Throw error if field is unbound

2 files changed, 15 insertions, 1 deletions

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);
         }
     }