Python创建命令行应用的工具 tools for command line application in python
工具1：Docopt
这个工具是根据模块的文档注释来确定参数的。注释分为两部分：Usage, option。
\```
Usage:
naval_fate ship new <name>...
naval_fate ship <name> move <x> <y> [--speed=<kn>]
naval_fate ship shoot <x> <y>
naval_fate mine (set|remove) <x> <y> [--moored|--drifting]
naval_fate -h | --help
naval_fate --version
Options:
-h --help Show this screen.
--version Show version.
--speed=<kn> Speed in knots [default: 10].
--moored Moored (anchored) mine.
--drifting Drifting mine.
\```
指定了这些参数，就可以在程序中调用相关参数，使用get方法。
arguments = docopt(__doc__, version=myapp 1.0')
if arguments.get("add"):
print("添加成功")
elif arguments.get("delete"):
print("删除成功")
工具2：click
https://click.palletsprojects.com/en/7.x/
click是使用装饰器，根据这些来自动生成帮助文件。
import click
@click.command()
@click.option('--count', default=1, help='Number of greetings.')
@click.option('--name', prompt='Your name',
help='The person to greet.')
def hello(count, name):
"""Simple program that greets NAME for a total of COUNT times."""
for x in range(count):
click.echo('Hello %s!' % name)
if __name__ == '__main__':
hello()
这样，帮助文件就生成了：
$ python hello.py --help
Usage: hello.py [OPTIONS]
Simple program that greets NAME for a total of COUNT times.
Options:
--count INTEGER Number of greetings.
--name TEXT The person to greet.
--help Show this message and exit.
