p1.py

#!/usr/bin/env python

import sys
import argparse

def mkvirtualenv_argparser():
    parser = argparse.ArgumentParser()
    parser.add_argument('-p', '--python')
    parser.add_argument('-i', action='append', dest='packages', help='Install \
a package after the environment is created. This option may be repeated.')
    parser.add_argument('-r', dest='requirements', help='Provide a pip \
requirements file to install a base set of packages into the new environment.')
    parser.add_argument('-d', '--dont-activate', action='store_false',
                        default=True, dest='activate', help="After \
                        creation, continue with the existing shell (don't \
                        activate the new environment).")
    return parser


def new_cmd(argv):
    parser = mkvirtualenv_argparser()
    parser.add_argument('-a', dest='project', help='Provide a full path to a \
project directory to associate with the new environment.')

    parser.add_argument('envname')
    args, rest = parser.parse_known_args(argv)
    print(args)

def mkproject_cmd(argv):
    parser = mkvirtualenv_argparser()
    parser.add_argument('envname')
    parser.add_argument(
        '-t', action='append', default=[], dest='templates', help='Multiple \
templates may be selected.  They are applied in the order specified on the \
command line.')
    parser.add_argument(
        '-l', '--list', action='store_true', help='List available templates.')

    args, rest = parser.parse_known_args(argv)
    print(args)

def mktmpenv_cmd(argv):
    parser = mkvirtualenv_argparser()
    args, rest = parser.parse_known_args(argv)
    print(args)

if __name__ == '__main__':
    cmds = dict((cmd[:-4], fun)
                for cmd, fun in globals().items() if cmd.endswith('_cmd'))
    if sys.argv[1:]:
        cmds[sys.argv[1]](sys.argv[2:])

p2.py

#!/usr/bin/env python

import click

@click.group()
def pew():
    pass

mkvenv_command = lambda f: pew.command()(
    click.option('--python', '-p')(
        click.option('-i', multiple=True, help='Install \
        a package after the environment is created. This option may be repeated.')(
            click.option('--requirements', '-r', help='Provide a pip \
            requirements file to install a base set of packages into the new environment.')(
                click.option('activate', '--dont-activate', '-d', is_flag=True, default=True, help="After \
                creation, continue with the existing shell (don't \
                activate the new environment).")(f)))))

@mkvenv_command
@click.option('project', '-a', help='Provide a full path to a \
project directory to associate with the new environment.')
@click.argument('envname')
def new(**kwargs):
    print(kwargs)


@mkvenv_command
@click.argument('envname')
@click.option('templates', '-t', multiple=True, help='Multiple \
templates may be selected.  They are applied in the order specified on the \
command line.')
@click.option('--list', '-l', is_flag=True, help='List available templates.')
def mkproject(**kwargs):
    print(kwargs)

@mkvenv_command
def mktmpenv(**kwargs):
    print(kwargs)

if __name__ == '__main__':
    pew()

p3.py

#!/usr/bin/env python

import click

@click.group()
def pew():
    pass


@pew.command()
@click.option('--python', '-p')
@click.option('-i', multiple=True, help='Install \
a package after the environment is created. This option may be repeated.')
@click.option('--requirements', '-r', help='Provide a pip \
requirements file to install a base set of packages into the new environment.')
@click.option('activate', '--dont-activate', '-d', is_flag=True, default=True, help="After \
creation, continue with the existing shell (don't \
activate the new environment).")
@click.option('project', '-a', help='Provide a full path to a \
project directory to associate with the new environment.')
@click.argument('envname')
def new(**kwargs):
    print(kwargs)


@pew.command()
@click.option('--python', '-p')
@click.option('-i', multiple=True, help='Install \
a package after the environment is created. This option may be repeated.')
@click.option('--requirements', '-r', help='Provide a pip \
requirements file to install a base set of packages into the new environment.')
@click.option('activate', '--dont-activate', '-d', is_flag=True, default=True, help="After \
creation, continue with the existing shell (don't \
activate the new environment).")
@click.argument('envname')
@click.option('templates', '-t', multiple=True, help='Multiple \
templates may be selected.  They are applied in the order specified on the \
command line.')
@click.option('--list', '-l', is_flag=True, help='List available templates.')
def mkproject(**kwargs):
    print(kwargs)

@pew.command()
@click.option('--python', '-p')
@click.option('-i', multiple=True, help='Install \
a package after the environment is created. This option may be repeated.')
@click.option('--requirements', '-r', help='Provide a pip \
requirements file to install a base set of packages into the new environment.')
@click.option('activate', '--dont-activate', '-d', is_flag=True, default=True, help="After \
creation, continue with the existing shell (don't \
activate the new environment).")
def mktmpenv(**kwargs):
    print(kwargs)

if __name__ == '__main__':
    pew()

p4.py

#!/usr/bin/env python

from functools import reduce

import click

@click.group()
def pew():
    pass

def compose(f, g):
    return lambda x: f(g(x))

def arguments(*args):
    return reduce(compose, args, lambda x:x)

def pew_command(*args):
    return compose(pew.command(), arguments(*args))


mkvenv_args = arguments(
    click.option('--python', '-p')
    , click.option('-i', multiple=True, help='Install \
    a package after the environment is created. This option may be repeated.')
    , click.option('--requirements', '-r', help='Provide a pip \
    requirements file to install a base set of packages into the new environment.')
    , click.option('activate', '--dont-activate', '-d', is_flag=True, default=True, help="After \
    creation, continue with the existing shell (don't \
    activate the new environment).")
)

@pew_command(
    mkvenv_args,
    click.option('project', '-a', help='Provide a full path to a \
project directory to associate with the new environment.'),
    click.argument('envname')
)
def new(**kwargs):
    print(kwargs)


@pew_command(
    mkvenv_args,
    click.argument('envname'),
    click.option('templates', '-t', multiple=True, help='Multiple \
    templates may be selected.  They are applied in the order specified on the \
    command line.'),
    click.option('--list', '-l', is_flag=True, help='List available templates.')
)
def mkproject(**kwargs):
    print(kwargs)

@pew_command(mkvenv_args)
def mktmpenv(**kwargs):
    print(kwargs)

if __name__ == '__main__':
    pew()