Declarative CLIs with argparse and dataclasses.
Features marked with a ✓ are currently implemented; features marked with a ⊘ are not yet implemented.
- [✓] Positional arguments
- [✓] Boolean flags
- [✓] Integer, string, float, and other simple types as arguments
- [✓] Default values
- [✓] Arguments with a finite set of choices
- [⊘] Subcommands
- [⊘] Mutually exclusive groups
Using dataclass decorator
>>> from argparse_dataclass import dataclass
>>> @dataclass
... class Options:
... x: int = 42
... y: bool = False
...
>>> print(Options.parse_args(['--y']))
Options(x=42, y=True)A simple parser with flags:
>>> from dataclasses import dataclass
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... verbose: bool
... other_flag: bool
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args([]))
Options(verbose=False, other_flag=False)
>>> print(parser.parse_args(["--verbose", "--other-flag"]))
Options(verbose=True, other_flag=True)Using defaults:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... x: int = 1
... y: int = field(default=2)
... z: float = field(default_factory=lambda: 3.14)
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args([]))
Options(x=1, y=2, z=3.14)Enabling choices for an option:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> from typing import Literal
>>> @dataclass
... class Options:
... small_integer: Literal[1, 2, 3]
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args(["--small-integer", "3"]))
Options(small_integer=3)Using different flag names and positional arguments:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... x: int = field(metadata=dict(args=["-x", "--long-name"]))
... positional: str = field(metadata=dict(args=["positional"]))
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args(["-x", "0", "positional"]))
Options(x=0, positional='positional')
>>> print(parser.parse_args(["--long-name", 0, "positional"]))
Options(x=0, positional='positional')Using a custom type converter:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... name: str = field(metadata=dict(type=str.title))
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args(["--name", "john doe"]))
Options(name='John Doe')Configuring a flag to have a default value of True:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... verbose: bool = True
... logging: bool = field(default=True, metadata=dict(args=["--logging-off"]))
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args([]))
Options(verbose=True, logging=True)
>>> print(parser.parse_args(["--no-verbose", "--logging-off"]))
Options(verbose=False, logging=False)Configuring a flag so it is required to set:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... logging: bool = field(metadata=dict(required=True))
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args(["--logging"]))
Options(logging=True)
>>> print(parser.parse_args(["--no-logging"]))
Options(logging=False)Parsing only the known arguments:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... name: str
... logging: bool = False
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_known_args(["--name", "John", "--other-arg", "foo"]))
(Options(name='John', logging=False), ['--other-arg', 'foo'])Configuring a field with the Optional generic type:
>>> from dataclasses import dataclass, field
>>> from typing import Optional
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... name: str
... id: Optional[int] = None
...
>>> parser = ArgumentParser(Options)
>>> print(parser.parse_args(["--name", "John"]))
Options(name='John', id=None)
>>> print(parser.parse_args(["--name", "John", "--id", "1234"]))
Options(name='John', id=1234)Creating argument groups by group title:
>>> from dataclasses import dataclass, field
>>> from argparse_dataclass import ArgumentParser
>>> @dataclass
... class Options:
... foo: str = field(metadata=dict(group="string group"))
... bar: str = field(metadata=dict(group=dict(title="dict group", description="using a dict")))
... baz: str = field(metadata=dict(group=("sequence group", "using a sequence")))
...
>>> parser = ArgumentParser(Options)
>>> parser.print_help()
usage: [-h] --foo FOO --bar BAR --baz BAZ
options:
-h, --help show this help message and exit
string group:
--foo FOO
dict group:
using a dict
--bar BAR
sequence group:
using a sequence
--baz BAZ- @adsharma
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