cli: improve command dispatch a bit

1 files changed, 57 insertions, 0 deletions

diff --git a/nihil.cli/registry.cc b/nihil.cli/registry.cc
new file mode 100644
index 0000000..e35078d
--- /dev/null
+++ b/nihil.cli/registry.cc
@@ -0,0 +1,57 @@
+/*
+ * This source code is released into the public domain.
+ */
+
+module;
+
+#include <cstdio>
+#include <exception>
+#include <memory>
+#include <vector>
+
+module nihil.cli;
+
+namespace nihil {
+
+/*
+ * Get the registry storage.  Because this is called from global ctors,
+ * it handles exceptions itself.
+ */
+auto get_registry() noexcept -> std::vector<std::shared_ptr<command_node>> &
+try {
+	static auto commands = std::vector<std::shared_ptr<command_node>>();
+	return commands;
+} catch (std::exception const &exc) {
+	std::printf("%s\n", exc.what());
+	std::exit(1);
+} catch (...) {
+	std::printf("get_registered_commands(): unknown error\n");
+	std::exit(1);
+}
+
+/*
+ * Register a new command.
+ */
+auto register_command(command *cmd) noexcept -> void
+try {
+	auto null_deleter = [] (command_node const *) -> void {};
+
+	auto &commands = get_registry();
+	commands.emplace_back(cmd, null_deleter);
+} catch (std::exception const &exc) {
+	std::printf("%s\n", exc.what());
+	std::exit(1);
+} catch (...) {
+	std::printf("get_registered_commands(): unknown error\n");
+	std::exit(1);
+}
+
+/*
+ * Get the list of registered commands.
+ */
+auto get_registered_commands() -> std::span<std::shared_ptr<command_node>>
+{
+	return {get_registry()};
+}
+
+} // namespace nihil