built-in validators

The following are built in validators in records

class ValidationToken

A base class for all object that should be interpreted as validators

class AssertValidation(ValidationToken, ABC)

A validation token to check that a condition is upheld

__init__(*, err: Union[str, Exception] = 'validation failed', warn: Union[bool, logging.Logger] = False)
Parameters

  • err – the error or warning to raise if the condition is not upheld.

  • warn – whether to issue a warning instead if raising an error. Can also be an instance of a Logger, to specify the logger to warn with.

abstract assert_(v) → bool
Parameters

v – the value to check.

Returns

Whether the condition is upheld for v.

class AssertCallValidation(AssertValidation)

An assertion validation token to call arbitrary functions

__init__(func: Callable[[T], bool], **kwargs)
Parameters

  • func – the assertion function

  • kwargs – forwarded to AssertValidation.__init__

class CallValidation(AssertValidation)

An validation token to call arbitrary functions

__init__(func: Callable[[…], T], *args, **kwargs)
Parameters

  • func – The callable to use as the validation callback.

  • args – Optional positional arguments to pass to func, after the validation argument.

  • kwargs – Optional keyword arguments to pass to func.

Note

calling CallValidation with args or kwargs is akin to calling it with a functools.partial() as func.

>>> CallValidation(foo, a, b, c=d)
>>> # is equivalent to
>>> CallValidation(lambda v: foo(v, a, b, c=d))
class Clamp(ValidationToken)
A validator class that constrains the value to be between two bounds, bringing it to the nearest bound if it

falls outside.

__init__(ge: Any = <records.fillers.builtin_validators._Least object>, le: Any = <records.fillers.builtin_validators._Greatest object>, **kwargs)
Parameters

  • ge – the lower bound, defaults to no lower bound

  • le – the upper bound, defaults to no upper bound

class Cyclic(ValidationToken)
A validator class that constrains the value to be between two bounds, bringing it to the equivalent position as

though the domain is cyclic. Useful for angles and time of day.

__init__(minimum, maximum, **kwargs)
Parameters

  • minimum – the inclusive lower bound

  • maximum – the exclusive upper bound.

class Within(AssertValidation)

An assertion validation that raises an error if the value falls outside of bounds.

__init__(ge: Any = <records.fillers.builtin_validators._Least object>, lt: Any = <records.fillers.builtin_validators._Greatest object>, g_eq=True, l_eq=False, **kwargs)
Parameters

  • ge – the lower bound, defaults to no lower bound

  • lt – the upper bound, defaults to no upper bound

  • g_eq – whether the lower bound is inclusive, defaults to True.

  • l_eq – whether the upper bound is inclusive, defaults to False.

  • kwargs – forwarded to AssertValidation

class FullMatch(AssertValidation)

An assertion validation that raises an error if the value does not match a regex pattern.

__init__(pattern: Union[Pattern, str, bytes], **kwargs)
Parameters

  • pattern – either a compiled pattern or an uncompiled string or bytestring

  • kwargs – forwarded to AssertValidation

Note

pattern will be compiled in accordance to records.extras.re

class Truth(AssertValidation)

An assertion validation that raises an error if the value does not evaluate as True.

__init__(*, err: Union[str, Exception] = 'validation failed', warn: Union[bool, logging.Logger] = False)
Parameters

  • err – the error or warning to raise if the condition is not upheld.

  • warn – whether to issue a warning instead if raising an error. Can also be an instance of a Logger, to specify the logger to warn with.