cli: clean up

2 files changed, 48 insertions, 47 deletions

diff --git a/nihil.cli/command_tree.ccm b/nihil.cli/command_tree.ccm
index 6eae9e6..6cfabe9 100644
--- a/nihil.cli/command_tree.ccm
+++ b/nihil.cli/command_tree.ccm
@@ -30,6 +30,16 @@ struct command_tree_node final
 	{
 	}
 
+	// Not copyable.
+	command_tree_node(command_tree_node const &) = delete;
+	auto operator=(command_tree_node const &) -> command_tree_node & = delete;
+
+	// Movable.
+	command_tree_node(command_tree_node &&) = default;
+	auto operator=(command_tree_node &&) -> command_tree_node & = default;
+
+	~command_tree_node() = default;
+
 	// Return a child node, or NULL if the child doesn't exist.
 	[[nodiscard]] auto get_child(this command_tree_node const &self,
 	                             std::string_view const child) -> command_tree_node const *
@@ -63,7 +73,7 @@ struct command_tree_node final
 		                  : std::string(child);
 		auto node = command_tree_node(&self, child, std::make_shared<nihil::command>(path));
 
-		auto [it, ok] = self.m_children.emplace(child, node);
+		auto [it, ok] = self.m_children.emplace(child, std::move(node));
 		if (!ok)
 			throw std::logic_error("failed to insert command tree node");
 		return &it->second;
@@ -113,41 +123,41 @@ private:
 struct command_tree
 {
 	// Add a node to the tree.  Returns false if the node already exists.
-	auto insert(this command_tree &self, std::vector<std::string_view> const &path,
+	auto insert(this command_tree &self, std::ranges::range auto &&path,
 	            std::shared_ptr<command> command) -> void
+	requires(std::constructible_from<std::string_view,
+	                                 std::ranges::range_value_t<decltype(path)>>)
 	{
 		auto *this_node = &self.m_root_node;
 
 		// Find the node for this key.
 		for (auto &&this_word : path)
-			this_node = this_node->get_or_create_child(this_word);
+			this_node = this_node->get_or_create_child(std::string_view(this_word));
 
 		// Set the new value.
 		this_node->command(std::move(command));
 	}
 
-	// Find a node in the tree.
-	[[nodiscard]] auto
-	find(this command_tree const &self, int &argc, char **&argv) -> command_tree_node const *
+	// Find a node in the tree.  Returns the node and the remaining unprocessed arguments.
+	[[nodiscard]] auto find(this command_tree const &self, std::ranges::range auto &&args)
+	requires(std::constructible_from<std::string_view,
+					 std::ranges::range_value_t<decltype(args)>>)
 	{
 		auto const *this_node = &self.m_root_node;
 
-		// Iterate until we don't find a child command, then return that node.
-		while (argv[0] != nullptr) {
-			auto const *next_node = this_node->get_child(argv[0]);
-
-			if (next_node == nullptr)
-				return this_node;
-
-			this_node = next_node;
-
-			--argc;
-			++argv;
-		}
-
-		// We ran out of path without finding a valid command.  Return this
-		// node; the caller will notice the missing command.
-		return this_node;
+		auto rest =
+			args | std::views::take_while([&](auto &&str) {
+				auto const *child = this_node->get_child(std::string_view(str));
+				if (child == nullptr)
+					return false;
+				this_node = child;
+				return true;
+			});
+
+		// Force evaluation of the view, otherwise the reference to this_node
+		// would be dangling.
+		auto taken = std::ranges::distance(args) - std::ranges::distance(rest);
+		return std::make_pair(this_node, args | std::views::drop(taken));
 	}
 
 private:
@@ -159,15 +169,9 @@ private:
 {
 	auto tree = command_tree();
 
-	for (auto &&command : get_registered_commands()) {
-		auto split_path = command->path()                                    //
-		                | std::views::split(' ')                             //
-		                | std::views::transform(construct<std::string_view>) //
-		                | std::ranges::to<std::vector>();
-
+	for (auto &&command : get_registered_commands())
 		// Throws std::logic_error on duplicates.
-		tree.insert(split_path, command);
-	}
+		tree.insert(command->path() | std::views::split(' '), command);
 
 	return tree;
 }
diff --git a/nihil.cli/dispatch_command.cc b/nihil.cli/dispatch_command.cc
index 6cf7f05..6e3a757 100644
--- a/nihil.cli/dispatch_command.cc
+++ b/nihil.cli/dispatch_command.cc
@@ -1,9 +1,9 @@
 // This source code is released into the public domain.
 module;
 
-#include <stdlib.h> // getprogname, NOLINT
+#include <stdlib.h>   // getprogname, NOLINT
 #include <sysexits.h> // EX_USAGE
-#include <unistd.h> // getopt
+#include <unistd.h>   // getopt
 
 module nihil.cli;
 
@@ -19,39 +19,36 @@ auto print_commands(command_tree_node const &node) -> void
 	for (auto &&child : node.children())
 		std::print(std::cerr, "  {}\n", child.command().path());
 }
-}
+} // namespace
 
 auto dispatch_command(int argc, char **argv) -> int
 {
-	auto tree = build_command_tree();
-
-	// The caller should have stripped argv[0] already.  find() will
-	// strip all the remaining elements except the last, which means
-	// argv[0] will be set to something reasonable for the next call
-	// to getopt().
-
-	// find() never returns nullptr; at worst it will return the root node.
-	auto const *node = tree.find(argc, argv);
-	auto const &command = node->command();
-
 	// Reset getopt(3) for the command, in case main() used it already.
 	optreset = 1;
 	optind = 1;
 
+	// Node that tree.find() never fails, at worst it will return the root node.
+	auto tree = build_command_tree();
+	auto [node, rest] = tree.find(std::span(argv, argc));
+	auto const &command = node->command();
+
 	// Set the program name to the existing progname plus the full path to the command being
 	// invoked; this makes error messages nicer. Save the old progname so we can restore it
 	// after invoking the command.
 	auto const *old_progname = ::getprogname();
 
 	{
-		auto cprogname = std::format("{} {}", ::getprogname(),
-					     command.path());
+		auto cprogname = std::format("{} {}", ::getprogname(), command.path());
 		::setprogname(cprogname.c_str());
 	}
 
 	// Invoke the command see what it returns.  If it's an exit code, just return it.
 	// Otherwise, handle the error.
-	auto ret = command.invoke(argc, argv);
+	auto nrest = static_cast<int>(std::ranges::distance(rest));
+	// Keep the first argument, because getopt() wants it
+	if (nrest < argc)
+		++nrest;
+	auto ret = command.invoke(nrest, argv + (argc - nrest));
 
 	// Restore the old progname.
 	::setprogname(old_progname);