Select destination variable for click parser

Question

I'm wondering how to override destination variable for the click.option (Click lib). For example in such piece of code

import click

@click.command()
@click.option('--output', default='data')
def generate_data(output_folder):
    print(output_folder)

So I want to use --output flag but pass its value to output_folder argument, kinda this: @click.option('--output', default='data', dest='output_folder')? Is there is such an ability in click? I know that argparse allow such a behaviour.

Fushih

Answer 1

Yes, see the section in the click documentation on parameter names, which covers both options and arguments.

If a parameter is not given a name without dashes, a name is generated automatically by taking the longest argument and converting all dashes to underscores. For an option with ('-f', '--foo-bar'), the parameter name is foo_bar. For an option with ('-x',), the parameter is x. For an option with ('-f', '--filename', 'dest'), the parameter is called dest.

Here's your example:

from __future__ import print_function
import click

@click.command()
@click.option('--output', 'data')
def generate_data(data):
    print(data)

if __name__ == '__main__':
    generate_data()

Running it:

$ python2.7 stack_overflow.py --output some_output
some_output

Dillion

Keep in mind that for Arguments this won't work, and instead throws an Exception: TypeError: Arguments take exactly one parameter declaration, got 2. – Massenet