1 files changed, 22 insertions, 20 deletions

diff --git a/nihil.cli/dispatch_command.cc b/nihil.cli/dispatch_command.cc
index 7b4cf39..6cf7f05 100644
--- a/nihil.cli/dispatch_command.cc
+++ b/nihil.cli/dispatch_command.cc
@@ -2,6 +2,7 @@
 module;
 
 #include <stdlib.h> // getprogname, NOLINT
+#include <sysexits.h> // EX_USAGE
 #include <unistd.h> // getopt
 
 module nihil.cli;
@@ -11,6 +12,15 @@ import nihil.core;
 
 namespace nihil {
 
+namespace {
+// Print this node's children in a form useful to humans.
+auto print_commands(command_tree_node const &node) -> void
+{
+	for (auto &&child : node.children())
+		std::print(std::cerr, "  {}\n", child.command().path());
+}
+}
+
 auto dispatch_command(int argc, char **argv) -> int
 {
 	auto tree = build_command_tree();
@@ -20,52 +30,44 @@ auto dispatch_command(int argc, char **argv) -> int
 	// 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.
+	// find() never returns nullptr; at worst it will return the root node.
 	auto const *node = tree.find(argc, argv);
-
-	// Get the command_node.
 	auto const &command = node->command();
 
 	// Reset getopt(3) for the command, in case main() used it already.
 	optreset = 1;
 	optind = 1;
 
-	/*
-	 * Set the program name to the existing progname plus the full path
-	 * to the command being invoked; this makes error messages nicer.
-	 */
+	// 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());
+					     command.path());
 		::setprogname(cprogname.c_str());
 	}
 
-	// Invoke the command see what it returns.
-	auto ret = command->invoke(argc, argv);
+	// 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);
 
 	// Restore the old progname.
 	::setprogname(old_progname);
 
-	// If the command produced an exit code, return it.
 	if (ret)
 		return *ret;
 
-	/*
-	 * We have special handling for some errors.
-	 */
-
 	// Incomplete command: print the list of valid commands at this node.
 	if (ret.error() == errc::incomplete_command) {
-		std::print(std::cerr, "{}: usage:\n", ::getprogname());
-		node->print_commands();
-		return 1;
+		std::println(std::cerr, "{}: usage:", ::getprogname());
+		print_commands(*node);
+		return EX_USAGE;
 	}
 
 	// We didn't recognise the error, so just print it and exit.
-	std::print(std::cerr, "{}\n", ret.error());
+	std::println(std::cerr, "{}", ret.error());
 	return 1;
 }