macro-polo 0.3.0

Installation

pip install macro-polo

Usage

macro-polo is modular, and can be extended at multiple levels. See the API Reference for more details.

The simplest way to use it is to add a coding: macro-polo comment to the top of your source file (in one of the first two lines). You can then declare and invoke macros using the macro_rules! syntax.

Example (examples/macro_rules/bijection.py):

# coding: macro-polo
"""A basic demonstration of `macro_rules!`."""


macro_rules! bijection:
    [$($key:tt: $val:tt),* $(,)?]:
        (
            {$($key: $val),*},
            {$($val: $key),*}
        )


macro_rules! debug_print:
    [$($expr:tt)*]:
        print(
            stringify!($($expr)*), '=>', repr($($expr)*),
            file=__import__('sys').stderr,
        )


names_to_colors, colors_to_names = bijection! {
    'red': (1, 0, 0),
    'green': (0, 1, 0),
    'blue': (0, 0, 1),
}


debug_print!(names_to_colors)
debug_print!(colors_to_names)

debug_print!(names_to_colors['green'])
debug_print!(colors_to_names[(0, 0, 1)])

$ python3 examples/bijection.py
names_to_colors  => {'red': (1, 0, 0), 'green': (0, 1, 0), 'blue': (0, 0, 1)}
colors_to_names  => {(1, 0, 0): 'red', (0, 1, 0): 'green', (0, 0, 1): 'blue'}
names_to_colors ['green'] => (0, 1, 0)
colors_to_names [(0 ,0 ,1 )] => 'blue'

Viewing the generated code:

$ python3 -m macro_polo examples/bijection.py | ruff format -

names_to_colors, colors_to_names = (
    {'red': (1, 0, 0), 'green': (0, 1, 0), 'blue': (0, 0, 1)},
    {(1, 0, 0): 'red', (0, 1, 0): 'green', (0, 0, 1): 'blue'},
)
print(
    'names_to_colors',
    '=>',
    repr(names_to_colors),
    file=__import__('sys').stderr,
)
print(
    'colors_to_names',
    '=>',
    repr(colors_to_names),
    file=__import__('sys').stderr,
)
print(
    "names_to_colors ['green']",
    '=>',
    repr(names_to_colors['green']),
    file=__import__('sys').stderr,
)
print(
    'colors_to_names [(0 ,0 ,1 )]',
    '=>',
    repr(colors_to_names[(0, 0, 1)]),
    file=__import__('sys').stderr,
)

Interested?

Check out the full documentation and tutorial.