tyro

  

tyro.cli() is a tool for generating CLI interfaces from type-annotated Python.

We can define configurable scripts using functions:

script.py

# Write standard Python
from typing import Literal

def main(
    name: str,
    greet: Literal["Hello", "Hi"] = "Hi",
) -> None:
    """Print a greeting."""
    print(f"{greet}, {name}!")

# Call tyro.cli()
if __name__ == "__main__":
    import tyro
    tyro.cli(main)

→

Terminal

# tyro CLI
$ python script.py --help
usage: script.py [-h] [OPTIONS]

Print a greeting.

╭─ options ──────────────────────────────╮
│ -h, --help         show help message   │
│ --name STR         (required)          │
│ --greet {Hello,Hi} (default: Hi)       │
╰────────────────────────────────────────╯

$ python script.py --name World
Hi, World!

Or using structures like dataclasses:

script.py

# Write standard Python
from dataclasses import dataclass
from typing import Literal

@dataclass
class Args:
    """Configure a greeting."""
    name: str
    greet: Literal["Hello", "Hi"] = "Hi"

# Call tyro.cli()
if __name__ == "__main__":
    import tyro
    args = tyro.cli(Args)
    print(f"{args.greet}, {args.name}!")

→

Terminal

# tyro CLI
$ python script.py --help
usage: script.py [-h] [OPTIONS]

Configure a greeting.

╭─ options ──────────────────────────────╮
│ -h, --help         show help message   │
│ --name STR         (required)          │
│ --greet {Hello,Hi} (default: Hi)       │
╰────────────────────────────────────────╯

$ python script.py --name World
Hi, World!

Other features include helptext generation, nested structures, subcommands, and shell completion.

Why tyro?

1. Define things once. Standard Python type annotations, docstrings, and default values are parsed to automatically generate command-line interfaces with nice helptext.

2. Static types. Unlike tools dependent on dictionaries, YAML, or dynamic namespaces, arguments populated by tyro are better undestood by IDEs and language servers, as well as static checking tools like pyright and mypy.

3. Modularity. tyro supports hierarchical configurations, which make it easy to decentralize definitions, defaults, and documentation.