mrpro.operators.EndomorphOperator.ParamSpec

class mrpro.operators.EndomorphOperator.ParamSpec(name, *, bound=None, covariant=False, contravariant=False)

Bases: _Final, _Immutable, _BoundVarianceMixin, _PickleUsingNameMixin

Parameter specification variable.

Usage:

P = ParamSpec('P')

Parameter specification variables exist primarily for the benefit of static type checkers. They are used to forward the parameter types of one callable to another callable, a pattern commonly found in higher order functions and decorators. They are only valid when used in Concatenate, or as the first argument to Callable, or as parameters for user-defined Generics. See class Generic for more information on generic types. An example for annotating a decorator:

T = TypeVar('T')
P = ParamSpec('P')

def add_logging(f: Callable[P, T]) -> Callable[P, T]:
    '''A type-safe decorator to add logging to a function.'''
    def inner(*args: P.args, **kwargs: P.kwargs) -> T:
        logging.info(f'{f.__name__} was called')
        return f(*args, **kwargs)
    return inner

@add_logging
def add_two(x: float, y: float) -> float:
    '''Add two numbers together.'''
    return x + y

Parameter specification variables can be introspected. e.g.:

P.__name__ == ‘P’

Note that only parameter specification variables defined in global scope can be pickled.

__init__(name, *, bound=None, covariant=False, contravariant=False)

Methods

__init__(name, *[, bound, covariant, ...])

Attributes

args
kwargs