Fix generic help and usage of invalid subcommands in aliases

Plain 'help' would crash the column UI, as would the usage of an invalid
command in an alias.

This case should be handled properly, as the CLI and Prompt mode do.

For this purpose, the generic help text was extracted, such that it can
be printed in column mode (and also in prompt mode, while I was at it).

topydo/ui/CLIApplicationBase.py

@@ -29,25 +29,7 @@ MAIN_OPTS = "ac:C:d:ht:v"
 MAIN_LONG_OPTS = ('version')
 READ_ONLY_COMMANDS = ('List', 'ListContext', 'ListProject')
 
-
-def usage():
-    """ Prints the command-line usage of topydo. """
-
-    print("""\
-Synopsis: topydo [-a] [-c <config>] [-C <colormode>] [-d <archive>] [-t <todo.txt>] subcommand [help|args]
-          topydo -h
-          topydo -v
-
--a : Do not archive todo items on completion.
--c : Specify an alternative configuration file.
--C : Specify color mode (0 = disable, 1 = enable 16 colors,
-     16 = enable 16 colors, 256 = enable 256 colors, auto (default))
--d : Specify an alternative archive file (done.txt)
--h : This help text
--t : Specify an alternative todo file
--v : Print version and exit
-
-Available commands:
+GENERIC_HELP="""Available commands:
 
 * add
 * append (app)
@@ -66,7 +48,26 @@ Available commands:
 * tag
 
 Run `topydo help <subcommand>` for command-specific help.\
-""")
+"""
+
+def usage():
+    """ Prints the command-line usage of topydo. """
+
+    print("""\
+Synopsis: topydo [-a] [-c <config>] [-C <colormode>] [-d <archive>] [-t <todo.txt>] subcommand [help|args]
+          topydo -h
+          topydo -v
+
+-a : Do not archive todo items on completion.
+-c : Specify an alternative configuration file.
+-C : Specify color mode (0 = disable, 1 = enable 16 colors,
+     16 = enable 16 colors, 256 = enable 256 colors, auto (default))
+-d : Specify an alternative archive file (done.txt)
+-h : This help text
+-t : Specify an alternative todo file
+-v : Print version and exit
+
+""" + GENERIC_HELP)
 
 def write(p_file, p_string):
     """

topydo/ui/columns/Main.py

@@ -32,7 +32,7 @@ from topydo.lib.Utils import get_terminal_size
 from topydo.lib.View import View
 from topydo.lib.TodoFileWatched import TodoFileWatched
 from topydo.lib import TodoList
-from topydo.ui.CLIApplicationBase import CLIApplicationBase, error
+from topydo.ui.CLIApplicationBase import CLIApplicationBase, error, GENERIC_HELP
 from topydo.ui.columns.CommandLineWidget import CommandLineWidget
 from topydo.ui.columns.ConsoleWidget import ConsoleWidget
 from topydo.ui.columns.KeystateWidget import KeystateWidget
@@ -301,6 +301,10 @@ class UIApplication(CLIApplicationBase):
                 'Error: {}. Check your aliases configuration.'.format(cerr))
             return
 
+        if subcommand is None:
+            self._print_to_console(GENERIC_HELP)
+            return
+
         env_args = (self.todolist, p_output, self._output, self._input)
         ids = None
 

topydo/ui/prompt/Prompt.py

@@ -20,7 +20,7 @@ import os.path
 import shlex
 import sys
 
-from topydo.ui.CLIApplicationBase import CLIApplicationBase, error, usage
+from topydo.ui.CLIApplicationBase import CLIApplicationBase, error, GENERIC_HELP
 from topydo.ui.prompt.TopydoCompleter import TopydoCompleter
 from prompt_toolkit.shortcuts import prompt
 from prompt_toolkit.history import InMemoryHistory
@@ -94,7 +94,7 @@ class PromptApplication(CLIApplicationBase):
                 if self._execute(subcommand, args) != False:
                     self._post_execute()
             except TypeError:
-                usage()
+                print(GENERIC_HELP)
 
 
 def main():