Throw exception if assigning value of wrong type

1 files changed, 24 insertions, 8 deletions

diff --git a/src/main/java/org/zwobble/couscous/interpreter/Environment.java b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
index a24bf1c..27e337a 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Environment.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
@@ -1,6 +1,5 @@
 package org.zwobble.couscous.interpreter;
 
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
 
@@ -8,27 +7,36 @@ import org.zwobble.couscous.Project;
 import org.zwobble.couscous.ast.VariableNode;
 import org.zwobble.couscous.values.ConcreteType;
 import org.zwobble.couscous.values.InterpreterValue;
+import org.zwobble.couscous.values.TypeReference;
+
+import static java.util.stream.Collectors.toMap;
+import static org.zwobble.couscous.util.CousCousMaps.mapKeys;
 
 import lombok.val;
 
 public class Environment {
-    private final Map<Integer, Optional<InterpreterValue>> stackFrame;
     private final Project project;
+    private final Map<Integer, Optional<InterpreterValue>> stackFrameValues;
+    private final Map<Integer, TypeReference> stackFrameTypes;
 
-    public Environment(Project project, Map<Integer, Optional<InterpreterValue>> stackFrame) {
+    public Environment(Project project, Map<VariableNode, Optional<InterpreterValue>> stackFrame) {
         this.project = project;
-        this.stackFrame = new HashMap<>(stackFrame);
+        this.stackFrameValues = mapKeys(stackFrame, variable -> variable.getId());
+        this.stackFrameTypes = stackFrame.keySet()
+            .stream()
+            .collect(toMap(variable -> variable.getId(), variable -> variable.getType()));
     }
 
     public InterpreterValue get(int variableId) {
         checkVariableIsInScope(variableId);
-        val value = stackFrame.get(variableId);
+        val value = stackFrameValues.get(variableId);
         return value.orElseThrow(() -> new UnboundVariable(variableId));
     }
 
     public void put(int variableId, InterpreterValue value) {
         checkVariableIsInScope(variableId);
-        stackFrame.put(variableId, Optional.of(value));
+        checkVariableType(variableId, value);
+        stackFrameValues.put(variableId, Optional.of(value));
     }
 
     public void put(VariableNode variable, InterpreterValue value) {
@@ -40,13 +48,21 @@ public class Environment {
         return project.findClass(className);
     }
 
-    public Environment withStackFrame(Map<Integer, Optional<InterpreterValue>> stackFrame) {
+    public Environment withStackFrame(Map<VariableNode, Optional<InterpreterValue>> stackFrame) {
         return new Environment(project, stackFrame);
     }
 
     private void checkVariableIsInScope(int variableId) {
-        if (!stackFrame.containsKey(variableId)) {
+        if (!stackFrameValues.containsKey(variableId)) {
             throw new VariableNotInScope(variableId);
         }
     }
+
+    private void checkVariableType(int variableId, InterpreterValue value) {
+        val variableType = stackFrameTypes.get(variableId);
+        val valueType = value.getType().getReference();
+        if (!variableType.equals(valueType)) {
+            throw new UnexpectedValueType(variableType, valueType);
+        }
+    }
 }