feature: Support Pydantic V2 (#35)

.editorconfig

@@ -9,6 +9,7 @@ trim_trailing_whitespace = True
 
 [*.py]
 charset = utf-8
+max_line_length = 88
 
 [*.{yml,yaml,md,toml}]
 indent_size = 2

.github/workflows/ci.yaml

@@ -39,7 +39,7 @@ jobs:
           cache: pip
           cache-dependency-path: setup.cfg
           check-latest: true
-      - run: pip install -e '.[test]'
+      - run: pip install -e '.[test,pydantic]'
       - run: coverage run -m pytest
       - run: |
           coverage report

.pre-commit-config.yaml

@@ -66,9 +66,10 @@ repos:
           - types-setuptools==65.3.0
           - phantom-types==0.17.1
           - abcattrs==0.3.2
-          - typing-extensions==4.3.0
+          - typing-extensions==4.6.3
           - hypothesis==6.54.4
           - immutables==0.19.0
+          - pydantic==2.0b3
   - repo: https://github.com/pre-commit/mirrors-prettier
     rev: "v2.7.1"
     hooks:

README.md

@@ -8,6 +8,12 @@
     <a href=https://pypi.org/project/immoney/><img src=https://img.shields.io/pypi/pyversions/immoney.svg?color=informational&label=Python alt="Python versions"></a>
 </p>
 
+### Installation
+
+```shell
+$ pip install --require-venv immoney
+```
+
 ### Design goals
 
 There are a few core design aspects of this library that each eliminate entire classes
@@ -135,5 +141,73 @@ Traceback (most recent call last):
 KeyError: 'foo'
 ```
 
-For custom currency implementations, `immoney.registry.CurrencyCollector` can be used to
-construct a custom registry.
+#### Custom currency registries
+
+The library ships with a sensible set of default currencies, however, you might want to
+use a custom registry for two reasons:
+
+- You want to use non-default currencies.
+- You only want to allow a subset of the default currencies.
+
+To achieve this, you can construct a custom set of types. It's recommended to use a
+custom abstract base class for this, this way things will also play nice with the
+Pydantic integration.
+
+```python
+import abc
+from typing import Final
+from immoney.registry import CurrencyCollector
+from immoney.currencies import Currency
+
+__currencies = CurrencyCollector()
+
+
+class SpaceCurrency(Currency, abc.ABC):
+    ...
+
+
+class MoonCoinType(SpaceCurrency):
+    subunit = 100_000
+    code = "MCN"
+
+
+MCN: Final = MoonCoinType()
+__currencies.add(MCN)
+
+
+class JupiterDollarType(SpaceCurrency):
+    subunit = 100
+    code = "JCN"
+
+
+JCN: Final = JupiterDollarType()
+__currencies.add(JCN)
+
+custom_registry: Final = __currencies.finalize()
+```
+
+#### Pydantic V2 support
+
+Install a compatible Pydantic version by supplying the `[pydantic]` extra.
+
+```shell
+$ pip install --require-venv immoney[pydantic]
+```
+
+The `Currency`, `Money`, `SubunitFraction` and `Overdraft` entities can all be used as
+Pydantic model fields.
+
+```pycon
+>>> from pydantic import BaseModel
+>>> from immoney import Money
+>>> from immoney.currencies import USD
+>>> class Model(BaseModel, frozen=True):
+...     money: Money
+>>> print(instance.model_dump_json(indent=2))
+{
+  "money": {
+    "subunits": 25000,
+    "currency": "USD"
+  }
+}
+```

setup.cfg

@@ -27,8 +27,8 @@ package_dir =
 packages = find:
 python_requires = >=3.10
 install_requires =
-    phantom-types>=0.16.0
-    typing-extensions>=4.2.0
+    phantom-types>=2.1.0
+    typing-extensions>=4.6.3
     abcattrs>=0.3.2
     immutables>=0.19.0
 
@@ -39,6 +39,9 @@ where = src
 immoney = py.typed
 
 [options.extras_require]
+pydantic =
+    pydantic>=2.0b3
+
 test =
     pytest
     coverage
@@ -101,3 +104,4 @@ exclude_lines =
     pragma: no cover
     # ignore non-implementations
     ^\s*\.\.\.
+    ^\s*if TYPE_CHECKING:$