From 0c12bb7771537380a22083a8d0dd6df46a95bb99 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 6 Oct 2015 17:41:14 +0100
Subject: Throw error if field is unbound

---
 .../zwobble/couscous/interpreter/UnboundField.java   | 12 ++++++++++++
 .../interpreter/values/ObjectInterpreterValue.java   |  4 +++-
 .../couscous/tests/interpreter/EvaluatorTests.java   | 20 ++++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/org/zwobble/couscous/interpreter/UnboundField.java

(limited to 'src')

diff --git a/src/main/java/org/zwobble/couscous/interpreter/UnboundField.java b/src/main/java/org/zwobble/couscous/interpreter/UnboundField.java
new file mode 100644
index 0000000..2efca06
--- /dev/null
+++ b/src/main/java/org/zwobble/couscous/interpreter/UnboundField.java
@@ -0,0 +1,12 @@
+package org.zwobble.couscous.interpreter;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+
+@Value
+@EqualsAndHashCode(callSuper=false)
+public class UnboundField extends InterpreterException {
+    private static final long serialVersionUID = 1L;
+
+    String fieldName;
+}
diff --git a/src/main/java/org/zwobble/couscous/interpreter/values/ObjectInterpreterValue.java b/src/main/java/org/zwobble/couscous/interpreter/values/ObjectInterpreterValue.java
index b6a1e87..03e8061 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/values/ObjectInterpreterValue.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/values/ObjectInterpreterValue.java
@@ -6,6 +6,7 @@ import java.util.Optional;
 
 import org.zwobble.couscous.interpreter.InterpreterTypes;
 import org.zwobble.couscous.interpreter.NoSuchField;
+import org.zwobble.couscous.interpreter.UnboundField;
 import org.zwobble.couscous.values.PrimitiveValue;
 
 import lombok.val;
@@ -31,10 +32,11 @@ public class ObjectInterpreterValue implements InterpreterValue {
 
     @Override
     public InterpreterValue getField(String fieldName) {
+        type.getField(fieldName).orElseThrow(() -> new NoSuchField(fieldName));
         if (fields.containsKey(fieldName)) {
             return fields.get(fieldName);            
         } else {
-            throw new NoSuchField(fieldName);
+            throw new UnboundField(fieldName);
         }
     }
 
diff --git a/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java b/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java
index 0f96fe7..e8875ae 100644
--- a/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java
@@ -14,6 +14,7 @@ import org.zwobble.couscous.interpreter.Environment;
 import org.zwobble.couscous.interpreter.NoSuchField;
 import org.zwobble.couscous.interpreter.NoSuchMethod;
 import org.zwobble.couscous.interpreter.StackFrameBuilder;
+import org.zwobble.couscous.interpreter.UnboundField;
 import org.zwobble.couscous.interpreter.UnexpectedValueType;
 import org.zwobble.couscous.interpreter.WrongNumberOfArguments;
 import org.zwobble.couscous.interpreter.values.IntegerInterpreterValue;
@@ -133,6 +134,25 @@ public class EvaluatorTests extends BackendEvalTests {
         assertEquals(new NoSuchField("value"), exception);
     }
     
+    @Test
+    public void cannotGetValueOfUnbounddField() {
+        val classNode = ClassNode.builder("com.example.Example")
+            .field("value", IntegerValue.REF)
+            .build();
+        
+        val exception = assertThrows(UnboundField.class,
+            () -> evalExpression(
+                asList(classNode),
+                fieldAccess(
+                    constructorCall(
+                        classNode.getName(),
+                        asList()),
+                    "value",
+                    IntegerValue.REF)));
+        
+        assertEquals(new UnboundField("value"), exception);
+    }
+    
     @Test
     public void cannotSetValueOfUndeclaredField() {
         val classNode = ClassNode.builder("com.example.Example")
-- 
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