diff --git a/.clang-tidy b/.clang-tidy
index 88d2f52..1021a8a 100755
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -28,7 +28,8 @@ Checks: >
   -cppcoreguidelines-macro-usage,
   -cppcoreguidelines-owning-memory,
   -cppcoreguidelines-non-private-member-variables-in-classes,
-  -cppcoreguidelines-pro-bounds-avoid-unchecked-container-access
+  -cppcoreguidelines-pro-bounds-avoid-unchecked-container-access,
+  -cppcoreguidelines-pro-bounds-array-to-pointer-decay
 
 WarningsAsErrors: "*"
 
@@ -95,4 +96,4 @@ CheckOptions:
   - key: readability-identifier-naming.EnumConstantCase
     value: CamelCase
   - key: readability-identifier-naming.ScopedEnumConstantCase
-    value: CamelCase
\ No newline at end of file
+    value: CamelCase
diff --git a/furvm/include/furvm/context.hpp b/furvm/include/furvm/context.hpp
index ba0f6b8..436ff35 100644
--- a/furvm/include/furvm/context.hpp
+++ b/furvm/include/furvm/context.hpp
@@ -2,6 +2,7 @@
 #define FURVM_CONTEXT_HPP
 
 #include "furlang/arena.hpp"
+#include "furvm/executor.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/module.hpp"
 
@@ -40,12 +41,13 @@ public:
      * @brief Emplaces a new module in this context.
      *
      * @param args Arguments to forward to module's constructor.
-     * @return An index to the emplaced module.
+     * @return A handle to the module.
      */
     template <typename... Args, typename = std::enable_if_t<std::is_constructible_v<mod, Args...>>>
-    auto& emplace_module(Args&&... args) {
-        mod_p mod = std::make_shared<class mod>(std::forward<Args>(args)...);
-        return m_modules.emplace(mod->name(), std::move(mod)).first->second;
+    mod_h emplace_module(Args&&... args) {
+        mod_p       mod  = std::make_shared<class mod>(std::forward<Args>(args)...);
+        std::string name = mod->name();
+        return { name, m_modules[name] = std::move(mod) };
     }
 
     /**
@@ -89,9 +91,11 @@ public:
     constexpr size_t module_count() const { return m_modules.size(); }
 public:
     template <typename... Args, typename = std::enable_if_t<std::is_constructible_v<executor, Args...>>>
-    auto& emplace_executor(Args&&... args) {
-        executor_p executor = std::make_shared<class executor>(std::forward<Args>(args)...);
-        return m_executors.emplace_back(std::move(executor));
+    executor_h emplace_executor(Args&&... args) {
+        executor    executor(std::forward<Args>(args)...);
+        executor_id id = m_executors.size();
+        m_executors.emplace_back(std::move(executor));
+        return { id, m_executors[id] };
     }
 public:
     /**
@@ -101,8 +105,8 @@ public:
 private:
     std::unordered_map<std::string, mod_p> m_modules;
 
-    std::vector<thing_p>    m_things;
-    std::vector<executor_p> m_executors;
+    std::vector<thing_p>  m_things;
+    std::vector<executor> m_executors;
 
     std::queue<thing_id> m_deadThings;
     std::vector<void*>   m_deadThingData;
diff --git a/furvm/include/furvm/executor.hpp b/furvm/include/furvm/executor.hpp
index 88f69be..24436fe 100644
--- a/furvm/include/furvm/executor.hpp
+++ b/furvm/include/furvm/executor.hpp
@@ -33,7 +33,7 @@ public:
      * Call frame.
      */
     struct frame {
-        mod_p       mod;       /**< Shared pointer to a module with the bytecode. */
+        mod_h       mod;       /**< Shared pointer to a module with the bytecode. */
         std::size_t position;  /**< Cursor to a current instruction in the bytecode. */
         std::size_t stackBase; /**< Snapshot of the stack size before this frame. */
 
