1 files changed, 95 insertions, 0 deletions
diff --git a/nihil.config/store.cc b/nihil.config/store.cc
new file mode 100644
index 0000000..0fb8cc0
--- /dev/null
+++ b/nihil.config/store.cc
@@ -0,0 +1,95 @@
+/*
+ * This source code is released into the public domain.
+ */
+
+module;
+
+#include <coroutine>
+#include <expected>
+#include <filesystem>
+#include <format>
+#include <map>
+
+module nihil.config;
+
+import nihil.error;
+import nihil.generator;
+import nihil.monad;
+
+namespace nihil::config {
+
+store::store() = default;
+
+auto store::get() -> store &
+{
+	static auto instance = store();
+	return instance;
+}
+
+
+auto store::register_option(this store &self, option *object)
+	-> std::expected<void, error>
+{
+	auto [it, okay] = self.m_options.insert(
+				std::pair{object->name(), object});
+
+	if (okay)
+		return {};
+
+	return std::unexpected(error(std::format(
+			"attempt to register duplicate "
+			"configuration option '{0}'",
+			object->name())));
+}
+
+auto store::unregister_option(this store &self, option *object)
+	-> std::expected<void, error>
+{
+	auto it = self.m_options.find(object->name());
+	if (it == self.m_options.end())
+		return std::unexpected(error(std::format(
+			"attempt to unregister non-existent "
+			"configuration option '{}'",
+			object->name())));
+
+	self.m_options.erase(it);
+	return {};
+}
+
+auto store::fetch(this store const &self, std::string_view name)
+	-> std::expected<option const *, error>
+{
+	if (auto it = self.m_options.find(name); it != self.m_options.end())
+		return it->second;
+
+	return std::unexpected(error(std::format(
+		"unknown configuration option '{}'",
+		name)));
+}
+
+auto store::fetch(this store &self, std::string_view name)
+	-> std::expected<option *, error>
+{
+	auto opt = co_await static_cast<store const &>(self).fetch(name);
+	co_return const_cast<option *>(opt);
+}
+
+auto store::all(this store const &self) -> nihil::generator<option const *>
+{
+	for (auto &&it : self.m_options)
+		co_yield it.second;
+}
+
+auto store::all(this store &self) -> nihil::generator<option *>
+{
+	for (auto &&it : self.m_options)
+		co_yield it.second;
+}
+
+auto get_option(std::string_view option_name)
+	-> std::expected<option *, error>
+{
+	co_return co_await store::get().fetch(option_name);
+}
+
+} // namespace nihil::config