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A Cmd-based framework for writing line-oriented command interpreters.

Project description

enhterm

enhterm is an open source, MIT licensed, Cmd-based framework for writing command interpreters.

Build Status Documentation Status

enhterm provides a class that extends cmd.Cmd and which is also intended to be inherited by a user class, with the end purpose being to create a shell.

Functionality provided by this package is split among mixins, allowing you to construct your own base class if EnhTerm is not suitable.

As with cmd.Cmd, the class constructed as described above can be used like so:

from enhterm import EnhTerm

from enhterm.provider.parser.argparser import ArgParser
from enhterm.provider.parser.argparser.commands import register_commands
from enhterm.provider.stream_provider import StreamProvider

# The stream provider by default reads the input from console.
provider = StreamProvider()

# The text entered by the user then needs to be interpreted.
# Here we use an interpreter based on argparse.
provider.parser = ArgParser(provider=provider)
subparsers = provider.parser.add_subparsers()

# Add built-in commands.
register_commands(subparsers)

# Define you own handler.
def do_add(command, integers):
    return sum(integers)

# Add this command to the argparse library.
parser_add = subparsers.add_parser('add')
parser_add.add_argument(
     'integers', metavar='int', nargs='+', type=int,
     help='integers to be summed (space separated list)')
parser_add.set_defaults(func=do_add)


# Construct the terminal.
class MyShell(EnhTerm):
    """
    Simple terminal.

    Has a command that can add integers and another one
    that quits the interpreter.
    """
    def __init__(self):
        super().__init__(providers=provider)


if __name__ == '__main__':
    print("Type 'add 1 2 3 4 5 6 7 8 9' and you should get back 45")
    print("Type '-h' to get back the usage")
    MyShell().cmd_loop()

Install

pip install enhterm

You can also download/clone the source, in which case you have to:

git clone https://github.com/pyl1b/enhterm.git
python setup.py install

To contribute a patch clone the repo, create a new branch, install in develop mode:

python setup.py develop

What is included

Each of the elements below are implemented in a distinct "mixin" class, which mean that you can create your own combination using EnhTerm class as a template.

Command

Allows python strings to be executed as if the user typed the input at the prompt. This is the base for executing commands in a file.

Exit

Provides the exit command that terminates command loop.

Help

Provides the help command which prints information about the use of the command while accounting for custom commands and shortcuts.

Log Level

Allows changing logging verbosity by issuing commands like set loglevel debug.

Macro

Can record, remove, list and execute previously recorded commands.

Messages

Does not expose any commands but provides the class with a standardized way of issuing messages distinct from the logging mechanism.

Run

Allows executing multiple commands from a string or from a file.

Sub-commands

Commands are usually identified by using the first word the user types. This mixin allows for a more natural way of issuing commands like new macro instead of macro new. Other mixins then add subcommands in their __init__ method.

Project details


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