@@ -60,8 +60,15 @@ public:
      */
     executor& operator=(executor&&) noexcept = default;
 
-    executor(const executor&)            = delete;
-    executor& operator=(const executor&) = delete;
+    /**
+     * @brief Copy constructor.
+     */
+    executor(const executor&) = default;
+
+    /**
+     * @brief Copy constructor.
+     */
+    executor& operator=(const executor&) = default;
 public:
     /**
      * @brief Returns flags of this executor.
@@ -76,7 +83,7 @@ public:
      * @param mod Module.
      * @param function Function handle.
      */
-    void push_frame(const mod_p& mod, function_id function);
+    void push_frame(const mod_h& mod, const function_h& function);
 
     /**
      * @brief Pops the top frame.
diff --git a/furvm/include/furvm/function.hpp b/furvm/include/furvm/function.hpp
index ca19c01..e09bacb 100644
--- a/furvm/include/furvm/function.hpp
+++ b/furvm/include/furvm/function.hpp
@@ -56,8 +56,15 @@ public:
      */
     function& operator=(function&&) noexcept;
 
-    function(const function&)            = delete;
-    function& operator=(const function&) = delete;
+    /**
+     * @brief Copy constructor.
+     */
+    function(const function&);
+
+    /**
+     * @brief Copy constructor.
+     */
+    function& operator=(const function&);
 public:
     /**
      * @brief Returns a name of this function.
diff --git a/furvm/include/furvm/module.hpp b/furvm/include/furvm/module.hpp
index bfa167d..c0d8e9b 100644
--- a/furvm/include/furvm/module.hpp
+++ b/furvm/include/furvm/module.hpp
@@ -4,7 +4,7 @@
 #include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
 
-#include <memory>
+#include <stdexcept>
 #include <string>
 #include <unordered_map>
 #include <utility>
@@ -91,8 +91,9 @@ public:
      * @return The function.
      */
     template <typename Name>
-    constexpr const function_p& function_at(Name&& name) const {
-        return m_functions.at(std::forward<Name>(name));
+    function_h function_at(Name&& name) const {
+        if (auto it = m_functionMap.find(std::forward<Name>(name)); it != m_functionMap.end()) return it->second;
+        throw std::runtime_error("invalid function");
     }
 
     /**
@@ -101,22 +102,23 @@ public:
      * @param id Id of the function.
      * @return The function.
      */
-    constexpr const function_p& function_at(function_id id) const { return m_functions.at(id); }
+    function_h function_at(function_id id) const { return { id, m_functions.at(id) }; }
 
     template <typename... Args>
-    function_id emplace_function(Args&&... args) {
-        function_p function = std::make_shared<class function>(std::forward<Args>(args)...);
-        m_functionMap.emplace(function->name(), function);
-        function_id id = m_functions.size();
-        m_functions.emplace_back(std::move(function));
-        return id;
+    function_h emplace_function(Args&&... args) {
+        function    function(std::forward<Args>(args)...);
+        std::string name   = function.name();
+        function_id id     = m_functions.size();
+        function_h  handle = { id, m_functions.emplace_back(std::move(function)) };
+        m_functionMap.emplace(std::move(name), handle);
+        return handle;
     }
 private:
     std::string m_name;
     bytecode_t  m_bytecode;
 
-    std::unordered_map<std::string, function_p> m_functionMap;
-    std::vector<function_p>                     m_functions;
+    std::unordered_map<std::string, function_h> m_functionMap;
+    std::vector<function>                       m_functions;
 };
 
 } // namespace furvm
diff --git a/furvm/src/context.cpp b/furvm/src/context.cpp
index 6dcb1c4..9cb27e7 100644
--- a/furvm/src/context.cpp
+++ b/furvm/src/context.cpp
@@ -13,4 +13,4 @@ void context::collect() {
     }
 }
 
