val value = eval(assignment.getValue());
-        stackFrame.put(assignment.getTarget().getReferentId(), value);
+        environment.put(assignment.getTarget().getReferentId(), value);
         return value;
     }
 }
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java b/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java
index 8bf6479..d68f4df 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Interpreter.java
@@ -1,7 +1,6 @@
 package org.zwobble.couscous.interpreter;
 
 import java.util.List;
-import java.util.Map;
 import java.util.Optional;
 import java.util.stream.IntStream;
 
@@ -29,10 +28,10 @@ public class Interpreter {
         val clazz = project.findClass(className);
         val method = find(clazz.getMethods(),
             method -> method.getName().equals(methodName));
-        val stackFrame = buildStackFrame(method, arguments);
+        val environment = buildEnvironment(method, arguments);
         
         for (val statement : method.getBody()) {
-            val result = statement.accept(new Executor(new Evaluator(stackFrame)));
+            val result = statement.accept(new Executor(new Evaluator(environment)));
             if (result.isPresent()) {
                 return result.get();
             }
@@ -40,7 +39,7 @@ public class Interpreter {
         return UNIT;
     }
 
-    private Map<Integer, InterpreterValue> buildStackFrame(
+    private Environment buildEnvironment(
         final MethodNode method,
         List<InterpreterValue> arguments) {
         
@@ -48,11 +47,12 @@ public class Interpreter {
             throw new WrongNumberOfArguments(method.getArguments().size(), arguments.size());
         }
         
-        return IntStream.range(0, method.getArguments().size())
+        val stackFrame = IntStream.range(0, method.getArguments().size())
             .boxed()
             .collect(toMap(
                 index -> method.getArguments().get(index).getId(),
                 index -> arguments.get(index)));
+        return new Environment(stackFrame);
     }
     
     private class Executor implements StatementNodeVisitor<Optional<InterpreterValue>> {
-- 
cgit v1.2.3