5 files changed, 25 insertions, 1 deletions
diff --git a/src/main/java/org/zwobble/couscous/values/BooleanValue.java b/src/main/java/org/zwobble/couscous/values/BooleanValue.java
index 6d016e6..e6998df 100644
--- a/src/main/java/org/zwobble/couscous/values/BooleanValue.java
+++ b/src/main/java/org/zwobble/couscous/values/BooleanValue.java
@@ -12,4 +12,9 @@ public class BooleanValue implements InterpreterValue {
     public boolean getValue() {
         return value;
     }
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        throw new UnsupportedOperationException();
+    }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/IntegerValue.java b/src/main/java/org/zwobble/couscous/values/IntegerValue.java
index 062d137..2bb28d8 100644
--- a/src/main/java/org/zwobble/couscous/values/IntegerValue.java
+++ b/src/main/java/org/zwobble/couscous/values/IntegerValue.java
@@ -5,4 +5,9 @@ import lombok.Value;
 @Value
 public class IntegerValue implements InterpreterValue {
     int value;
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        throw new UnsupportedOperationException();
+    }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/InterpreterValue.java b/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
index 64b0e91..7ffebbc 100644
--- a/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
+++ b/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
@@ -1,5 +1,5 @@
 package org.zwobble.couscous.values;
 
 public interface InterpreterValue {
-
+    InterpreterValue callMethod(String methodName);
 }
diff --git a/src/main/java/org/zwobble/couscous/values/StringValue.java b/src/main/java/org/zwobble/couscous/values/StringValue.java
index 1478d41..0e3f626 100644
--- a/src/main/java/org/zwobble/couscous/values/StringValue.java
+++ b/src/main/java/org/zwobble/couscous/values/StringValue.java
@@ -5,4 +5,13 @@ import lombok.Value;
 @Value
 public class StringValue implements InterpreterValue {
     String value;
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        if (methodName == "length") {
+            return new IntegerValue(value.length());
+        } else {
+            throw new UnsupportedOperationException();
+        }
+    }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/UnitValue.java b/src/main/java/org/zwobble/couscous/values/UnitValue.java
index 1cf9dc7..45178dd 100644
--- a/src/main/java/org/zwobble/couscous/values/UnitValue.java
+++ b/src/main/java/org/zwobble/couscous/values/UnitValue.java
@@ -8,4 +8,9 @@ public class UnitValue implements InterpreterValue {
     
     private UnitValue() {
     }
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        throw new UnsupportedOperationException();
+    }
 }