Keyword-only parameters

sigtools provides two decorators to emulate keyword-only parameters:

sigtools.modifiers.autokwoargs(func=None, *, exceptions=())

Converts all parameters with default values to keyword-only parameters:

from sigtools.modifiers import autokwoargs


@autokwoargs
def func(arg, opt1=False, opt2=False, *rest):
    print(arg, rest, opt1, opt2)


func(1, 2, 3)
# 1 (2, 3) False False

func(1, 2, opt2=True)
# -> 1 (2,) False True

In the example above, the opt1 and opt2 parameters are ‘skipped’ by positional arguments and can only be set using named arguments (opt2=True).

If you wish to prevent parameters that have a default from becoming keyword-only, you can use the exceptions= parameter:

@autokwoargs(exceptions=['arg2'])
def func(arg1, arg2=42, opt1=False, opt2=False):
    print(arg1, arg2, opt1, opt2)

func(1, 2, opt1=False)
# 1 2 False False

If you wish to pick individual parameters to convert, use sigtools.modifiers.kwoargs. This module also allows you to add function annotations using the annotate decorator.