bagof-magic

Magic is a dataclass-like base built on hint-based magic: field behaviour is driven by type hints and resolved through the sibling bagof-validators and bagof-converters packages.

Unlike a dataclass, options are given as class keyword arguments and are inherited (though an equivalent @magic decorator is also provided):

from bagof.magic import Magic

class Point(Magic, frozen=True):
    x: float
    y: float

# --- or ---

from bagof.magic import magic

@magic(frozen=True)
class Point:
    x: float
    y: float

Per-field behaviour is expressed through annotations rather than a field() function -- including automatic conversion and validation:

from bagof.magic import Magic, ConvertTo, Validate

class Config(Magic):
    port: ConvertTo[int]     # "8080" -> 8080, via bagof-converters
    name: Validate[str]      # rejected unless already a str, via bagof-validators

Most dataclass options are supported (init, repr, eq, order, frozen, slots, kw_only, match_args, ...), plus convert, validate and factory.