feat(furvm): add basic function

furvm/src/function.cpp

@@ -0,0 +1,43 @@
+#include "furvm/function.hpp"
+
+namespace furvm {
+
+function::function(funkcja, function_handle id, std::size_t position, const mod_p& mod)
+  : m_id(id), m_type(function_t::Normal), m_module(mod), m_value(position) {}
+
+function::function(funkcja, function_handle id, const native_function& native, const mod_p& mod)
+  : m_id(id), m_type(function_t::Native), m_module(mod), m_value(native) {}
+
+function::function(function&& other) noexcept
+  : m_id(other.m_id), m_type(other.m_type), m_module(std::move(other.m_module)) {
+    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(std::move(other.m_value.native));
+    } break;
+    }
+    other.m_value.position = 0;
+}
+
+function& function::operator=(function&& other) noexcept {
+    if (this == &other) return *this;
+
+    m_id     = other.m_id;
+    m_type   = other.m_type;
+    m_module = std::move(other.m_module);
+    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(std::move(other.m_value.native));
+    } break;
+    }
+    other.m_value.position = 0;
+
+    return *this;
+}
+
+} // namespace furvm