typing_ex 0.1.32

A package for extended built-in types

typing_ex

A python package for extended typing (python 3.8+)

Notice: yet to be heavily tested, only simple tests are passed.

Frozen frozen.py

• FrozenList: Immutable list
• FrozenDict: Immutable dict
• frozen_copy: Create frozen copy of supported types (Sequence, Set, Mapping)

TypeInfo type_info.py

• TypeInfo: provide type information and run-time type checking
  • TypeInfo[...].type: type
  • TypeInfo[...]..origin: unsubscripted type
  • TypeInfo[...]..args: type arguments
  • TypeInfo[...]..name: name of type (including arguments)
  • TypeInfo.check_union(t1, t2): check if union type t1 fulfill union type t2
  • TypeInfo[...].check_value(value): check if value matches the type in type info
  • TypeInfo[...].is_*: check if type is _

# type_a | type_b is only supported when python >= 3.10
TypeInfo[list[int | str]].name # list[int | str]
TypeInfo.check_union(int | str, str | int) # True
TypeInfo.check_union(int, int | str) # True
TypeInfo.check_union(int, Union[int | str]) # True
TypeInfo.check_union(Union[int, str], Union[str, int]) # True
TypeInfo.check_union(int | str, str) # False
TypeInfo.check_union(int | str, int | float) # False
TypeInfo.check_union(Union[int, str], int | float) # False
TypeInfo[int | str].check_value(123) # True
TypeInfo[list[int | str]].check_value([1, "2", 3]) # True
TypeInfo[list[int]].check_value([1, "2", 3]) # False
TypeInfo[list[int | str]].check_value([1.0, "2", 3]) # False

TypedDefaultDict typed_defaultdict.py

• TypedDefaultDict: combining features of TypedDict and defaultdict with type checking in __init__, __setitem__, __setattr__ and update

  • TypedDefaultDict.schema: the schema dictionary: MappingProxyType[str, NamedTuple[default: Any, type:TypeInfo]]
  • TypedDefaultDict.on_get_unknown_property: called on getting unknown property
  • TypedDefaultDict.on_set_unknown_property: called on setting unknown property
  • TypedDefaultDict.set: set a property to a value without property check and type check

• Attributes without type annotation or starting with underscore "_" will be treated as class variables

• You can override on_get_unknown_property and on_set_unknown_property to override the behavior when getting or setting unknown property, raises UnknownPropertyError by default.

  • on_get_unknown_property(k): either raise an error or return a value based on k
  • on_set_unknown_property(k, v): raise an error / return a value based on (k, v) to set k to new value / process and return None to ignore

• Good for writing schema as a class for JSON/YAML/XML/etc. data which provides both static and runtime type checking.

class TestDict(TypedDefaultDict):
    foo: str | None = "bar" # default value is "bar"
    bar: list[str] = [] # default value is []

testdict = TestDict()
testdict["foo"] # "bar"
testdict.foo # "bar"
testdict.bar # []
# check type and unexpected properties on assignment
testdict.abcd # raises `UnknownPropertyError`
testdict.foo = 123 # raises `PropertyValueError`
testdict = TestDict( # raises `PropertyValueError`
    foo = 123
)

# example of loading from JSON
with open("test.json", "r") as f:
    # will also check on init
    testdict = TestDict(json.load(f))

# example overriding on_*_unknown_property
class TestDict(TypedDefaultDict):
    foo: str = "foo"
    bar: str = "bar"

    _extra_props: dict[str, Any] = {} # class variable

    @override
    def on_get_unknown_property(self, k) -> Any:
        raise AttributeError(k)

    @override
    def on_set_unknown_property(self, k: str, v: Any) -> Any:
        self._extra_props[k] = v
        return None

EnumEx enum_ex.py

• EnumEx is a Enum like class that support enum aliasing (keeping same value but different name).

  • EnumEx.__iter__: a generator of all non-alias enum instances.

  • EnumEx.names: a tuple of all enum names.

  • EnumEx.values: a tuple of all enum values.

  • EnumEx.enums: a tuple of all enum instances.

  • EnumEx.value_type: returns __value_type__ if defined, int otherwise.

  • EnumEx.X.value: value of enum X

  • EnumEx.X.name: name of enum X (i.e. X)

  • EnumEx.X_ALIAS.orig_name: original name of enum X_ALIAS (i.e. X)

  • EnumEx.X_ALIAS.origin: origin enum of X_ALIAS (i.e. EnumEx.X)

class AliasedEnum(EnumEx):
    __value_type__ = str # default is int
    foo = "1"
    foo2 = foo # alias
    bar = "2"
    bar2 = bar # alias

foo.name # "foo"
foo.value # 1

foo2.name # "foo2"
foo2.value # 1
foo2.orig_name # "foo"

bar2.name # "bar2"
bar2.value # 2
bar2.orig_name # "bar"