Final tweaks for 0.3.0

- Make --field_name and --field-name interchangeable
- Add prefix_names option to extras.subcommand_type_from_defaults()

dcargs/_cli.py

@@ -158,12 +158,26 @@ def cli(
         prefix="",  # Used for recursive calls.
     )
 
+    # Read and fix arguments. If the user passes in --field_name instead of
+    # --field-name, correct for them.
+    args = sys.argv[1:] if args is None else args
+
+    def fix_arg(arg: str) -> str:
+        if not arg.startswith("--"):
+            return arg
+        if "=" in arg:
+            arg, _, val = arg.partition("=")
+            return arg.replace("_", "-") + "=" + val
+        else:
+            return arg.replace("_", "-")
+
+    args = list(map(fix_arg, args))
+
     # If we pass in the --dcargs-print-completion flag: turn termcolor off, and get the
     # shell we want to generate a completion script for (bash/zsh/tcsh).
     #
     # Note that shtab also offers an add_argument_to() functions that fulfills a similar
     # goal, but manual parsing of argv is convenient for turning off colors.
-    args = sys.argv[1:] if args is None else args
     print_completion = len(args) >= 2 and args[0] == "--dcargs-print-completion"
 
     formatting_context = _argparse_formatter.ansi_context()

dcargs/_strings.py

@@ -9,7 +9,7 @@
 
 from . import _resolver
 
-dummy_field_name = "__dcargs_dummy_field_name__"
+dummy_field_name = "__dcargs_dummy_field__"
 
 
 def _strip_dummy_field_names(parts: Iterable[str]) -> Iterable[str]:

dcargs/extras/__init__.py

@@ -1,7 +1,7 @@
 """The :mod:`dcargs.extras` submodule contains helpers that complement :func:`dcargs.cli()`, but
 aren't considered part of the core interface."""
 
-from ._base_configs import subcommand_union_from_mapping
+from ._base_configs import subcommand_type_from_defaults
 from ._serialization import from_yaml, to_yaml
 
-__all__ = ["subcommand_union_from_mapping", "to_yaml", "from_yaml"]
+__all__ = ["subcommand_type_from_defaults", "to_yaml", "from_yaml"]

dcargs/extras/_base_configs.py

@@ -7,12 +7,18 @@
 T = TypeVar("T")
 
 
-def subcommand_union_from_mapping(
-    default_from_name: Mapping[str, T], descriptions: Mapping[str, str] = {}
+def subcommand_type_from_defaults(
+    defaults: Mapping[str, T],
+    descriptions: Mapping[str, str] = {},
+    *,
+    prefix_names: bool = True,
 ) -> Type[T]:
-    """Returns a Union type for defining subcommands that choose between nested types.
+    """Construct a Union type for defining subcommands that choose between defaults.
 
-    For example, when `default` is set to:
+    This can most commonly be used to create a "base configuration" pattern:
+        https://brentyi.github.io/dcargs/examples/10_base_configs/
+
+    For example, when `defaults` is set to:
 
     ```python
     {
@@ -36,7 +42,7 @@ def subcommand_union_from_mapping(
     ]
     ```
 
-    This can be used directly in dcargs.cli:
+    The resulting type can be used directly in dcargs.cli:
 
     ```python
     config = dcargs.cli(subcommand_union_from_mapping(default_from_name))
@@ -70,8 +76,16 @@ def train(
     return Union.__getitem__(  # type: ignore
         tuple(
             Annotated.__class_getitem__(  # type: ignore
-                (type(v), subcommand(k, default=v, description=descriptions.get(k)))
+                (
+                    type(v),
+                    subcommand(
+                        k,
+                        default=v,
+                        description=descriptions.get(k),
+                        prefix_name=prefix_names,
+                    ),
+                )
             )
-            for k, v in default_from_name.items()
+            for k, v in defaults.items()
         )
     )

examples/05_hierarchical_configs.py

@@ -34,7 +34,7 @@ class OptimizerConfig:
 @dataclasses.dataclass
 class ExperimentConfig:
     # Various configurable options for our optimizer.
-    optimizer: OptimizerConfig
+    optimizer_config: OptimizerConfig
 
     # Batch size.
     batch_size: int = 32

examples/10_base_configs.py

@@ -97,9 +97,9 @@ class ExperimentConfig:
 
 if __name__ == "__main__":
     config = dcargs.cli(
-        dcargs.extras.subcommand_union_from_mapping(base_configs, descriptions),
+        dcargs.extras.subcommand_type_from_defaults(base_configs, descriptions),
     )
-    # Note that this is equivalent to:
+    # ^Note that this is equivalent to:
     #
     # config = dcargs.cli(
     #     Union[

tests/test_nested.py

@@ -38,6 +38,31 @@ class Nested:
         dcargs.cli(Nested, args=["--x", "1"])
 
 
+def test_nested_accidental_underscores():
+    @dataclasses.dataclass
+    class B:
+        arg_name: str
+
+    @dataclasses.dataclass
+    class Nested:
+        x: int
+        child_struct: B
+
+    assert (
+        dcargs.cli(Nested, args=["--x", "1", "--child-struct.arg-name", "three_five"])
+        == dcargs.cli(
+            Nested, args=["--x", "1", "--child_struct.arg_name", "three_five"]
+        )
+        == dcargs.cli(
+            Nested, args=["--x", "1", "--child_struct.arg-name", "three_five"]
+        )
+        == dcargs.cli(Nested, args=["--x", "1", "--child_struct.arg_name=three_five"])
+        == Nested(x=1, child_struct=B(arg_name="three_five"))
+    )
+    with pytest.raises(SystemExit):
+        dcargs.cli(Nested, args=["--x", "1"])
+
+
 def test_nested_default():
     @dataclasses.dataclass
     class B:

tests/test_union_from_mapping.py

@@ -15,7 +15,7 @@ def test_union_from_mapping():
         "two": A(2),
         "three": A(3),
     }
-    ConfigUnion = dcargs.extras.subcommand_union_from_mapping(base_configs)
+    ConfigUnion = dcargs.extras.subcommand_type_from_defaults(base_configs)
 
     assert dcargs.cli(ConfigUnion, args="one".split(" ")) == A(1)
     assert dcargs.cli(ConfigUnion, args="two".split(" ")) == A(2)
@@ -32,7 +32,7 @@ def test_union_from_mapping_in_function():
 
     # Hack for mypy. Not needed for pyright.
     ConfigUnion = A
-    ConfigUnion = dcargs.extras.subcommand_union_from_mapping(base_configs)  # type: ignore
+    ConfigUnion = dcargs.extras.subcommand_type_from_defaults(base_configs)  # type: ignore
 
     def main(config: ConfigUnion, flag: bool = False) -> Optional[A]:
         if flag: