Step 4: Many positional arguments
Contents
Step 4: Many positional arguments¶
Some scripts may get a variable number of values. Here we update our calculator so that it takes an arbitrary number of positional values.
Note that the field type has changed: instead of float, it is now a Sequence[float].
The parameter declaration changed as well: we now use the append1()
static method of Param, which works by taking a parser of a given type,
here float, to collect the values of a parameter of type Sequence[float].
Code¶
"""
Calculator tutorial, step 4
"""
from dataclasses import dataclass
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
"""
#: Values to sum
values: Annotated[
Sequence[float],
Param.append1(
parsers.float_parser,
positional=Positional.ZERO_OR_MORE,
short_flag_name=None,
long_flag_name=None,
),
]
c = Calc.from_command_line_()
print(sum(c.values))
Executions¶
$ python ../../examples/calculator4.py --help
usage: ../../examples/calculator4.py values
Command-line tool that sums an arbitrary number of floating point values
optional arguments:
values Values to sum
$ python ../../examples/calculator4.py 1 2 3 4
10.0