diff --git a/CMakeLists.txt b/CMakeLists.txt
index e7a50bb..0ad1252 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -271,8 +271,6 @@ target_sources(${EXECUTABLE_NAME} PUBLIC
     "src/sfall_lists.h"
     "src/sfall_opcodes.cc"
     "src/sfall_opcodes.h"
-    "src/sfall_script_value.cc"
-    "src/sfall_script_value.h"
     "src/sfall_arrays.cc"
     "src/sfall_arrays.h"
 )
diff --git a/src/interpreter.cc b/src/interpreter.cc
index 23793ac..e7ad993 100644
--- a/src/interpreter.cc
+++ b/src/interpreter.cc
@@ -3252,7 +3252,7 @@ void* programReturnStackPopPointer(Program* program)
     return programValue.pointerValue;
 }
 
-bool ProgramValue::isEmpty()
+bool ProgramValue::isEmpty() const
 {
     switch (opcode) {
     case VALUE_TYPE_INT:
@@ -3269,19 +3269,19 @@ bool ProgramValue::isEmpty()
 }
 
 // Matches Sfall implementation.
-bool ProgramValue::isInt()
+bool ProgramValue::isInt() const
 {
     return opcode == VALUE_TYPE_INT;
 }
 
 // Matches Sfall implementation.
-bool ProgramValue::isFloat()
+bool ProgramValue::isFloat() const
 {
     return opcode == VALUE_TYPE_FLOAT;
 }
 
 // Matches Sfall implementation.
-float ProgramValue::asFloat()
+float ProgramValue::asFloat() const
 {
     switch (opcode) {
     case VALUE_TYPE_INT:
@@ -3293,4 +3293,77 @@ float ProgramValue::asFloat()
     }
 }
 
+ProgramValue::ProgramValue()
+{
+    opcode = VALUE_TYPE_INT;
+    integerValue = 0;
+}
+ProgramValue::ProgramValue(int value)
+{
+    opcode = VALUE_TYPE_INT;
+    integerValue = value;
+};
+ProgramValue::ProgramValue(Object* value)
+{
+    opcode = VALUE_TYPE_PTR;
+    pointerValue = value;
+};
+
+bool ProgramValue::isPointer() const
+{
+    return opcode == VALUE_TYPE_PTR;
+}
+
+int ProgramValue::asInt() const
+{
+    switch (opcode) {
+    case VALUE_TYPE_INT:
+        return integerValue;
+    case VALUE_TYPE_FLOAT:
+        return static_cast<int>(floatValue);
+    default:
+        return 0;
+    }
+}
+
+bool ProgramValue::operator<(ProgramValue const& other) const
+{
+    if (opcode != other.opcode) {
+        return opcode < other.opcode;
+    }
+
+    switch (opcode) {
+    case VALUE_TYPE_DYNAMIC_STRING:
+    case VALUE_TYPE_STRING:
+    case VALUE_TYPE_PTR:
+        return pointerValue < other.pointerValue;
+    case VALUE_TYPE_INT:
+        return integerValue < other.integerValue;
+    case VALUE_TYPE_FLOAT:
+        return floatValue < other.floatValue;
+    default:
+        throw(std::exception());
+    }
+}
+
+bool ProgramValue::operator==(ProgramValue const& other) const
+{
+    if (opcode != other.opcode) {
+        return false;
+    }
+
+    switch (opcode) {
+    case VALUE_TYPE_DYNAMIC_STRING:
+    case VALUE_TYPE_STRING:
+    case VALUE_TYPE_PTR:
+        return pointerValue == other.pointerValue;
+    case VALUE_TYPE_INT:
+        return integerValue == other.integerValue;
+    case VALUE_TYPE_FLOAT:
+        return floatValue == other.floatValue;
+    default:
+        throw(std::exception());
+    }
+}
+
 } // namespace fallout
diff --git a/src/interpreter.h b/src/interpreter.h
index f84347f..221a24a 100644
--- a/src/interpreter.h
+++ b/src/interpreter.h
@@ -1,6 +1,7 @@
 #ifndef INTERPRETER_H
 #define INTERPRETER_H
 
+#include "object.h"
 #include <setjmp.h>
 
 #include <vector>
@@ -140,7 +141,12 @@ typedef struct Procedure {
     int field_14;
 } Procedure;
 
-typedef struct ProgramValue {
+class ProgramValue {
+public:
+    ProgramValue();
+    ProgramValue(int value);
+    ProgramValue(Object* value);
+
     opcode_t opcode;
     union {
         int integerValue;
@@ -148,11 +154,16 @@ typedef struct ProgramValue {
         void* pointerValue;
     };
 
