From a749f5aabd08c7e21bb3b6b5a6caece144105dc1 Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Tue, 15 Apr 2025 08:40:10 +0200
Subject: [PATCH] Designed read as a functor

---
 include/sqlgen/read.hpp                      | 22 ++++++++--
 tests/sqlite/test_write_and_read_to_file.cpp | 44 ++++++++++++++++++++
 2 files changed, 62 insertions(+), 4 deletions(-)
 create mode 100644 tests/sqlite/test_write_and_read_to_file.cpp

diff --git a/include/sqlgen/read.hpp b/include/sqlgen/read.hpp
index aa3380a..5ab068b 100644
--- a/include/sqlgen/read.hpp
+++ b/include/sqlgen/read.hpp
@@ -11,7 +11,7 @@
 namespace sqlgen {
 
 template <class ContainerType>
-Result<ContainerType> read(const Ref<Connection>& _conn) noexcept {
+Result<ContainerType> read_impl(const Ref<Connection>& _conn) {
   if constexpr (internal::is_range_v<ContainerType>) {
     using ValueType = typename ContainerType::value_type::value_type;
     const auto query = transpilation::to_select_from<ValueType>();
@@ -32,16 +32,30 @@ Result<ContainerType> read(const Ref<Connection>& _conn) noexcept {
     };
 
     using ValueType = typename ContainerType::value_type;
-    return read<Range<ValueType>>(_conn).and_then(to_container);
+    return read_impl<Range<ValueType>>(_conn).and_then(to_container);
   }
 }
 
 template <class ContainerType>
-Result<ContainerType> read(const Result<Ref<Connection>>& _res) noexcept {
+Result<ContainerType> read_impl(const Result<Ref<Connection>>& _res) {
   return _res.and_then(
-      [](const auto& _conn) { return read<ContainerType>(_conn); });
+      [](const auto& _conn) { return read_impl<ContainerType>(_conn); });
 }
 
+template <class ContainerType>
+struct Read {
+  Result<ContainerType> operator()(const auto& _conn) const noexcept {
+    try {
+      return read_impl<ContainerType>(_conn);
+    } catch (std::exception& e) {
+      return error(e.what());
+    }
+  }
+};
+
+template <class ContainerType>
+const auto read = Read<ContainerType>();
+
 }  // namespace sqlgen
 
 #endif
diff --git a/tests/sqlite/test_write_and_read_to_file.cpp b/tests/sqlite/test_write_and_read_to_file.cpp
new file mode 100644
index 0000000..4633617
--- /dev/null
+++ b/tests/sqlite/test_write_and_read_to_file.cpp
@@ -0,0 +1,44 @@
+#include <gtest/gtest.h>
+
+#include <cstdio>
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/sqlite.hpp>
+#include <vector>
+
+namespace test_write_and_read_to_file {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  int age;
+};
+
+TEST(sqlite, test_write_and_read_to_file) {
+  const auto people1 = std::vector<Person>(
+      {Person{
+           .id = 0, .first_name = "Homer", .last_name = "Simpson", .age = 45},
+       Person{.id = 1, .first_name = "Bart", .last_name = "Simpson", .age = 10},
+       Person{.id = 2, .first_name = "Lisa", .last_name = "Simpson", .age = 8},
+       Person{
+           .id = 3, .first_name = "Maggie", .last_name = "Simpson", .age = 0}});
+
+  sqlgen::sqlite::connect("test.db")
+      .and_then([&](auto&& _conn) { return sqlgen::write(_conn, people1); })
+      .value();
+
+  const auto people2 = sqlgen::sqlite::connect("test.db")
+                           .and_then(sqlgen::read<std::vector<Person>>)
+                           .value();
+
+  std::remove("test.db");
+
+  const auto json1 = rfl::json::write(people1);
+  const auto json2 = rfl::json::write(people2);
+
+  EXPECT_EQ(json1, json2);
+}
+
+}  // namespace test_write_and_read_to_file