Stop using callable objects - Fixes: #95 (#136)

* migrate casting from callable objects to normal functions

* migrate cast to date function

* delete old test files

* rename new test files

* use new normal functions in get_casting_function()

* linting

* Move iso functions from callable objects to normal functions

* bump version and add changelog

* Fixes from review: @ChameleonTartu

* Update changelog based on feedback from @ChameleonTartu

* Do major version bump and update changelog

CHANGELOG.md

@@ -9,6 +9,17 @@
 
 ## Latest Changes
 
+## Version 3.0.0 @dataclass from attr bug and no more callable objects.
+
+We were using `@dataclass` decorator from attr, which caused kaiba not to run when used in an environment that did not have attr installed. Thanks to @ChameleonTartu for finding and reporting the bug.
+
+Non-private code has been changed which is why this is a major version. In the future we will make sure to have clearer line between what is private internal kaiba code and what is the interface that users will use. 
+
+### Internal
+
+* We are now callable object free. From now on, we will only use functions. 
+
+
 ## Version 2.0.0 Upgrade dependencies, support python 3.10, 3.11
 
 This major version bump was needed because we upgrade `pydantic` to version 2 from version 1. This changed a lot of error messages in schema validation. If anyone was depending on those, it would break their code. In the same update we are updating a lot of other dependencies too. Most importantly going from `returns` 0.14 to 0.22. This might mean we can make the functional code look better in the future. We are also now support python 3.10 and 3.11 and test them like we do 3.8 and 3.9.

kaiba/casting/__init__.py

@@ -0,0 +1,20 @@
+from typing import Callable
+
+from returns.result import safe
+
+from kaiba.casting._cast_to_date import cast_to_date
+from kaiba.casting._cast_to_decimal import cast_to_decimal
+from kaiba.casting._cast_to_integer import cast_to_integer
+from kaiba.models.casting import CastToOptions
+
+
+@safe
+def get_casting_function(cast_to: CastToOptions) -> Callable:
+    """Return casting function depending on name."""
+    if cast_to == CastToOptions.INTEGER:
+        return cast_to_integer
+
+    elif cast_to == CastToOptions.DECIMAL:
+        return cast_to_decimal
+
+    return cast_to_date