Step 6: Final calculator script
Contents
Step 6: Final calculator script¶
In this step, we add a function that returns a legacy argparse.ArgumentParser.
We put the script under a if __name__ == "__main__": guard.
We also had to move the
sphinx-autodoc
style parameter documentation strings to the help keyword argument to avoid problems with the
Sphinx import style (which happens when using the :filename: directive). In standard projects,
where the scripts are part of a Python package imported with the :module: directive, this
problem should not happen.
We now demonstrate the argparse Sphinx extension.
The directive is instantiated like this:
.. argparse::
:module: configpile.calculator
:func: argument_parser
and gives the result below.
Documentation in Sphinx¶
Command-line tool that sums an arbitrary number of floating point values
usage: calculator6.py [--config CONFIG] [--operation {+,*}] [--digits DIGITS]
values
Named Arguments¶
- --config
INI configuration files to parse
- values
Values to sum
- --operation
Possible choices: +, *
Operation to perform, either addition “+” or multiplication “*”
- --digits
Number of digits to display
This number of digits can also be set with the environment variable
DIGITS
Code¶
"""
Calculator tutorial, step 6 (final)
"""
import argparse
from dataclasses import dataclass
from math import prod
from pathlib import Path
from typing import Sequence
from typing_extensions import Annotated
from configpile import Config, Param, Positional, parsers
@dataclass(frozen=True)
class Calc(Config):
"""
Command-line tool that sums an arbitrary number of floating point values
"""
config: Annotated[Sequence[Path], Param.config(help="INI configuration files to parse")]
values: Annotated[
Sequence[float],
Param.append1(
parsers.float_parser,
positional=Positional.ZERO_OR_MORE,
short_flag_name=None,
long_flag_name=None,
help="Values to sum",
),
]
operation: Annotated[
str,
Param.store(
parsers.Parser.from_choices(["+", "*"]),
default_value="+",
help='Operation to perform, either addition "+" or multiplication "*"',
),
]
digits: Annotated[
int,
Param.store(
parsers.int_parser.validated(lambda i: i > 0, "Must be a positive integer"),
default_value="3",
env_var_name="DIGITS",
help="""
Number of digits to display
This number of digits can also be set with the environment variable
``DIGITS``
""",
),
]
def argument_parser() -> argparse.ArgumentParser:
"""
Returns a parser for use for sphinx-argparse
"""
return Calc.get_argument_parser_()
if __name__ == "__main__":
c = Calc.from_command_line_()
fmt_string = f"%.{c.digits}f"
if c.operation == "+":
print(fmt_string % sum(c.values))
elif c.operation == "*":
print(fmt_string % prod(c.values))