"""Shared parameter validator factories."""
import re
from functools import lru_cache
from typing import Any, Callable, Dict, List, Pattern, Tuple, Union
AliasContainerType = Union[Dict[Any, Any], List[Any], Tuple[Any, ...]]
AliasConversionFunction = Callable[[Any], Any]
noop_conversion: AliasConversionFunction = lambda value: value
[docs]
@lru_cache()
def convert_to_selection(index: int) -> Callable[[AliasContainerType], Any]:
"""Create a validator to access a single value from an index-able attribute.
:param index: The index to access on the attribute's value.
:returns: A function to access an attribute's indexed value.
"""
return lambda value: value[index]
[docs]
@lru_cache()
def create_is_equal(
target: Any,
conversion_function: AliasConversionFunction = noop_conversion,
) -> Callable[[Any], bool]:
"""Create a validator to perform an equality test on an attribute.
:param target: The value the attribute value will be compared to.
:param conversion_function: Transform the attribute value before comparison.
:returns: A function to check an attribute's value for equality.
"""
return lambda value: conversion_function(value) == target
[docs]
@lru_cache()
def create_is_greater_than_or_equal(
threshold: Union[float, int],
conversion_function: AliasConversionFunction = noop_conversion,
) -> Callable[[Any], bool]:
"""Create a validator to perform a >= test on an attribute.
:param threshold: The value the attribute value will be compared to.
:param conversion_function: Transform the attribute value before comparison.
:returns: A function to check if an attribute's value is >= the target.
"""
return lambda value: conversion_function(value) >= threshold
[docs]
@lru_cache()
def create_is_in(container: Tuple[Any, ...]) -> Callable[[Any], bool]:
"""Create a validator to check if an attribute is in set of values.
:param container: A tuple of values the attribute can be equal to.
:returns: A function to check if an attribute's value is in a set of values.
"""
return lambda value: value in container
[docs]
@lru_cache()
def create_is_less_than_or_equal(
threshold: Union[float, int],
conversion_function: AliasConversionFunction = noop_conversion,
) -> Callable[[Any], bool]:
"""Create a validator to perform a <= test on an attribute.
:param threshold: The value the attribute value will be compared to.
:param conversion_function: Transform the attribute value before comparison.
:returns: A function to check if an attribute's value is <= the target.
"""
return lambda value: conversion_function(value) <= threshold
[docs]
@lru_cache()
def create_matches_regex(pattern: Pattern[Any]) -> Callable[[Any], bool]:
"""Create a validator to perform a regex match on an attribute.
:param pattern: The regex pattern to attempt to match the attribute with.
:returns: A function to check an attribute's value against a regex pattern.
"""
return lambda value: bool(re.match(pattern, value))