1 files changed, 8 insertions, 1 deletions
diff --git a/src/main/java/org/zwobble/couscous/values/StringValue.java b/src/main/java/org/zwobble/couscous/values/StringValue.java
index 0e3f626..3a1a13d 100644
--- a/src/main/java/org/zwobble/couscous/values/StringValue.java
+++ b/src/main/java/org/zwobble/couscous/values/StringValue.java
@@ -1,15 +1,22 @@
 package org.zwobble.couscous.values;
 
+import java.util.List;
+
 import lombok.Value;
+import lombok.val;
 
 @Value
 public class StringValue implements InterpreterValue {
     String value;
 
     @Override
-    public InterpreterValue callMethod(String methodName) {
+    public InterpreterValue callMethod(String methodName, List<InterpreterValue> arguments) {
         if (methodName == "length") {
             return new IntegerValue(value.length());
+        } else if (methodName == "substring") {
+            val startIndex = (IntegerValue)arguments.get(0);
+            val endIndex = (IntegerValue)arguments.get(1);
+            return new StringValue(value.substring(startIndex.getValue(), endIndex.getValue()));
         } else {
             throw new UnsupportedOperationException();
         }