-    bool isEmpty();
-    bool isInt();
-    bool isFloat();
-    float asFloat();
-} ProgramValue;
+    bool isEmpty() const;
+    bool isInt() const;
+    bool isFloat() const;
+    float asFloat() const;
+    bool isPointer() const;
+    int asInt() const;
+
+    bool operator<(ProgramValue const& other) const;
+    bool operator==(ProgramValue const& other) const;
+};
 
 typedef std::vector<ProgramValue> ProgramStack;
 
diff --git a/src/sfall_arrays.cc b/src/sfall_arrays.cc
index e6c4771..db5e6b0 100644
--- a/src/sfall_arrays.cc
+++ b/src/sfall_arrays.cc
@@ -1,6 +1,5 @@
 #include "sfall_arrays.h"
 #include "interpreter.h"
-#include "sfall_script_value.h"
 
 #include <algorithm>
 #include <cstdint>
@@ -52,15 +51,15 @@ protected:
 public:
     virtual int size() = 0;
     virtual ProgramValue GetArrayKey(int index) = 0;
-    virtual ProgramValue GetArray(const SFallScriptValue& key) = 0;
-    virtual void SetArray(const SFallScriptValue& key, const SFallScriptValue& val, bool allowUnset) = 0;
+    virtual ProgramValue GetArray(const ProgramValue& key) = 0;
+    virtual void SetArray(const ProgramValue& key, const ProgramValue& val, bool allowUnset) = 0;
     virtual void ResizeArray(int newLen) = 0;
 };
 
 class SFallArrayList : public SFallArray {
 private:
     // TODO: SFall copies strings
-    std::vector<SFallScriptValue> values;
+    std::vector<ProgramValue> values;
 
 public:
     SFallArrayList() = delete;
@@ -79,24 +78,24 @@ public:
     ProgramValue GetArrayKey(int index)
     {
         if (index < -1 || index > size()) {
-            return SFallScriptValue(0);
+            return ProgramValue(0);
         };
         if (index == -1) { // special index to indicate if array is associative
-            return SFallScriptValue(0);
+            return ProgramValue(0);
         };
-        return SFallScriptValue(index);
+        return ProgramValue(index);
     }
 
-    ProgramValue GetArray(const SFallScriptValue& key)
+    ProgramValue GetArray(const ProgramValue& key)
     {
         auto element_index = key.asInt();
         if (element_index < 0 || element_index >= size()) {
-            return SFallScriptValue(0);
+            return ProgramValue(0);
         };
         return values[element_index];
     }
 
-    void SetArray(const SFallScriptValue& key, const SFallScriptValue& val, bool allowUnset)
+    void SetArray(const ProgramValue& key, const ProgramValue& val, bool allowUnset)
     {
         if (key.isInt()) {
             auto index = key.asInt();
@@ -116,14 +115,14 @@ public:
         } else if (newLen > 0) {
             if (newLen > ARRAY_MAX_SIZE) newLen = ARRAY_MAX_SIZE; // safety
 
-            std::vector<SFallScriptValue> newValues;
+            std::vector<ProgramValue> newValues;
             newValues.reserve(newLen);
             for (size_t i = 0; i < std::min(newLen, size()); i++) {
                 newValues.push_back(values[i]);
             };
             values = newValues;
         } else if (newLen >= ARRAY_ACTION_SHUFFLE) {
-            ListSort(values, newLen, std::less<SFallScriptValue>());
+            ListSort(values, newLen, std::less<ProgramValue>());
         }
     }
 };
@@ -131,8 +130,8 @@ public:
 class SFallArrayAssoc : public SFallArray {
 private:
     // TODO: SFall copies strings
-    std::vector<SFallScriptValue> keys;
-    std::map<SFallScriptValue, SFallScriptValue> map;
+    std::vector<ProgramValue> keys;
+    std::map<ProgramValue, ProgramValue> map;
 
     void MapSort(int newLen);
 
@@ -152,26 +151,26 @@ public:
     ProgramValue GetArrayKey(int index)
     {
         if (index < -1 || index > size()) {
-            return SFallScriptValue(0);
+            return ProgramValue(0);
         };
         if (index == -1) { // special index to indicate if array is associative
-            return SFallScriptValue(1);
+            return ProgramValue(1);
         };
 
         return keys[index];
     }
 
-    ProgramValue GetArray(const SFallScriptValue& key)
+    ProgramValue GetArray(const ProgramValue& key)
     {
         auto iter = map.find(key);
         if (iter == map.end()) {
-            return SFallScriptValue(0);
+            return ProgramValue(0);
         };
 
         return iter->second;
     }
 
-    void SetArray(const SFallScriptValue& key, const SFallScriptValue& val, bool allowUnset)
+    void SetArray(const ProgramValue& key, const ProgramValue& val, bool allowUnset)
     {
         auto iter = map.find(key);
 
@@ -186,7 +185,7 @@ public:
             // after assigning zero to a key, no need to store it, because "get_array" returns 0 for non-existent keys: try unset
             if (iter != map.end()) {
                 map.erase(iter);
-                std::vector<SFallScriptValue> newKeys;
+                std::vector<ProgramValue> newKeys;
                 newKeys.reserve(keys.size() - 1);
                 for (auto keyCandidate : keys) {
                     if (keyCandidate == key) {
@@ -215,7 +214,7 @@ public:
 
