diff --git a/src/JohnnyScript.java b/src/JohnnyScript.java
index f4ac742..fcea1a5 100644
--- a/src/JohnnyScript.java
+++ b/src/JohnnyScript.java
@@ -168,20 +168,38 @@ class RamCode {
 
     private ArrayList<String> code;
     private Map<String, Integer> variables;
+    private Map<String, Integer> varLoc;
 
     RamCode() {
         code = new ArrayList<>();
         variables = new LinkedHashMap<>();
+        varLoc = new LinkedHashMap<>();
     }
 
-    public void addCode(String input) {
+    void addCode(String input) {
         code.add(input);
     }
 
-    public void addVar(String name, int value) throws DuplicateVariableException {
+    void addVar(String name, int value) throws DuplicateVariableException {
         if (variables.containsKey(name)) {
             throw new DuplicateVariableException("Variable cannot be defined twice: " + name);
-        } else variables.put(name, value);
+        } else {
+            variables.put(name, value);
+            varLoc.put(name, variables.size());
+        }
+    }
+
+    void addVarRef(String input) throws VariableNotInitializedException {
+        String[] parts = input.split(" ");
+        assert parts.length == 2;
+        assert parts[1].contains("#");
+        String var = parts[1].replace("#","");
+        if (!variables.containsKey(var)) {
+            throw new VariableNotInitializedException("Variable has not been initialized: " + var);
+        } else {
+            int line = varLoc.get(var);
+            code.add(parts[0] + String.format("%03d",line));
+        }
     }
 
     private List<String> initializeZeros(List<String> code) {
@@ -240,3 +258,10 @@ class DuplicateVariableException extends Exception {
 
     DuplicateVariableException(String message) {super(message);}
 }
+
+class VariableNotInitializedException extends Exception {
+
+    VariableNotInitializedException(String message) {
+        super(message);
+    }
+}
diff --git a/test/RamCodeTest.java b/test/RamCodeTest.java
index ff07826..001c864 100644
--- a/test/RamCodeTest.java
+++ b/test/RamCodeTest.java
@@ -20,4 +20,63 @@ public void testInitialize() throws Exception {
             assertEquals("000",codeList.get(i));
         }
     }
+
+    @Test
+    public void testAddCode() throws Exception {
+        RamCode code = new RamCode();
+        code.addCode(JohnnyScript.Codes.ADD.codeOrdinal + "001");
+        List codeList = code.getCode();
+
+        assertEquals(JohnnyScript.Codes.JMP.codeOrdinal + "001",codeList.get(0));
+        assertEquals(JohnnyScript.Codes.ADD.codeOrdinal + "001",codeList.get(1));
+
+        for (int i = 2; i < 1000; i++) {
+            assertEquals("000",codeList.get(i));
+        }
+    }
+
+    @Test
+    public void testAddVar() throws Exception {
+        RamCode code = new RamCode();
+        code.addVar("tst",5);
+
+        List codeList = code.getCode();
+
+        assertEquals(JohnnyScript.Codes.JMP.codeOrdinal + "002",codeList.get(0));
+        assertEquals("005",codeList.get(1));
+
+        for (int i = 2; i < 1000; i++) {
+            assertEquals("000",codeList.get(i));
+        }
+    }
+
+    @Test(expected = VariableNotInitializedException.class)
+    public void testAddVarRefWithoutInit() throws Exception {
+        RamCode code = new RamCode();
+        code.addVarRef(JohnnyScript.Codes.ADD.codeOrdinal+" #tst");
+    }
+
+    @Test(expected = DuplicateVariableException.class)
+    public void testAddDuplicateVar() throws Exception {
+        RamCode code = new RamCode();
+        code.addVar("tst", 5);
+        code.addVar("tst", 8);
+    }
+
+    @Test
+    public void testAddVarRef() throws Exception {
+        RamCode code = new RamCode();
+        code.addVar("tst",5);
+        code.addVarRef(JohnnyScript.Codes.ADD.codeOrdinal+" #tst");
+
+        List codeList = code.getCode();
+
+        assertEquals(JohnnyScript.Codes.JMP.codeOrdinal + "002",codeList.get(0));
+        assertEquals("005",codeList.get(1));
+        assertEquals(JohnnyScript.Codes.ADD.codeOrdinal+"001",codeList.get(2));
+
+        for (int i = 3; i < 1000; i++) {
+            assertEquals("000",codeList.get(i));
+        }
+    }
 }
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