Initial commit

.gitignore

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+.pyc
+__pycache__

parsearger/__init__.py

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+import argparse
+from typing import TypeVar, Generic, cast
+
+Value = TypeVar("Value")
+
+
+class Arg(Generic[Value]):
+    value: Value
+
+    def __init__(self, *args, **kwargs):
+        self.args = args
+        self.kwargs = kwargs
+
+    def __set_name__(self, owner, name):
+        owner.arguments.append(name)
+
+    def __get__(self, instance, owner) -> Value:
+        return self.value
+
+
+class TypedNamespace(argparse.Namespace):
+    arguments = []
+    @property
+    def descriptors(self):
+        return [(arg, self.__class__.__dict__[arg]) for arg in self.arguments]
+
+
+Namespace = TypeVar("Namespace", bound=argparse.Namespace)
+
+
+class ParseArger(argparse.ArgumentParser, Generic[Namespace]):
+    def __init__(self, *args, namespace: Namespace, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.namespace = namespace
+        if namespace is not None:
+            for name, descriptor in namespace.descriptors:
+                self.add_argument(f"--{name.replace('_', '-')}", *descriptor.args, **descriptor.kwargs)
+
+    def parse_args(self, args=None) -> Namespace:
+        return cast(Namespace, super().parse_args(args=args, namespace=self.namespace))

parsearger/test.py

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+from parsearger import ParseArger, Arg, TypedNamespace
+
+class CliArgs(TypedNamespace):
+    num_things = Arg[int](help="Some help message", type=int)
+    name_thing = Arg[str](help="Name of some thing")
+
+namespace = CliArgs()
+parser = ParseArger(namespace=namespace)
+args = parser.parse_args()
+args.num_things
+args.name_thing

parsearger/test1.py

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+from collections import namedtuple
+import argparse
+parser = argparse.ArgumentParser()
+parser.add_argument("--num-things", help="Number of things", type=int)
+args.num_things
+
+parser = argparse.ArgumentParser()
+parser.add_argument('--some-arg')
+parser.add_argument('--another-arg')
+MagicNamespace = namedtuple('MagicNamespace', [act.dest for act in parser._actions])
+mn = MagicNamespace()
+mn.some_arg
+mn.foo
+parsed = parser.parse_args(['--some-arg', 'val1', '--another-arg', 'val2'], namespace=mn)
+parsed.some_arg
+parsed.foo