posmatch 0.3.0

Positional subpattern matching for custom classes.

Positional subpattern matching for custom classes.

Requirements

Python 3.8 or higher.

Note: This package itself does not require Python 3.10, but its usage only makes sense with the new pattern matching feature introduced in Python 3.10.

Installation

pip install posmatch

Usage

Example 1

Using the pos_match decorator.

from posmatch import pos_match

@pos_match
class Color:

    def __init__(self, r, g, b):
        self.r = r
        self.g = g
        self.b = b


color = Color(64, 64, 64)

match color:
    case Color(r, g, b) if r == g == b:
        print('shade of grey')
    case _:
        print('other color')

Result:

shade of grey

Example 2

Using the PosMatchMeta metaclass.

from posmatch import PosMatchMeta


class Color(metaclass=PosMatchMeta):

    def __init__(self, r, g, b):
        self.r = r
        self.g = g
        self.b = b


color = Color(0, 0, 64)

match color:
    case Color(0, 0, b):
        print('shade of blue')
    case _:
        print('other color')

Result:

shade of blue

Example 3

Using the PosMatchMixin mix-in class.

from posmatch import PosMatchMixin


class Color(PosMatchMixin):

    def __init__(self, r, g, b):
        super().__init__()
        self.r = r
        self.g = g
        self.b = b


color = Color(255, 0, 0)

match color:
    case Color(r, 0, 0):
        print('shade of red')
    case _:
        print('other color')

Result:

shade of red