-} // namespace furvm
\ No newline at end of file
+} // namespace furvm
diff --git a/furvm/src/executor.cpp b/furvm/src/executor.cpp
index 3514bcd..4feb333 100644
--- a/furvm/src/executor.cpp
+++ b/furvm/src/executor.cpp
@@ -13,10 +13,9 @@
 
 namespace furvm {
 
-void executor::push_frame(const mod_p& mod, function_id function) {
-    const auto& func = mod->function_at(function);
-    if (func->type() != function_t::Normal) throw std::runtime_error("unexpected function type");
-    m_frames.emplace((struct executor::frame){ mod, func->position(), m_stack.size() });
+void executor::push_frame(const mod_h& mod, const function_h& function) {
+    if (function->type() != function_t::Normal) throw std::runtime_error("unexpected function type");
+    m_frames.emplace((struct executor::frame){ mod, function->position(), m_stack.size() });
 }
 
 struct executor::frame executor::pop_frame() {
@@ -83,12 +82,12 @@ void executor::step() {
 
     struct frame& frame = m_frames.top();
 
-    instruction_t instr = static_cast<instruction_t>(frame.mod->byte(frame.position++));
+    instruction_t instr = static_cast<instruction_t>((*frame.mod)->byte(frame.position++));
     switch (instr) {
     case instruction_t::NoOperation: break;
     case instruction_t::PushB2I: {
         auto thing     = std::make_shared<class thing>(m_context, thing_t::Int32);
-        thing->int32() = frame.mod->byte(frame.position++);
+        thing->int32() = (*frame.mod)->byte(frame.position++);
         push_thing(std::move(thing));
     } break;
     case instruction_t::Drop: {
@@ -156,37 +155,38 @@ void executor::step() {
         push_thing(lhs >= rhs);
     } break;
     case instruction_t::Load: {
-        variable_t variable = static_cast<std::uint16_t>(frame.mod->byte(frame.position)) |
-                              (static_cast<std::uint16_t>(frame.mod->byte(frame.position + 1)) << 8);
+        variable_t variable = static_cast<std::uint16_t>((*frame.mod)->byte(frame.position)) |
+                              (static_cast<std::uint16_t>((*frame.mod)->byte(frame.position + 1)) << 8);
         frame.position     += 2;
         push_thing(load_thing(variable));
     } break;
     case instruction_t::Store: {
-        variable_t variable = static_cast<std::uint16_t>(frame.mod->byte(frame.position)) |
-                              (static_cast<std::uint16_t>(frame.mod->byte(frame.position + 1)) << 8);
+        variable_t variable = static_cast<std::uint16_t>((*frame.mod)->byte(frame.position)) |
+                              (static_cast<std::uint16_t>((*frame.mod)->byte(frame.position + 1)) << 8);
         frame.position     += 2;
         store_thing(variable, std::move(pop_thing()));
     } break;
     case instruction_t::Call: {
-        function_id funcId = static_cast<std::uint16_t>(frame.mod->byte(frame.position)) |
-                             (static_cast<std::uint16_t>(frame.mod->byte(frame.position + 1)) << 8);
+        function_id funcId = static_cast<std::uint16_t>((*frame.mod)->byte(frame.position)) |
+                             (static_cast<std::uint16_t>((*frame.mod)->byte(frame.position + 1)) << 8);
         frame.position    += 2;
 
-        const function_p& function = frame.mod->function_at(funcId);
+        const function_h& function = (*frame.mod)->function_at(funcId);
         switch (function->type()) {
-        case function_t::Normal: push_frame(frame.mod, funcId); break;
+        case function_t::Normal: push_frame(frame.mod, function); break;
         case function_t::Native: function->native()(*this); break;
         case function_t::Import: {
-            const mod_p& impMod = m_context->m_modules.at(function->imported_module());
-            push_frame(frame.mod, function->imported_function());
+            // const mod_p& impMod = m_context->m_modules.at(function->imported_module());
+            // push_frame(frame.mod, function->imported_function());
+            throw std::runtime_error("unimplemented");
         } break;
         }
     } break;
     case instruction_t::Jump: {
-        frame.position += frame.mod->byte(frame.position++);
+        frame.position += (*frame.mod)->byte(frame.position++);
     } break;
     case instruction_t::JumpNotZero: {
-        byte offset = frame.mod->byte(frame.position++);
+        byte offset = (*frame.mod)->byte(frame.position++);
         auto cond   = pop_thing();
         if (cond->int32() != 0) frame.position += offset;
     } break;
diff --git a/furvm/src/function.cpp b/furvm/src/function.cpp
index baf34c8..82df446 100644
--- a/furvm/src/function.cpp
+++ b/furvm/src/function.cpp
@@ -54,4 +54,41 @@ function& function::operator=(function&& other) noexcept {
     return *this;
 }
 
