Completion¶
cmd2
adds tab completion of file system paths for all built-in commands
where it makes sense, including:
edit
run_pyscript
run_script
shell
cmd2
also adds tab completion of shell commands to the shell
command.
Additionally, it is trivial to add identical file system path completion to
your own custom commands. Suppose you have defined a custom command foo
by
implementing the do_foo
method. To enable path completion for the foo
command, then add a line of code similar to the following to your class which
inherits from cmd2.Cmd
:
complete_foo = cmd2.Cmd.path_complete
This will effectively define the complete_foo
readline completer method in
your class and make it utilize the same path completion logic as the built-in
commands.
The built-in logic allows for a few more advanced path completion capabilities,
such as cases where you only want to match directories. Suppose you have a
custom command bar
implemented by the do_bar
method. You can enable
path completion of directories only for this command by adding a line of code
similar to the following to your class which inherits from cmd2.Cmd
:
# Make sure you have an "import functools" somewhere at the top
complete_bar = functools.partialmethod(cmd2.Cmd.path_complete, path_filter=os.path.isdir)
Tab Completion Using Argparse Decorators¶
When using one the Argparse-based Decorators, cmd2
provides automatic tab completion of flag names.
Tab completion of argument values can be configured by using one of five
parameters to argparse.ArgumentParser.add_argument()
choices
choices_function
/choices_method
completer_function
/completer_method
See the arg_decorators or colors example for a demonstration of how to
use the choices
parameter. See the argparse_completion example for a
demonstration of how to use the choices_function
and choices_method
parameters. See the arg_decorators or argparse_completion example for a
demonstration of how to use the completer_method
parameter.
When tab completing flags and/or argument values for a cmd2
command using
one of these decorators, cmd2
keeps track of state so that once a flag has
already previously been provided, it won’t attempt to tab complete it again.
When no completion results exists, a hint for the current argument will be
displayed to help the user.
CompletionItem For Providing Extra Context¶
When tab completing things like a unique ID from a database, it can often be
beneficial to provide the user with some extra context about the item being
completed, such as a description. To facilitate this, cmd2
defines the
CompletionItem
class which can be returned from any of the 4 completion
functions: choices_function
, choices_method
, completion_function
,
or completion_method
.
-
class
cmd2.argparse_custom.
CompletionItem
(value: object, desc: str = '', *args, **kwargs)¶ Completion item with descriptive text attached
See header of this file for more information
See the argparse_completion example or the implementation of the built-in set command for demonstration of how this is used.