easytypes 0.1.4

Easy declaration of data structures with runtime type checking

easytypes

Easy typed structures for Python with optional field checking and runtime type checking. Based on class decorators and typeguard package for type checking.

What does the package implement

from easytypes import easy_type_decorator, safe_type, fast_type, unlimited_type
from easytypes import EasyTypesException
from easytypes import AttributeRequired, AttributeNotAllowed, AttributeTypeError
from easytypes import Required
from easytypes import disable_all_checks, enable_all_checks

How to define a simple data class

from easytypes import easy_type_decorator, safe_type, fast_type, unlimited_type
from easytypes import EasyTypesException
from easytypes import AttributeRequired, AttributeNotAllowed, AttributeTypeError
from easytypes import Required
from easytypes import disable_all_checks, enable_all_checks

@safe_type  # You cannot: add new attrs; not set (or delete) the required attrs; assign wrong types
class A:
    a: int  # Type checking, not required, no default value
    b: str = '5'  # Type checking, not required, the default value is '5'
    c: float = Required()  # Type checking, required, no default value
    d: Tuple[int, int] = Required(2, 3)  # Type checking, required, the default value is (2, 3)

...and how does the class work

va = A(a=2, b='b', c=1.0, d=(2,4))  # Ok
assert va.a == 2
va.a = 5
assert va.a == 5
va = A(c=1.0)  # Ok, using default values
va = A(c=1.0, q=2)  # raises AttributeNotAllowed 
va.q = 0  # raises AttributeNotAllowed
va.a = '5'  # raises AttributeTypeError (a should be int)
va = A(c='c')  # raises AttributeTypeError (c should be float)
va = (b='c')  # raises AttributeRequired (a is missing)

How to extend a class

@safe_type
class B(A):
    e: str = 5  # Is added to the fields defined in A

...and how to redefine a field

@safe_type
class C(A):
    a: int = 5  # Not recomended and not prohibited

How to disable all the checks at runtime

disable_all_checks()  # Does not affect all the previously created classes, so put it before the class declaration

...and how to re-enable them

enable_all_checks()  # Does not affect all the previously created classes, so put it before the class declaration

The other class decorators

unlimited_type  # Allows to add the attributes that are not declared at the class level
fast_type  # No checks at all, just a constructor implemetation accepting the attributes

...and how to get a customized decorator

easy_type_decorator(chk_required=True, chk_allowed=True, chk_types=True)  # Allows to activate only the desired checks