+function::function(const function& other)
+  : m_name(other.m_name), m_type(other.m_type) {
+    switch (m_type) {
+    case function_t::Normal: {
+        m_value.position = other.m_value.position;
+    } break;
+    case function_t::Native: {
+        new (&m_value.native) native_function(other.m_value.native);
+    } break;
+    case function_t::Import: {
+        m_value.imp.moduleName = other.m_value.imp.moduleName;
+        m_value.imp.function   = other.m_value.imp.function;
+    } break;
+    }
+}
+
+function& function::operator=(const function& other) {
+    if (this == &other) return *this;
+
+    m_name = other.m_name;
+    m_type = other.m_type;
+    switch (m_type) {
+    case function_t::Normal: {
+        m_value.position = other.m_value.position;
+    } break;
+    case function_t::Native: {
+        new (&m_value.native) native_function(other.m_value.native);
+    } break;
+    case function_t::Import: {
+        m_value.imp.moduleName = other.m_value.imp.moduleName;
+        m_value.imp.function   = other.m_value.imp.function;
+    } break;
+    }
+
+    return *this;
+}
+
 } // namespace furvm
diff --git a/furvm/src/main.cpp b/furvm/src/main.cpp
index 806fa6d..ebf38e8 100644
--- a/furvm/src/main.cpp
+++ b/furvm/src/main.cpp
@@ -3,6 +3,7 @@
 #include "furvm/context.hpp"
 #include "furvm/executor.hpp"
 #include "furvm/function.hpp"
+#include "furvm/fwd.hpp"
 #include "furvm/instruction.hpp"
 #include "furvm/serializer.hpp"
 #include "furvm/thing.hpp"
@@ -24,11 +25,11 @@ static constexpr std::array<furvm::byte, 8> s_bytecode = {
 int main(void) {
     auto context = std::make_shared<furvm::context>();
 
-    auto mainModule = context->emplace_module("main", s_bytecode.begin(), s_bytecode.end());
-    mainModule->emplace_function("main", 0);
+    furvm::mod_h      mainModule = context->emplace_module("main", s_bytecode.begin(), s_bytecode.end());
+    furvm::function_h mainFunc   = (*mainModule)->emplace_function("main", 0);
 
-    auto executor = context->emplace_executor(context);
-    executor->push_frame(mainModule, 0);
+    furvm::executor_h executor = context->emplace_executor(context);
+    executor->push_frame(mainModule, mainFunc);
 
     static constexpr std::size_t FPC = 3; // Frames per collection
 
diff --git a/furvm/src/serializer.cpp b/furvm/src/serializer.cpp
index 58ce2d4..9825766 100644
--- a/furvm/src/serializer.cpp
+++ b/furvm/src/serializer.cpp
@@ -73,7 +73,7 @@ bool serializer::serialize_module(std::ostream& os, const mod_p& mod) {
 
     write_u32(os, mod->m_functions.size());
     for (function_id id = 0; id < static_cast<function_id>(mod->m_functions.size()); ++id) {
-        const auto& func = mod->m_functions[id];
+        const auto& func = mod->function_at(id);
         write_u16(os, id);
         write_u8(os, static_cast<std::uint8_t>(func->type()));
         switch (func->type()) {