base: Add make_config

Signed-off-by: John Andersen <[email protected]>

Author: pdxjohnny

CHANGELOG.md

@@ -30,6 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `contextlib` exit stacks. Provides temporary file creation.
 - Automatic releases to PyPi via GitHub Actions
 - Automatic documentation deployment to GitHub Pages
+- Function to create a config class dynamically, analogous to `make_dataclass`
 ### Changed
 - CLI tests and integration tests derive from `AsyncExitStackTestCase`
 ### Fixed

dffml/base.py

@@ -216,9 +216,51 @@ def config(cls):
     datacls._replace = lambda self, *args, **kwargs: dataclasses.replace(
         self, *args, **kwargs
     )
+    datacls._asdict = lambda self, *args, **kwargs: dataclasses.asdict(
+        self, *args, **kwargs
+    )
     return datacls
 
 
+def make_config(cls_name: str, fields, *args, namespace=None, **kwargs):
+    """
+    Function to create a dataclass
+    """
+    if namespace is None:
+        namespace = {}
+    namespace.setdefault("_fromdict", classmethod(_fromdict))
+    namespace.setdefault(
+        "_replace",
+        lambda self, *args, **kwargs: dataclasses.replace(
+            self, *args, **kwargs
+        ),
+    )
+    namespace.setdefault(
+        "_asdict",
+        lambda self, *args, **kwargs: dataclasses.asdict(
+            self, *args, **kwargs
+        ),
+    )
+    kwargs["eq"] = True
+    kwargs["init"] = True
+    # Ensure non-default arguments always come before default arguments
+    fields_non_default = []
+    fields_default = []
+    for name, cls, field in fields:
+        if (
+            field.default is not dataclasses.MISSING
+            or field.default_factory is not dataclasses.MISSING
+        ):
+            fields_default.append((name, cls, field))
+        else:
+            fields_non_default.append((name, cls, field))
+    fields = fields_non_default + fields_default
+    # Create dataclass
+    return dataclasses.make_dataclass(
+        cls_name, fields, *args, namespace=namespace, **kwargs
+    )
+
+
 class ConfigurableParsingNamespace(object):
     def __init__(self):
         self.dest = None