Canonicalise Args And Kwargs To Kwarg-canonical Form

I've asked a similar question here for posarg-canonical form. Any possible args should be converted to keyword-form, with the defaults being omitted based on the result of the is o

Solution 1:

You can use the following function - you basically move arguments which have a default value into whatever was in **kwargs (if it's not actually assigned to its own default value):

import inspect

def canonicalize(f, *args, **kwargs):
    sig = inspect.signature(f)
    bargs = sig.bind(*args, **kwargs)
    # Pop out the named kwargs variable defaulting to {}
    ret_kwargs = bargs.arguments.pop(inspect.getfullargspec(f).varkw, {})
    # For all possible signature values
    for k, v in sig.parameters.items():
        # If the name exists in the bound arguments and has a default value
        if k in bargs.arguments and v.default is not inspect.Parameter.empty:
            # Remove from the bound arguments dict
            val = bargs.arguments.pop(k)
            # If the value isn't the same as the default value add it to ret_kwargs
            if val is not v.default:
                ret_kwargs[k] = val

    # bargs.args here will be made up of what's left in bargs.arguments
    return bargs.args, ret_kwargs