Support complex syntax for command line arguments

Support parameters prefixed by '-' or '--'.
Support parameters in form 'key=value'

config.mk

@@ -13,7 +13,7 @@ VERSION := $(MAJOR).$(MINOR).$(PATCH)-dev+$(COMMIT)
 
 CXXFLAGS:=$(CXXFLAGS) -std=c++20 -Wall -Wextra -Werror=switch -Werror=return-type -Werror=unused-result
 CPPFLAGS:=$(CPPFLAGS) -DMusique_Version='"$(VERSION)"' \
-	-Ilib/expected/ -I. -Ilib/bestline/ -Ilib/rtmidi/ -Ilib/link/include -Ilib/asio/include/
+	-Ilib/expected/ -I. -Ilib/bestline/ -Ilib/rtmidi/ -Ilib/link/include -Ilib/asio/include/ -Ilib/edit_distance.cc/
 LDFLAGS=-flto
 LDLIBS= -lpthread
 

musique/cmd.cc

@@ -50,7 +50,6 @@ static constexpr std::array all_parameters = [] {
 			std::cout << *maybe_docs << std::endl;
 			return;
 		}
-
 		std::cerr << "musique: error: cannot find documentation for given builtin" << std::endl;
 		std::exit(1);
 	};
@@ -99,42 +98,89 @@ static constexpr std::array all_parameters = [] {
 	};
 }();
 
-bool cmd::accept_commandline_argument(std::vector<cmd::Run> &runnables, std::span<char const*> &args)
-{
-	if (args.empty())
-		return false;
 
-	for (auto const& [name, handler] : all_parameters) {
-		// TODO Parameters starting with - or -- should be considered equal
-		if (name != args.front()) {
-			continue;
-		}
-		args = args.subspan(1);
-		std::visit(Overloaded {
-			[](Empty_Argument const& h) {
-				h();
-			},
-			[&args, name=name](Requires_Argument const& h) {
-				if (args.empty()) {
-					std::cerr << "musique: error: option " << std::quoted(name) << " requires an argument" << std::endl;
-					std::exit(1);
-				}
-				h(args.front());
-				args = args.subspan(1);
-			},
-			[&, name=name](Defines_Code const& h) {
-				if (args.empty()) {
-					std::cerr << "musique: error: option " << std::quoted(name) << " requires an argument" << std::endl;
-					std::exit(1);
-				}
-				runnables.push_back(h(args.front()));
-				args = args.subspan(1);
-			}
-		}, handler);
-		return true;
+// Supported types of argument input:
+// With arity = 0
+//   -i -j -k ≡ --i --j --k ≡ i j k
+// With arity = 1
+//   -i 1 -j 2 ≡ --i 1 --j 2 ≡ i 1 j 2 ≡ --i=1 --j=2
+// Arity ≥ 2 is not supported
+std::optional<std::string_view> cmd::accept_commandline_argument(std::vector<cmd::Run> &runnables, std::span<char const*> &args)
+{
+	if (args.empty()) {
+		return std::nullopt;
 	}
 
-	return false;
+	// This struct when function returns automatically ajust number of arguments used
+	struct Fix_Args_Array
+	{
+		std::string_view name() const { return m_name; }
+
+		std::optional<std::string_view> value() const
+		{
+			if (m_has_value) { m_success = m_value_consumed = true; return m_value; }
+			return std::nullopt;
+		}
+
+		void mark_success() { m_success = true; }
+
+		~Fix_Args_Array() { args = args.subspan(int(m_success) + (!m_packed * int(m_value_consumed))); }
+
+		std::span<char const*> &args;
+		std::string_view m_name = {};
+		std::string_view m_value = {};
+		bool m_has_value = false;
+		bool m_packed = false;
+		mutable bool m_success = false;
+		mutable bool m_value_consumed = false;
+	} state { .args = args };
+
+	std::string_view s = args.front();
+	if (s.starts_with("--")) s.remove_prefix(2);
+	if (s.starts_with('-'))  s.remove_prefix(1);
+
+	state.m_name = s;
+
+	if (auto p = s.find('='); p != std::string_view::npos) {
+		state.m_name = s.substr(0, p);
+		state.m_value = s.substr(p+1);
+		state.m_has_value = true;
+		state.m_packed = true;
+	} else if (args.size() >= 2) {
+		state.m_has_value = true;
+		state.m_value = args[1];
+	}
+
+	for (auto const& [name, handler] : all_parameters) {
+		if (name != state.name()) {
+			continue;
+		}
+		std::visit(Overloaded {
+			[&state](Empty_Argument const& h) {
+				state.mark_success();
+				h();
+			},
+			[&state, name=name](Requires_Argument const& h) {
+				auto arg = state.value();
+				if (!arg) {
+					std::cerr << "musique: error: option " << std::quoted(name) << " requires an argument" << std::endl;
+					std::exit(1);
+				}
+				h(*arg);
+			},
+			[&state, &runnables, name=name](Defines_Code const& h) {
+				auto arg = state.value();
+				if (!arg) {
+					std::cerr << "musique: error: option " << std::quoted(name) << " requires an argument" << std::endl;
+					std::exit(1);
+				}
+				runnables.push_back(h(*arg));
+			}
+		}, handler);
+		return std::nullopt;
+	}
+
+	return state.name();
 }
 
 

musique/cmd.hh

@@ -1,6 +1,7 @@
 #ifndef MUSIQUE_CMD_HH
 #define MUSIQUE_CMD_HH
 
+#include <optional>
 #include <span>
 #include <string_view>
 #include <variant>
@@ -22,7 +23,7 @@ namespace cmd
 	};
 
 	/// Accept and execute next command line argument with its parameters if it has any
-	bool accept_commandline_argument(std::vector<cmd::Run> &runnables, std::span<char const*> &args);
+	std::optional<std::string_view> accept_commandline_argument(std::vector<cmd::Run> &runnables, std::span<char const*> &args);
 
 	/// Print all arguments that are similar to one provided
 	void print_close_matches(std::string_view arg);

musique/main.cc

@@ -321,35 +321,21 @@ static Result<bool> handle_repl_session_commands(std::string_view input, Runner
 /// Fancy main that supports Result forwarding on error (Try macro)
 static std::optional<Error> Main(std::span<char const*> args)
 {
+	enable_repl = args.empty();
+
 	if (cmd::is_tty() && getenv("NO_COLOR") == nullptr) {
 		pretty::terminal_mode();
 	}
 
-
 	std::vector<cmd::Run> runnables;
 
 
-	for (;;) if (!cmd::accept_commandline_argument(runnables, args)) {
-		if (args.size()) {
-			std::cerr << "musique: error: Failed to recognize parameter " << std::quoted(args.front()) << std::endl;
-			cmd::print_close_matches(args.front());
-			std::exit(1);
-		}
-		break;
+	while (args.size()) if (auto failed = cmd::accept_commandline_argument(runnables, args)) {
+		std::cerr << "musique: error: Failed to recognize parameter " << std::quoted(*failed) << std::endl;
+		cmd::print_close_matches(args.front());
+		std::exit(1);
 	}
 
-		/*
-		if (arg == "--ast") {
-			ast_only_mode = true;
-			continue;
-		}
-
-		if (arg == "--version" || arg == "-v") {
-			std::cout << Musique_Version << std::endl;
-			return {};
-		}
-		*/
-
 	Runner runner;
 
 	for (auto const& [type, argument] : runnables) {