Build a simple command-line interface from your functions.

Features:

• ✓ Least syntax required: you do not need to "learn a library" to use this
• ✓ keeps it DRY (Don't Repeat yourself):
  • it uses all information available like annotations, default values and docstrings... yet does not require them.
• ✓ Just decorate a function with @cli - that is it - it can now be called as CLI but also remains usable by other functions (unlike the click library)
• ✓ Works with booleans (flags) and lists (multiple args) automatically
• ✓ Standing on the shoulders of giants (i.e. it uses argparse and learnings from others)
• ✓ Prints returned python objects in JSON (unless passing --raw)
• ✓ Colorized output automatically
• ✓ Allows creating executable by using cliche install <mycli>
• ✓ Creates shortcuts, e.g. a variable "long_option" will be usable like --long-option and -l
• ✓ No external dependencies -> lightweight

You want to make a calculator. You not only want its functions to be reusable, you also want it to be callable from command line.

# calculator.py
from cliche import cli

@cli
def add(a: int, b: int):
    print(a + b)

Now let's see how to use it from the command-line:

pascal@archbook:~/calc$ cliche install calc
pascal@archbook:~/calc$ calc add --help

usage: calc add [-h] a b

positional arguments:
  a           |int|
  b           |int|

optional arguments:
  -h, --help  show this help message and exit

thus:

pascal@archbook:~/calc$ calc add 1 10
11

You noticed we ran

cliche install calc

We can undo this with

cliche uninstall calc

Note that installing means that all @cli functions will be detected in the folder, not just of a single file, even after installation. You only have to install once, and on Linux it also adds autocompletion to your CLI if argcomplete has been installed.

from cliche import cli

@cli
def add_or_mul(a_number: int, b_number=10, sums=False):
    """ Adds or multiplies a and b

    :param a_number: the first one
    :param b_number: second one
    :param sums: Sums when true, otherwise multiply
    """
    if sums:
        print(a_number + b_number)
    else:
        print(a_number * b_number)

Help:

Calling it:

pascal@archbook:~/calc$ calc add_or_mul 1
10

pascal@archbook:~/calc$ calc add_or_mul --sum 1
11

pascal@archbook:~/calc$ calc add_or_mul 2 -b 3
6

Check the example files here

• argparse: it is powerful, but you need a lot of code to construct an argparse CLI
• click: you need a lot of decorators to construct a CLI, and not obvious how to use it. It does not keep things DRY. Also, the annotated function is not usable.
• hug (cli): connected to a whole web framework, but gets a lot right
• python-fire: low set up, but annoying traces all the time / ugly design, does not show default values nor types
• cleo: requires too much code/objects to construct