Removed cppast dependency

src/common/types.h

@@ -17,6 +17,7 @@
  */
 #pragma once
 
+#include <cassert>
 #include <cstdint>
 #include <optional>
 #include <unordered_set>
@@ -26,8 +27,89 @@ namespace clanguml::common {
 
 using id_t = int64_t;
 
-template <typename T>
-using optional_ref = std::optional<std::reference_wrapper<T>>;
+template <typename T> class optional_ref {
+public:
+    using optional_type = T;
+
+    optional_ref()
+        : value_{nullptr}
+    {
+    }
+
+    optional_ref(T &value) { value_ = &value; }
+
+    optional_ref(const T &value) { value_ = &value; }
+
+    optional_ref(optional_ref &right) { value_ = right.get(); }
+
+    template <typename V,
+        typename = std::enable_if<
+            std::is_base_of_v<optional_type, typename V::optional_type> ||
+            std::is_same_v<optional_type, typename V::optional_type>>>
+    optional_ref(const V &t)
+    {
+        value_ = t.get();
+    }
+
+    template <typename V,
+        typename = std::enable_if<
+            std::is_base_of_v<optional_type, typename V::optional_type> ||
+            std::is_same_v<optional_type, typename V::optional_type>>>
+    optional_ref(V &&t)
+    {
+        value_ = t.get();
+        t.reset();
+    }
+
+    template <typename V,
+        typename = std::enable_if<std::is_base_of_v<optional_type, V>>>
+    optional_ref(const std::reference_wrapper<V> &t)
+    {
+        value_ = &t.get();
+    }
+
+    optional_ref &operator=(const optional_ref &right)
+    {
+        if (this == &right)
+            return *this;
+
+        value_ = right.value_;
+        return *this;
+    }
+
+    optional_ref &operator=(optional_ref &&right) noexcept
+    {
+        if (this == &right)
+            return *this;
+
+        value_ = right.value_;
+        right.reset();
+        return *this;
+    }
+
+    bool has_value() const noexcept { return value_ != nullptr; }
+
+    operator bool() const noexcept { return has_value(); }
+
+    const T &value() const
+    {
+        assert(value_ != nullptr);
+        return *value_;
+    }
+
+    T &value()
+    {
+        assert(value_ != nullptr);
+        return *value_;
+    }
+
+    void reset() { value_ = nullptr; }
+
+    T *get() const { return value_; }
+
+private:
+    T *value_;
+};
 
 template <typename T>
 using reference_vector = std::vector<std::reference_wrapper<T>>;