Started writing from_str and from_str_vec

include/sqlgen/internal/from_str.hpp

@@ -0,0 +1,65 @@
+#ifndef SQLGEN_INTERNAL_FROM_STR_HPP_
+#define SQLGEN_INTERNAL_FROM_STR_HPP_
+
+#include <optional>
+#include <string>
+#include <type_traits>
+
+#include "../Result.hpp"
+#include "../parsing/has_reflection_method.hpp"
+#include "../parsing/is_nullable.hpp"
+
+namespace sqlgen::internal {
+
+template <class T>
+Result<T> from_str(const std::optional<std::string>& _str) {
+  using Type = std::remove_cvref_t<T>;
+
+  if constexpr (parsing::has_reflection_method<Type>) {
+    return from_str<typename Type::ReflectionType>(_str).transform(
+        [](auto&& _v) { return Type(std::move(_v)); });
+
+  } else if constexpr (parsing::is_nullable_v<Type>) {
+    if (!_str) {
+      return Type();
+    }
+
+    if constexpr (parsing::is_ptr<Type>::value) {
+      return from_str<typename Type::element_type>(_str).transform(
+          [](auto&& _v) { return Type(std::move(_v)); });
+
+    } else {
+      return from_str<typename Type::value_type>(_str).transform(
+          [](auto&& _v) { return Type(std::move(_v)); });
+    }
+
+  } else {
+    if (!_str) {
+      return error("Encountered NULL value.");
+    }
+
+    if constexpr (std::is_same_v<Type, std::string>) {
+      return *_str;
+
+    } else {
+      try {
+        if constexpr (std::is_floating_point_v<Type>) {
+          return static_cast<Type>(std::stod(*_str));
+        } else if constexpr (std::is_integral_v<Type>) {
+          return static_cast<type>(std::stoll(*_str));
+        } else if (std::is_same_v<Type, bool>) {
+          return std::stoi(*_str) != 0;
+        } else {
+          static_assert(rfl::always_false<Type>, "Unsupported type");
+        }
+
+      } catch (std::exception& e) {
+        return error(e.what());
+      }
+    }
+  }
+}
+
+}  // namespace sqlgen::internal
+
+#endif

include/sqlgen/internal/from_str_vec.hpp

@@ -0,0 +1,25 @@
+#ifndef SQLGEN_INTERNAL_FROM_STR_VEC_HPP_
+#define SQLGEN_INTERNAL_FROM_STR_VEC_HPP_
+
+#include <optional>
+#include <rfl.hpp>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+#include "../Result.hpp"
+
+namespace sqlgen::internal {
+
+template <class T>
+Result<T> from_str_vec(
+    const std::vector<std::optional<std::string>>& _str_vec) {
+  T t;
+  const auto view = rfl::to_view(t);
+
+  return t;
+}
+
+}  // namespace sqlgen::internal
+
+#endif