degesch: print usage on command syntax failure

degesch.c

@@ -2589,7 +2589,7 @@ log_outcoming_notice (struct app_context *ctx,
 
 // --- User input handling -----------------------------------------------------
 
-static void handle_command_help (struct app_context *, char *);
+static bool handle_command_help (struct app_context *, char *);
 
 /// Cuts the longest non-whitespace portion of text and advances the pointer
 static char *
@@ -2642,12 +2642,12 @@ server_command_check (struct app_context *ctx, const char *action)
 	return false;
 }
 
-static void
+static bool
 handle_command_buffer (struct app_context *ctx, char *arguments)
 {
 	char *action = cut_word (&arguments);
 	if (try_handle_buffer_goto (ctx, action))
-		return;
+		return true;
 
 	struct buffer *buffer = NULL;
 
@@ -2684,19 +2684,19 @@ handle_command_buffer (struct app_context *ctx, char *arguments)
 		{
 			buffer_send_error (ctx, ctx->global_buffer,
 				"%s: %s", "No such buffer", which);
-			return;
+			return true;
 		}
 		if (buffer == ctx->global_buffer)
 		{
 			buffer_send_error (ctx, ctx->global_buffer,
 				"Can't close the global buffer");
-			return;
+			return true;
 		}
 		if (buffer == ctx->server_buffer)
 		{
 			buffer_send_error (ctx, ctx->global_buffer,
 				"Can't close the server buffer");
-			return;
+			return true;
 		}
 
 		if (buffer == ctx->current_buffer)
@@ -2704,41 +2704,34 @@ handle_command_buffer (struct app_context *ctx, char *arguments)
 		buffer_remove (ctx, buffer);
 	}
 	else
-	{
-		// TODO: show usage (or do something else?)
-	}
+		return false;
+
+	return true;
 }
 
-static void
+static bool
 handle_command_msg (struct app_context *ctx, char *arguments)
 {
 	if (!server_command_check (ctx, "send messages"))
-		return;
-
+		return true;
 	if (!*arguments)
-	{
-		// TODO: show usage or something
-		return;
-	}
+		return false;
 
 	char *target = cut_word (&arguments);
 	if (!*arguments)
 		buffer_send_error (ctx, ctx->server_buffer, "No text to send");
 	else
 		SEND_AUTOSPLIT_PRIVMSG (ctx, target, arguments);
+	return true;
 }
 
-static void
+static bool
 handle_command_query (struct app_context *ctx, char *arguments)
 {
 	if (!server_command_check (ctx, "send messages"))
-		return;
-
+		return true;
 	if (!*arguments)
-	{
-		// TODO: show usage or something
-		return;
-	}
+		return false;
 
 	char *target = cut_word (&arguments);
 	if (irc_is_channel (ctx, target))
@@ -2750,28 +2743,26 @@ handle_command_query (struct app_context *ctx, char *arguments)
 		buffer_activate (ctx, irc_get_or_make_user_buffer (ctx, target));
 		SEND_AUTOSPLIT_PRIVMSG (ctx, target, arguments);
 	}
+	return true;
 }
 
-static void
+static bool
 handle_command_notice (struct app_context *ctx, char *arguments)
 {
 	if (!server_command_check (ctx, "send messages"))
-		return;
-
+		return true;
 	if (!*arguments)
-	{
-		// TODO: show usage or something
-		return;
-	}
+		return false;
 
 	char *target = cut_word (&arguments);
 	if (!*arguments)
 		buffer_send_error (ctx, ctx->server_buffer, "No text to send");
 	else
 		SEND_AUTOSPLIT_NOTICE (ctx, target, arguments);
+	return true;
 }
 
-static void
+static bool
 handle_command_quit (struct app_context *ctx, char *arguments)
 {
 	if (ctx->irc_fd != -1)
@@ -2782,13 +2773,14 @@ handle_command_quit (struct app_context *ctx, char *arguments)
 			irc_send (ctx, "QUIT :%s", PROGRAM_NAME " " PROGRAM_VERSION);
 	}
 	initiate_quit (ctx);
+	return true;
 }
 
-static void
+static bool
 handle_command_join (struct app_context *ctx, char *arguments)
 {
 	if (!server_command_check (ctx, "join"))
-		return;
+		return true;
 
 	if (*arguments)
 		// TODO: check if the arguments are in the form of
@@ -2809,13 +2801,14 @@ handle_command_join (struct app_context *ctx, char *arguments)
 			// TODO: send the key if known
 			irc_send (ctx, "JOIN %s", ctx->current_buffer->channel->name);
 	}
+	return true;
 }
 
-static void
+static bool
 handle_command_part (struct app_context *ctx, char *arguments)
 {
 	if (!server_command_check (ctx, "part"))
-		return;
+		return true;
 
 	if (*arguments)
 		// TODO: check if the arguments are in the form of "channel(,channel)*"
@@ -2834,21 +2827,23 @@ handle_command_part (struct app_context *ctx, char *arguments)
 		else
 			irc_send (ctx, "PART %s", ctx->current_buffer->channel->name);
 	}
+	return true;
 }
 
-static void
+static bool
 handle_command_quote (struct app_context *ctx, char *arguments)
 {
 	if (!server_command_check (ctx, "quote"))
-		return;
+		return true;
 
 	irc_send (ctx, arguments);
+	return true;
 }
 
 static struct command_handler
 {
 	const char *name;
-	void (*handler) (struct app_context *ctx, char *arguments);
+	bool (*handler) (struct app_context *ctx, char *arguments);
 	const char *description;
 	const char *usage;
 }
@@ -2898,14 +2893,14 @@ g_command_handlers[] =
 	  "command" },
 };
 
-static void
+static bool
 handle_command_help (struct app_context *ctx, char *arguments)
 {
 	if (*arguments)
 	{
 		char *command = cut_word (&arguments);
 		// TODO: search for the command and show specific help
-		return;
+		return true;
 	}
 
 	buffer_send_status (ctx, ctx->global_buffer, "Commands:");
@@ -2917,6 +2912,7 @@ handle_command_help (struct app_context *ctx, char *arguments)
 		buffer_send_status (ctx, ctx->global_buffer,
 			"    Arguments: %s", iter->usage);
 	}
+	return true;
 }
 
 static int
@@ -2970,11 +2966,12 @@ process_user_command (struct app_context *ctx, char *command)
 		return;
 
 	struct command_handler *handler = str_map_find (&partial, name);
-	if (handler)
-		handler->handler (ctx, command);
-	else
+	if (!handler)
 		buffer_send_error (ctx, ctx->global_buffer,
 			"%s: %s", "No such command", name);
+	else if (!handler->handler (ctx, command))
+		buffer_send_error (ctx, ctx->global_buffer,
+			"%s: /%s %s", "Usage", handler->name, handler->usage);
 }
 
 static void