shellac - Interactive Command Interpreter

Shellac

shellac is an alternative to the standard python library cmd which aims to offer an alternative approach to nesting commands.

class shellac.Shellac(completekey='tab', stdin=<_io.TextIOWrapper name='<stdin>' mode='r' encoding='UTF-8'>, stdout=<_io.TextIOWrapper name='<stdout>' mode='w' encoding='UTF-8'>)

Bases: object

An interactive command interpreter. You should never call this class directly. To use it, inherit from this class and implement do_*() methods which map to * commands. Implement child methods of classes defined in your subclass to create subcommands in the interface.

Parameters:

• completekey (readline name of a comlpetion key.) – Key to execute completion
• stdin (File-like object) – Override stdin (defaults to sys.stdin)
• stdout (File-like object) – Override stdout (defaults to sys.stdout)

static call_static(func, *args, **kwargs)

Call a method defined using @staticmethod.

Because we want to define completion functions in their associated class and we want them to be static methods we cannot call them directly. Make sure a callable object is called.

cancel(prompt=False)

Update the shell to indicate a ‘cancel’.

Parameters:prompt (boolean) – If True, force a redraw of the prompt & line.

cmdloop()

Implement an interactive command interpreter which grabs a line of input and passes it to onecmd() until the postcmd() function returns True.

This method will also:

• Execute a preloop() method before starting the interpreter

• Install a complete() readline completer function

• Write the string intro followed by a newline to stdout

  • Read from a list of commands called cmdqueue, or

  • Read from stdin, and

    • Call precmd() with the line as an argument,
    • Call onecmd() with the line as an argument,
    • Call postcmd() with the stop flag and the line as an argument.

• Finally, restore the previous readline completer, if any.

complete

ctrl_c(exc)

Hook method called when Ctrl-C is pressed during execution of loop body.

Can be overridden.

default(line)

Default action for commands with no do_ method.

Can be overridden.

do_EOF(args)

Exit the interactive interpreter.

do_exit(args)

Exit the interactive interpreter.

do_help(args)

Help on help

emptyline()

Method to specify what happens when an empty line is entered.

Can be overridden.

onecmd(line, args='', root=None)

Execute a single command line.

If the given line is False (i.e. empty), call return the result of emptyline(). Thereafter, try to find a chain of do_*() methods and classes which ends with a callable, then return the result of calling it.

Parameters:

• line (string) – line to be executed
• args (string) – used to store ‘current’ part of line during recursion
• root (object) – ‘current’ ‘do_‘ class or method during recursion

postcmd(stop, line)

Hook method executed just after a command dispatch is finished.

Can be overridden.

Parameters:

• stop (None or True) – flag passed in from onecmd() which is usually returned
• line (string) – line executed by onecmd

Returns:

Return True (stop) to cause oneloop() to break

postloop()

Hook method executed once when the cmdloop() method is finished.

Can be overridden

precmd(line)

Hook method executed just before the command line is dispatched.

Can be overridden.

preloop()

Hook method executed once when the cmdloop() method is called.

Can be overridden.

shellac.complete_list(names, token, append_character=' ')

Filter given list which starts with the given string.

Parameters:

• names (list) – list to filter
• token (string) – ‘startswith’ filter token
• append_character (string) – completion character to append (see rl.completion.append_character)

Returns:

generator

shellac.completer(func)

Attach a completion function to the decorated function.

shellac.members(obj, prefix='do_')

Return a list of members of the given class which start with a given prefix.

Parameters:

• obj (class) – Class to inspoect for members of a given prefix.
• prefix (string) – The prefix which members of the given class must start with.

Returns:

list

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