         // only allow to reduce number of elements (adding range of elements is meaningless for maps)
         if (newLen >= 0 && newLen < size()) {
-            std::vector<SFallScriptValue> newKeys;
+            std::vector<ProgramValue> newKeys;
             newKeys.reserve(newLen);
 
             for (size_t i = 0; i < newLen; i++) {
@@ -242,11 +241,11 @@ void SFallArrayAssoc::MapSort(int type)
     }
 
     if (sortByValue) {
-        ListSort(keys, type, [this](const SFallScriptValue& a, const SFallScriptValue& b) -> bool {
+        ListSort(keys, type, [this](const ProgramValue& a, const ProgramValue& b) -> bool {
             return this->map[a] < this->map[b];
         });
     } else {
-        ListSort(keys, type, std::less<SFallScriptValue>());
+        ListSort(keys, type, std::less<ProgramValue>());
     }
 }
 
@@ -290,7 +289,7 @@ ProgramValue GetArrayKey(ArrayId array_id, int index)
 {
     auto& arr = arrays[array_id];
     if (!arr) {
-        return SFallScriptValue(0);
+        return ProgramValue(0);
     };
     return arr->GetArrayKey(index);
 }
@@ -305,18 +304,18 @@ int LenArray(ArrayId array_id)
     return arr->size();
 }
 
-ProgramValue GetArray(ArrayId array_id, const SFallScriptValue& key)
+ProgramValue GetArray(ArrayId array_id, const ProgramValue& key)
 {
     auto& arr = arrays[array_id];
 
     if (!arr) {
-        return SFallScriptValue(0);
+        return ProgramValue(0);
     };
 
     return arr->GetArray(key);
 }
 
-void SetArray(ArrayId array_id, const SFallScriptValue& key, const SFallScriptValue& val, bool allowUnset)
+void SetArray(ArrayId array_id, const ProgramValue& key, const ProgramValue& val, bool allowUnset)
 {
     auto& arr = arrays[array_id];
     if (!arr) {
diff --git a/src/sfall_arrays.h b/src/sfall_arrays.h
index edf5839..3cc59e6 100644
--- a/src/sfall_arrays.h
+++ b/src/sfall_arrays.h
@@ -3,7 +3,6 @@
 
 #include "interpreter.h"
 #include "object.h"
-#include "sfall_script_value.h"
 #include <cstdint>
 
 namespace fallout {
@@ -18,8 +17,8 @@ ArrayId CreateArray(int len, uint32_t flags);
 ArrayId CreateTempArray(int len, uint32_t flags);
 ProgramValue GetArrayKey(ArrayId array_id, int index);
 int LenArray(ArrayId array_id);
-ProgramValue GetArray(ArrayId array_id, const SFallScriptValue& key);
-void SetArray(ArrayId array_id, const SFallScriptValue& key, const SFallScriptValue& val, bool allowUnset);
+ProgramValue GetArray(ArrayId array_id, const ProgramValue& key);
+void SetArray(ArrayId array_id, const ProgramValue& key, const ProgramValue& val, bool allowUnset);
 void FreeArray(ArrayId array_id);
 void FixArray(ArrayId id);
 void ResizeArray(ArrayId array_id, int newLen);
diff --git a/src/sfall_opcodes.cc b/src/sfall_opcodes.cc
index 5e7f77e..5ca218e 100644
--- a/src/sfall_opcodes.cc
+++ b/src/sfall_opcodes.cc
@@ -18,7 +18,6 @@
 #include "sfall_arrays.h"
 #include "sfall_global_vars.h"
 #include "sfall_lists.h"
-#include "sfall_script_value.h"
 #include "stat.h"
 #include "svga.h"
 #include "tile.h"
@@ -530,7 +529,7 @@ static void opSetArray(Program* program)
     auto key = programStackPopValue(program);
     auto arrayId = programStackPopInteger(program);
 
-    SetArray(arrayId, SFallScriptValue { key }, SFallScriptValue { value }, true);
+    SetArray(arrayId, key, value, true);
 }
 
 // get_array
@@ -540,9 +539,9 @@ static void opGetArray(Program* program)
 
     auto key = programStackPopValue(program);
 
-    auto arrayId = SFallScriptValue { programStackPopValue(program) };
+    auto arrayId = programStackPopValue(program);
     if (arrayId.isInt()) {
-        auto value = GetArray(arrayId.integerValue, SFallScriptValue { key });
+        auto value = GetArray(arrayId.integerValue, key);
         programStackPushValue(program, value);
     } else {
     }
@@ -577,7 +576,7 @@ static void opPartyMemberList(Program* program)
     auto objects = get_all_party_members_objects(includeHidden);
     auto array_id = CreateTempArray(objects.size(), SFALL_ARRAYFLAG_RESERVED);
     for (int i = 0; i < LenArray(array_id); i++) {
-        SetArray(array_id, SFallScriptValue { i }, SFallScriptValue { objects[i] }, false);
+        SetArray(array_id, ProgramValue { i }, ProgramValue { objects[i] }, false);
     }
     programStackPushInteger(program, array_id);
 }